The Gravel Pit

Proper Casting Sand At Last

2007-06-16T01:04:00.000+12:00

Finally started getting better results with the gecko project. We got some commercial greensand at school. I spent the better part of a day figuring out how to temper it up with water. I purchased a water sprayer, some large plastic buckets and some sieve gauze. It was really a matter of trial and error starting with a couple of handlfuls of sand and slowly adding water with the sprayer until I got the texture I wanted. The commercial stuff definitely bonds better than the ground up cat litter version I make at home and the sand is unbelievably fine.
Cellphone camera isn't the best tool for documenting the process but here's the obligatory post pour photo and a shot of the new mini furnace which fits the small crucible.I'm using it here on my first cast for parts for my gingery style lathe.

Shooting Eggs

2007-06-10T21:04:00.001+12:00

What The Eye Didnt See - For more funny movies, click here

The quickest way to melt Aluminium

2007-06-10T20:43:00.000+12:00

How To MAKE THERMITE ! - video powered by Metacafe

My inalienable right to bear arms

2007-06-05T19:59:00.000+12:00

Found this cat up a tree after some gun wielding nut shot his Mom. Has turned out to be a damned fine cat so far (If a little small)I have named him "Chicken Giblets" because all the good names were taken. (Chicken Giblets are those gross looking things you find in a small plastic bag stuffed up the ass of a frozen chicken. Notice how skillfully he lifts his leg to scratch one of the 200 or so fleas he has.

New Mini Furnace Setup

2007-06-05T19:40:00.000+12:00

A new crucible turned up at school today so this demanded a new set up to use it.

First thing to do was make tongs and pouring shank for it out of 1/4 round bar
And look it not only slices and dices but pours molten metal too
The 10 litre furnace. Two five litre drums cut together and lined with kaowool Next mission is to make some moulding flasks. I broke down an took up the offer of commercially made greensand. At least I'll learn what it's supposed to look and feel like. Semester assessments are coming up and I'll still don't have anything solid to show for it all. Plenty of learning, few results.

OK longtime No Post

2007-06-01T04:28:00.000+12:00

It has been way to long since I journaled my progress. I got sidetracked on a whole other blog. It had 4000 view in it's first ten days and I learnt some good stuff about Internet marketing, overstepped the mark countless times, had a whole lot of fun. In the end I shut it down because I just wasn't getting anything done. So anyway I'm back. Till the next time anyway. What have I done in the last 18 days?
Conducted some experiments in investment casting.
I saw on Grantham's.com investments being made inside metal tubes. I should have read Don's instructions better because I had some problems.

In reflection the problems were simply my not paying attention to detail.
The pipe I used was rusty so the oxide scale flaked off and burnt causing a mess in the kiln.
The scale expanded inside the tubes and crushed the investment mix.
I must have taken the kiln too high because the investment had deformed.
When I burnt out the pipes I ramped the temperature to steeply, the steam in the investment built up pressure and blew out like a Christmas cracker.

I think that the first three items here could be resolved simply by exchanging the pipe for stainless steel dairy tube or Sched10 pipe.
The last two are just procedure issues.
Ramp would be better being 25 degrees C per hour. Original ramp was 50 *C
I must remember to use vermiculite on the kiln shelf to catch any cock ups.

Meta Thinking

2007-05-11T23:25:00.000+12:00

I read an interesting and useful post on Entrepreneurs Journey today about the concept of Meta Thinking. It boils down to taking time out to step back and consider what my purpose is in an activity, and what does it mean to me. Just as Meta-Data is global data that describes other data, Meta thinking is thinking that considers how thinking takes place.
I started this blog as a way of documenting my activities in a couple of subjects at the Technical Institute I attend and it seems to have developed in some unexpected ways.
The main subject I am documenting is called "Scales and Multiples" where the object is to take an artwork and explore what happens to it when you play around with the scale, for example a model of a building produced prior to actual construction and the quantity produced. When an item is designed for mass production there is a journey from prototype to the final sold article. There are decisions to be made about the materials used and the way an item is made, who the end user might be, it's expected useful lifetime or obsolescence. These are all factors that influence the final product which may be rather different from the original idea or prototype.
Last year I produced a run garden ornaments which I sold via online auction quite successfully. As a saleable item it was successful as a profitable item it was not. The time involved in making the article meant that it only paid about ten dollars an hour for my time, not even accounting for advertising, distrubution and servicing clients.
I wanted to revisit this item and tackle the issue of profitability as it pertains to the Scales and Multiples brief. I have explored various ways of casting it and found none to be cost effective. I have explored having the item made in bulk through outsourcing and learnt about economies of scale. I have spent so much time in examining process and technique that I find myself in the position now of coming to the end of the semester with little physical work to show for it.
And while all this has been going on a strange thing has been happening in the background, and that has been this blog. I began with the intention of the only readers being myself, my tutors and maybe my family, and on about the third day a random person turned up, and then another.
I started to wonder if I could actually encourage people to come and view it so I did some research and started doing all the things you do to drive traffic to your blog, and it has been growing daily. Yesterday in it's third week I received 220 visitors. I signed on as part of a Webring and became obsessed with the statistics of who was generating the most traffic for the Webring. Yesterday I reached the number two position and my first thought was what do I need to do to reach number one. (Number one would require approximately three times the traffic volume ). I followed a link on a site to Google adsense and tried it out, and became obsessed with trying to monetize my site. I was delirious when I made my first dime, I'm making about enough for a cup of coffee a day so I'm not going to retire just yet.
And yet again, while all this was taking place another strange thing was happening. Precession.
Precession is a theory in which if you have a goal in mind clearly enough and if it is in integrity with your true self then the results you want often come, but at a tangent to the direction you thought you were taking. My experience of precession has been this. While I have been writing this blog and developing a readership, I have started feeling committed to providing new content on an almost daily basis. So much so that I get a lousy night's sleep if something has stopped me from posting that day. ( You might have realised by now that I have a bit of an obsessive personality). In needing to post frequently I have needed to produce new work to post about, which has meant that I have actually been more productive in the last three weeks than I have since I was a teenager. (I may be at school but I'm staring down the barrel of Forty). Somewhere along the way I have managed to learn a great deal and improve my grades at school.
So that was my three hundred words worth of Meta-thinking, and that while I have little physical work to show for it all I have learned some important lessons as a wannabe artist. (If your still awake Lyndsay and Faith take this into account when you mark my work).
OK enough babble.
No pictures today, but I've been working on extending my lost wood casting concept. I'm making a Tea Light candle holder for SheWhoMustBeObeyed and I figured that Lost Wood might be an interesting way of doing it. Turns out that you get in a power of shit with her indoors if you spend three weeks obsessing about a blog. Photos to follow: stay tuned.

Lost Wood Casting

2007-05-09T14:23:00.000+12:00

Following on from the Natural Architecture post earlier this week I poured the magnolia seedpods today. I burnt the wood out of the investment last night and poured them first thing this morning. Out of four investments I got three finished pieces. The fourth I managed to destroy by trying to blow the wood ash out of the investment with a dust gun and compressor. The other three I ignored the ash and just poured them. As it happens the ash had no effect on the finished castings.

From Metal Casting

I made a box out of bricks put put the investments in in and plugged the sprues with clay. I filled around the box with sand, dusted off the tops, removed the clay plugs and poured the hot shiny goodness in.
I pulled out the cast and dropped it in a bucket of water, the investment cracked off and look at the treasure I found inside.Now that I know the process works I'm going to be scrambling around finding other things to cast this way. Leaves..branches..flowers..insects..rodents..cats..dogs..the wife?
It also makes me wonder whether I could build wooden patterns for machine parts and cast them this way.

Metal Casting Monday

2007-05-08T21:14:00.000+12:00

Decided to have a melting session today and cast a few gecko wall hangings.

From Holding Tank

The open mould was leveled in the sand
Then we have a gratuitous 'inside the furnace' picture.SuperNeverHeardOfSafetyMan skims the dross. Dross is a scum which floats on the surface of the molten metal.Pulling the top off the furnace. Hey we got gloves on.Using the crucible tongs to lower the crucible into the pouring shank.Pouring the hot shiny liquid into the open mould.Letting it cool, flat camera batteries, finished product photos in a later edition.

Natural Architecture

2007-05-07T18:37:00.000+12:00

The magnolia cones are falling in New Zealand at the moment. I picked up a few today and thought I'd have a crack at casting some. I'm taking a bit of a punt here by deciding to just invest the cones directly and see if I can't burn them out of the investment in the kiln.

I formed a cone shaped sprue out of clay and planted the stalk of the seedpods in the clay. Then I put a PVC tube flask around the seedpods, paying more attention to sealing the flask this time.

I wasn't entirely sure that when I poured the investment in, the seedpods wouldn't float to the surface so I committed an investment casting no-no and half filled the flasks and let the investment firm up before pouring the second half. I may get away with it, I may not.

I'll fire them up tomorrow with a 50 degree celcius an hour ramp and a peak temperature of 650. I'll give them a three hour soak to see if the seedpods will actually burn out. Here's hoping.
If it works then I have a whole heap of ideas for things I can try around this process.

Gecko Investment Casts

2007-05-05T19:01:00.000+12:00

I spent some time on the gecko project today. I've been making some single sided wall hangings along with the free standing lizards.

From gecko

This is a wax imprint taken from the top half of the two piece mould seen in earlier posts. Its located in a makeshift formwork cut with the foam saw (Had to use it for something) Glue gunned together and dipped in hot wax (around 65 degrees celcius max) and sealed with a fine clay.
The next step is to mix up the plaster investment. Hopefully I will be able to get a couple of aluminium casts out of this mould if I'm careful. The investment mix is 1 part fast setting plaster of Paris, 1 part silica dioxide (Silica flour from pottery suppliers) and 1 part cold water by volume. The water is measured into a bucket, the the silica is poured in gently and finally the plaster.
If you use a bucket you should get a small hill of plaster sitting above the surface of the water.let the bucket sit for 5 minutes until the plaster at the surface looks waterlogged. This stops lumps forming in the plaster.
When you mix it, don't stir, just put your hand in to the bottom of the bucket and squish the mix between your fingers until it's thoroughly mixed. It kinda feels like soft mud while your doing this. Mix in a couple of handfuls of glass fibre chopped into short lengths, this reinforces the mould and stops it flying apart if something goes wrong when you pour metal into it.

From Holding Tank

Then pour the mix into the formwork starting from the lowest point. Keep drizzling the mix in slowly to a single spot. This lets the mould fill evenly and expels air bubbles as it goes. Then give the formwork a couple of sharp taps and walk away. Don't go near for at least 90 minutes. Vibration now while it cures will weaken the mould and may cause failure. After 90 minutes steam out the wax. I've been using a modified wallpaper steamer at school and it does the trick. Then as soon as the wax is steamed out transfer the mould to a kiln and ramp the temperature 50 degrees an hour to 650 degrees celcius, hold an hour and ramp down to 400 before removing and pouring. This ensures all the wax is burnt off and minimises thermal shock when the metal is poured in.
I tend to bury the mould in sand before pouring to stifle any leaks and offer an extra layer of safety in case the mould explodes. I like to plug the sprue of the mould with clay while I bury it and pull the clay plug out just prior to casting. This keeps any shit from falling in the mould. Obviously an open mould like this one can't be plugged but needs to be dusted out prior to casting.

Gecko Casts: alternative Scooby Doo ending.

2007-05-05T18:30:00.000+12:00

I also took a shot at investing one of the freestanding geckos. The Gecko was stuck to the worktable, sprue down, with clay. I took the opportunity to build up the sprue with clay and extend the vent riser.

From gecko

I used a piece of 6" PVC Pipe as a moulding flask. The flask needs to be at least an inch bigger all round that the wax imprint. The PVC is split lengthways to make it possible to get it off the cured mould. The split is sealed with clay from the inside and the flask is reinforced with tape wrapped around the outside.Clay is used to seal the flask to the table. The clay needs to be quite thick and well bedded so that the flask does not come loose when you pour the wet investment in due to hydrostatic pressure.

SEE! I Told You So!OK I'm going home to get changed and I'll carry this thread on tomorrow. F**K IT!.... the things I do for art... I don't know... (walks off mumbling...)

Interesting Moulding Flask

2007-05-04T15:52:00.000+12:00

I came across an interesting moulding flask design today. It appears to be welded out of angle iron. I want to get opinions from the rest of the castinghobby gang and see whether they think it's a workable design to scale up for bigger flasks. Or is this the world's dumbest moulding flask? Don't forget to vote and comment . Apart from the simplicity of construction I actually like the look of it and it gves me a good idea for a sculpture.

From Aluminium Cas...

Furnace Improvements

2007-05-02T17:39:00.000+12:00

In response to a discussion on the CastingHobby newsgroup about the best way of breaking down large scrap aluminium into usable ingot's for casting I decided to modify my furnace.I have a number of engine shortblocks and gear cases to melt down. My idea was to coil a clay base for the furnace with high sides and a funnel outlet which can be plugged and tapped cupola style.

From Metal Casting

Although the picture doesn't show it well, there is an aperture through the wall of the clay at the top of the spill way (protrusion at left hand side) which will be plugged with a clay bod at casting time. I'll make a plinth in the middle for the piece being melted to sit on while melting begins and the aluminium should pool in the bottom until I get a full well which can be tapped off to ingots.The top half of the furnace which is lined with Kaowool should sit on here quite nicely.
I'll give the whole thing a few days to dry before I decide whether o fire the base in a kiln before I use it or just go for it. This is more of a proof of concept version so I'm happy to just keep patching for a while.
I read a post on castinghobby about an idea for a 44 gallon drum tilting reverbatory furnace for breaking down scrap. If this doesn't work I'm going to develop that idea.

Metal Cutting Lathe

2007-05-01T17:28:00.000+12:00

My other spare time project at the moment is a gingery style lathe. Gingery "style" I say because I am making a lot of changes to suit my needs. Dave Gingery's book is an awesome resource but I am sure he wanted people to use it as a starting point and put there own signature on their lathes. Mine concept is for a gear driven lathe with a variable speed drive. I'm thinking I'll only need a top speed of 500 rpm and want to be able to get down to 100rpm, I've even considered using a stepper based gear motor.
I started cutting the patterns for the lathe as described in the book but once I got going I decided that it just didn't spin my tyres aesthetically, so I'm modeling the design I want in Google Sketchup where I can simplify the construction process and test how different pieces will fit together. When I get the 3d model working I'll mock it up in MDF and see how it fits together and where it can be improved in the real world. I want to investment cast the parts so I don't have to compromise the aesthetic, and I'll have the parts that required scraping in the book commercially planed. I'm just too busy and too lazy to spend a week doing something by hand that a machine can do better for a hundred bucks.
I've read these "I'm gonna start a Gingery Lathe" posts on a hundred websites and two years later they still haven't made any progress. I've also seen a few site's where people have made outstanding jobs of them. It's a huge undertaking and since I don't want it to be another project that falls by the wayside I need to make it as simple and achievable as possible.

Finished Foam Saw

2007-05-01T16:56:00.000+12:00

From Foam Saw

The finished foam saw. Well as far as it's come so far. I'm working on the circle cutting accessory at them moment and documenting the process into HTML. Then th e lathe and planer accessory. I need to put a hold on further progress for a week or so while I finish some other schoolwork I have fallen behind on. The foot pedal switch is working out really well. Its momentary action so that when I put my foot on it it heats the wire and when I let go it goes cold. It goes cold almost instantly so I find I am able to stop in the middle of a cut without causing excessive damage to the surrounding foam.
This is the top of the wire which for the moment is providing tension just through the natural springiness of the timber bow arm. I want to replace this with some orm of cam tightening system as I find that the tendency is for the wire to slowly stretch of time so that it needs frequent adjustment.The Bow arm setup. I used cable ties for the moment to secure the wire to the bow arm. It's less tidy than I would like but I want to see how the other accessories are going to work first before I decide on permanent routing of this wire.This is inside the base with the table lifted. The bottom of the cutting wire is secured to the screw in the board across the centre. I still need to secure the wiring loom down. The total projected budget for this project was $2.70 including tax. I had a 100% budget blowout when I bought an extra cup of coffee while I was building it.

Firefox, Google and working smarter not harder.

2007-04-29T01:22:00.000+12:00

I was looking through my site stats today and noticed that 42% of visitors are using Mozilla Firefox. I can understand why. I got it with Google Pack and it Rocks.
I used to use Opera a lot because I liked tabbed browsing and an integrated email client but Opera, which started out at 3mb, lost the plot when it just started getting heavier and slower. They never really sorted out the Java issues either.

The new tabbed browsing IE7 snuck its way into my system, thanks to Bill Gates' insistence that he knows more about how I want my computer to be set up than I do, so I tried it out and found that even though it pretended to be a nice light browser it still was just another clunky MS product that wouldn't handle media well.

So I've become a Firefox convert, it's fast and light and I've yet to find a media system it doesn't work with. I like the endless add ons and widgets that are available. I don't miss having a integrated email client because I use started gmail.
It took me a while to be convinced to use a web based email account for my daily mail again after using Hotmail, and Yahoo, which seemed to filter out all my mail except for the spam.
The whole Google Pack is a pretty cool system. The Picasa Web albums integrate seamlessly with Blogger (Once I realised I need to link my pictures into my posts rather than embed them) and the Picasa image organiser is about the most useful piece of software I have on my computer. It's basic image correction abilities are awesome for tidying up images for the web and it automatically reduces file sizes when I upload to the web.
I like being able to download my camera into albums in Picasa, edit them quickly and then "One Click" them to Picasa Web Albums. From there I only have to generate link codes (which is done for me on my Picasa page) and paste the HTML into my posts. There is an option inside the PC based software to Blog pictures directly to here but having embedded images just eats up too much space.
Google Desktop was in there too which makes searching my computer easier than using the Windows finder.
The other Google thing I use all the time for my school research is Google Notebooks. I frequently research stuff on the net at home, paste it into Notebooks and then when I get to school I can log in and print it out on their machines.
As an adult student, and someone who is hopelessly disorganised, I like not having to carry any books around and nowadays I find I can keep everything on the web and just log in to a handy computer. Even this blog doubles as a workbook for school. My tutors were always on my ass because they never saw my workbooks but they like it because now they can just look here to see what it is that I do all day.
So "SNAPS" to Google all round. I can't wait till they start releasing operating systems, then they'll really own the INTERWEB (If they don't already)

Foam Saw

2007-04-27T18:47:00.000+12:00

Ok. Still no photo's.
Made progress on the foam saw today. Wired it up and added the functionality of putting a foot pedal on/off in the circuit. This will allow me to Use both hands on the polystyrene while I am cutting and not have to scrabble for the switch when things turn to custard or I want to stop in the middle of a cut. I've decided to PDF the entire document as a "How To" e-book type of thing which I will provide a link for. The next step, after I take some photo's of course, (these posts are pretty useless without them)will be to install the lathe section of it.
After posting a question about hooking a dimmer to a transformer on Rec.Crafts.Metalworking and starting a real shit storm I have been researching the power supply issue quite deeply. Over at The CastingHobby forums I have been given a design to make an old AT computer power supply into a variable supply.Although most people scoff the variable supply is important because making top class cuts requires fine temperature control, and the power needed changes with the thickness of foam you are cutting.

I started work today on making patterns for my metalworking lathe. I've only had the book for two years so no hurry. I think the hardest part was actually making the first move. It's such a huge project that committing to start it takes a bit of working up too. I've set myself a finish date of November 22. The day school finishes. Or was that the day JFK got shot? Either way it's not good. Getting shot on the last day of school could spoil your whole summer.
I will have to take the Thomas Edison approach of 'do something on it every day, even if it's just tighten 1 bolt'. That's kind of how this foam saw has been shaping up, I don't like to go to bed at night unless I've done at least something towards finishing it.
Typical of me to take a simple 2 hour project and over complicate the crap out of it.

My Scales and Multiples gecko project is starting to show a definite lack of time input. My next step there is to invest some of the wax forms and actually cast some to see how they turn out. I collected about 100kg of aluminium scrap last weekend so I'm going to spend tomorrow making ingots. It seems like forever since I actually melted some metal, even if it was only last week.

I also want grab the video camera from school and make a Vodcast of a casting session, I would like to integrate this blog onto a real website so that I can store the projects in a more readable manner, and I could see regular Vodcasts being quite a nice feature. Writing the blog has made me a lot more productive as i feel I need to keep doing things so I can keep posting content for my three whole readers (Or is it four now?). Smany ideas, so little motivation. The bloggings great for me in terms of examining what I am doing with my time and what I am learning but trying to follow a project on here from start to finish as a reader is a real pain.

Foam Saw Delays

2007-04-26T00:13:00.000+12:00

Getting assignments finished for school has delayed the continuation of the foam saw for a few days. However I have found an interesting link I thought I'd share. Contour Crafting are working on the ultimate 3D printer. It's a giant scale concrete printer which will print entire homes in the near future.

Have a look at the other foundries in this webring while your here. The links at the bottom of the page.

Foam Saw Update

2007-04-23T21:47:00.000+12:00

Started work on the electrics for the foam saw today. I'll post photos in the morning, but basically it consists of a heavy duty 12V transformer from the lighting in a supermarket chiller, and a domestic light dimmer. The transformer has to be big because the wire is gonna draw several amps of current.
I've read that you should never use a light dimmer to control the output of a transformer but I like to live dangerously. I've never had a problem with the dimmer burning out or anything getting hot (Other than the cutting wire of course ) so I'll keep doing this until either I see some proof or my house burns down.
If anyone knows what the reason is lemme know.
The light dimmer goes on the 220V side of the transformer after the isolating switch. You gotta have an isolating switch and preferably a neon telltale light so that if some idiot (usually me) leaves the cutter on you don't accidentally burn yourself. Gotta say that even though the wire isn't always glowing red it still hurts like ten bastards when you grab the hot wire.
Anyways images coming tomorrow of the power, the table insert and the wire tensioner.
Then we can start on the attachments that will let us use it like a lathe and a planer. For those bits we need to scrounge an old electric screwdriver (although a new Chinese one is about $5), a nylon kitchen cutting board, some 8mm all thread rod, some 8mm nuts and an ac mains voltage gear motor of about 2 rpm. O.K, get scavenging and I'll see you back here tomorrow.

Rapid Prototyping

2007-04-22T15:31:00.000+12:00

A bit off topic but here's a good site to waste an hour at. The RepRap open source project shows you how to build your own rapid prototyping printer for under $400 US. The instructions are clear and simple and while the results aren't yet as good as a $100,000 machine it still about the coolest machine you can make in your own kitchen. It works like a 3 axis CNC router, but extrudes layers of molten plastic in a bead, rather like a hot glue gun.
Although the video shows the machine making a cock up it also demonstrates the kind of work it will do.
Also in the same vein is the David Laser Project which combined with the reprap really gives you the fabled "Santa Claus Machine". The video is tedious but gives you an idea of the concept.

Foam Saw progress

2007-04-20T13:39:00.000+12:00

I've uploaded some images of the foam saw so far.

From Foam Saw

Heres the bones of the unit in timber, actually sawed up school desks. This is the rebate around the base for the sheet of 3mm aluminum plate which forms a dead smooth table. The Base size is 600mm x 600mm I wanted plenty of room to add other features to this like lathe capability and a fence. I opted to go for a vertical wire so that I can use it for freehand cuts. This means my lathe design will have to be vertical, to allow for this I created used a 450mm throat (length of usable hotwire wire)for the saw.This is the retainer for the bow arm to the base. I would still like to cast the bow arm in aluminium as the wooden bow arm has too much flex for my liking. I think this time I will greensand cast itThis is the wire attachment design I have used for the top of the bow arm. If I use guitar string I can place a pin through the loop at the top. I am going to try guitar string this time, previous attempts with nichrome were frustrating as the nichrome becomes brittle after heating and there is a fine line between having the wire hot enough and having it snap.Here is how the table will fit into the base. Ignore the lousy fit as this is actually just a random piece of scrap shoved in for the photo.
More to follow stay tuned.

Strange power of the internet

2007-04-20T10:12:00.000+12:00

I never had any commercial ambitions for this blog but being a starving artist I thought I would try Google Adsense just in case. I've been amazed in two ways. First the tips for getting extra traffic to your blog have given me more traffic here in the first nine hours of today than I've had all month, and second people do actually click the adds and I've made my first dime.
I'm really not interested in putting more commercial content on here as I'm a purist and believe that the internet should be used primarily to share information freely via usergroups, clubs and webrings etc, (and for porn). I do also realise that the commercial aspect has great value too. Frequently I have been able to buy supplies for my various projects from overseas via the net and from the comfort of my own home.
Down here in New Zealand we can be quite limited in what we can just go to a shop and buy, we don't have the economies of scale that the U.S and Europe have so all too often shops with a more eclectic inventory are simply not viable.
It's also interesting to consider what goes into making a site that people want to not only come too but actually return to again and again. Case in point would be Frank Gombiks theworkhop.ca, a site I have been going to for nearly five years and that seems to have become a legend in it's own right.
Any thoughts on this subject would be greatly appreciated. Just click the comments below. If your interested in Adsense I have place a link on the right hand side of the page.

Foam Saw and paper glue.

2007-04-19T21:50:00.000+12:00

Poured the metal for the foam saw arm today, and while the pattern didn't fill completely the surface was pleasing. Although it revealed the wrinkles in the paper in places it didn't have the pitting and characteristically poor surface I normally get using expanded bead type foam. Gluing paper to the outside of the foam before investing it with plaster seems to have been one of my better ideas. I'll get images posted when I find a camera.
For now I have built the saw base and bow arm out of timber. This frees me up to get on with a more important project, building some form of muller/sifter/fluffer thingamabob to give me decent sand to work with. Poor sand quality is the root cause of my last two casting follies.

Order of the day

2007-04-19T04:09:00.000+12:00

Spent the day chopping up sand with a spade. I need to make a motorised sifter and ball mill. The refractory coating on the foam patterns for the foam saw is hard and dry. I was going to cast today but I decided to spend sometime revising the burner for the furnace. I aligned the jet to the center of the blow pipe it's a stop gap measure until I can build a new fan forced burner.

Foam Saw Patterns

2007-04-16T17:31:00.000+12:00

OK, I didn't get as far as pouring the foam saw today, after the ingot fiasco I'd pretty much had my fill for the day. However (This "HOWEVER" was brought to you by Lindsay Marks Graphic Design Tutor)I did glue up the patterns and once I saw their sheer size I lost my bottle and decided to glue on some risers and invest them in a plaster/silica mix. I really don't think they would pour just in dry sand, they are way too long and thin. I can see now I'll have to build custom flasks for them, and have decided I'll give them one shot and if they don't turn out I'll just build them in wood (I know, I know 'what a soft cock' but I really want to get this project out of the way. The casting route is just for bragging rights.) I'll bake them slowly tomorrow at 50 degrees (hoping they don't twist)for a night and pour them on Wednesday. Here's some images of the JOB so far.

The table base pattern Metal Casting

Table Base Close up Metal Casting

Note the paper surface I glued on to smooth out the surface. When I say smooth I use it in the loosest sense of the word. I need to find a glue that doesn't destroy the foam or wrinkle the paper. Worth a try though. Perhaps very thin cardboard would be the way to go.

The bow pattern Metal Casting

Sadly I did not document the bow arm of the saw before I invested it. Though if you use your imagination the flat pieces on the left are where the arm bolts to the base and the right hand end is where the wire goes.

Taking the Good with the BAD!

2007-04-16T16:29:00.000+12:00

Had some success and some failure today. I tried out the eight shot sand ingot mould I talked about in an earlier post here . I used some old ludo mix we had lying around school it had gone rock hard and was full of three years worth of cigarette butts, failed castings and strange fish shaped pieces of pottery that were swimming far from the sea. I guess that's what happens when you put your casting sand in a rubbish bin. I mixed it with water in a wheel barrow and chopped it up fine, I then dumped it out on the concrete to dry up before breaking it up again. The Ludo had a really puggy, spongy feel to it. I suspect it was about 50% old pottery clay people had dumped in there over the years. 'Anyways' I rammed it up into the mould and flipped it out in the sandpit. A sharp sideways rap loosened it up and the mould lifted out beautifully. The ingot moulds were sharp and very firm a bonus I guess of the high clay content. So far so good.
I loaded up the biggest steel pipe crucible I could find with my entire collection of aluminium scrap (Time to go foraging again), set up the furnace and lit her up.
I had the bonus today of working with a pyrometer and I'm a total convert. For the the first time I was able to see what the effect was of different burner settings, and how the size of the exhaust opening affected heating. I was also surprised to find that different areas of the furnace differed in temperature as much as 150 degrees centigrade. I found out that the burner truly is crap and has to go. I hate atmospheric burners with a vengeance, give me a blower driven burner any day. Ii took over an hour and endless tuning to get the melt up to 660 degrees for pouring. When I finally got there I skimmed the dross and tried another first, borax degassing which brought up a whole new kind of scum to the surface. The melt was good hot, clean and shiny. I uncovered the ingot moulds and poured in high expectation of smooth glossy ingots.
DOH! Too much water in the sand at first I couldn't figure out what was going on. I've never been much into greensand casting so it took me by surprise when my beautiful liquid started bubbling and foaming. I persevered and filled the eight moulds as best I could. I then walked off and practiced my four letter vocabulary. Funny how this shit always happens when you have a bit of an audience.

For more disaster close ups view the picasa album Metal Casting

When the mess had cooled a tad I shook it out and started the autopsy
. To be fair I could see that although the ingots were as gassy and ugly as three dollar hooker, the sand moulds had held their shape beautifully. If I had let the moulds dry out overnight things would have gone pretty much as planned. I almost figure with the amount of clay in the sand I could ram up moulds, turn them out on a board and put them away for a week to dry. This way I could produce a whole bunch of ingot moulds in advance for those days when I just wanna melt metal and build up my ingot stock. I'm gonna try it tomorrow. I'll do a full CSI workup on the ingots as well and file a report. Evil Agent Spender Out.

Warmasks

2007-04-15T19:18:00.002+12:00

After seeing some cast aluminium masks on foundry101 I decided I'd like to have a go.

From sculpture

I have these ceramic Warmasks I made last year based on my Visigoth ancestry. They were made on casts taken from my face with dental alginate. I modeled the masks on the plaster casts I took from the alginate in fine white stoneware clay. I have had them stuck to our fence outside but they have been upsetting the dog so "SheWhoMustBeObeyed" made me take them down.

From sculpture

I guess its gonna piss her off even more when I stick the aluminium ones up instead. I'll sandcast them once I make some flasks, once I cut the foam patterns for flasks, once I make a foam saw.... am I seeing a pattern here?

Hot Wire Foam Saw

2007-04-15T18:24:00.000+12:00

I'm finding more and more lately I want to rapid prototype a sculpture or build a tool for a one off job (like the block and tackle). To make this easier I decided today to build a hot wire foam saw. Seems like I'm starting a lot of projects lately without actually pouring any metal into them. Never mind. tomorrow is going to be a melting day so hopefully I can post a bunch of pictures of finished projects. I've taken to the idea of building a foam saw combo like the one shown here at the association of back yard metal casters. I went down to school this afternoon and cut the foam patterns for the saw on the table saw.
Building a foam pattern saw from foam patterns? But don't you need a foam saw to cut the patterns? The more I think about this conundrum the more my head hurts. I waver for a while stuck in inaction but finally the voices in my head tell me it'll all be O.K.
Actually the circular table saw makes a pretty nice job of cutting EPS but the bonus of a hot wire saw is in the way it seals the foam as it cuts for a nice finish. Anyway stay tuned and tomorrow we shall see what we shall see.

Lost Wax Methodology Part 2

2007-04-13T22:47:00.000+12:00

Gecko Update

2007-04-13T00:39:00.000+12:00

Made more wax imprints of the gecko today as well. These are also getting sprued together for investing
I also took a sidestep on this project and created this wax by pouring into only one half of the mould. I'm going to try to cast a few of these as well. I'll cast one in aluminium to use as a pattern for some sand cast reproductions. I think that polishing the lizard form against a sandcast background would look good. I'll also invest one to cast in glass, the varying thicknesses of glass would be interesting.
You may notice that I've changed the wax since my last photo's. The wax I was using was straight paraffin wax and just too brittle to work with. I melted in some yellow microcrystalline I found lying around. It makes it easier to photograph, the candlewax on a plaster background was like photographing a polar bear in a snowstorm.

Lost Wax Methodology Part 1

2007-04-12T23:36:00.000+12:00

Anyone you talk too has a different method of producing investments. Here's my two cents worth.
Take the original item and clay up to a parting line at a point where there are no undercuts that will trap the piece in the mould. You'll need to consider two things when you clay up. One is a method of positive registration of the two halves of the mould when finished and the other is a pouring sprue and shrink reservoir. Positive registration is best achieved with boring a shallow dish into the clay in several spots with cast into the plaster as bumps called "natches" Like "nachos" but better tasting. The image to the right shows the two natches in opposite corners.

Surround the clayed up item in a suitable flask, you need an inch or so of room minimum around the object. Here I've used a piece of PVC pipe split lengthways. The split makes it easier to remove the flask when the plaster sets.

Seal the flask to your working surface and seal the flask split with tape or clay. be fussy here because nothing sucks worse than having wet plaster piss out of your flask and all other the floor. Fine un-grogged pottery clay is probably the second most useful thing in your foundry set up next to a big "Starbucks" coffee mug full of bourbon.
Spray the inside of the the flask and everything inside the inside of the flask with a release agent. I use generic canola oil in an aerosol can, it's cheap, convenient, and nothing sticks to it.
The spray foams up a bit so after spraying the flask I smooth it out and work it in with a soft paint brush.
Next comes plaster. In order to reduce wastage of plaster you can now fill the flask with water to get an idea of how much you'll need. In general it pays to set up and seal your flask on a piece of board so you can move it around easily or in this case tip out the water. Luckily in my case I'm reckless enough to just tip the table up.

Mixing plaster is all science and no art in my book. Stick to the directions on the bag and you'll get repeatable stable results every time. In general 1.4 litres of water to 2kg of plaster makes a pretty pile like this in an ice cream container. Put water in container first and the slide the plaster in on top until you get your own snow volcano. Now don't stir it, walk away and let it sit for 3-5 minutes. This is called slaking, it's letting the plaster soak up water so that when you stir it up you end up with a smooth creamy mix without lumps. Stir it gently with your hand trying not to break the surface of the mix with your fingers, this avoids aerating the mix overly.

When pouring into the flask start pouring into the lowest point in one continuous stream and let the tide slowly rise in the flask. This is the surest way not to end up with air pockets in the final mix. Stop pouring when your an inch over the object give the worktop half a dozen good raps with your fist to knock out any entrapped air in the plaster, and then walk away for at least 90 minutes. The setting nature of plaster means that any vibration in that first hour and a half results in fine cracks in the mould which can induce structural failure later down the track.

After 90 minutes is up you can release the flask, dig out the clay, give the whole thing a gentle wash with a paint brush and running water, and repeat the process above to get the other half of the mould.

The picture above is the first side of the mould showing the clay next to it used to establish a parting line. When you've poured the second both halves of the mould and the required setting time has passed the drop the whole mess in a bucket of water overnight to cure up hard. The water seeps into the joint between the halves and makes separating the two parts easier with less risk of causing damage.

Lost Wax Pulleys

2007-04-12T23:18:00.000+12:00

Wax Imprint of Pulley with attached sprue View Album

Took the wax imprints of the pulleys today. The alignment was excellent but the finish on the wax was a bit naff. I'll drill the locate the center of the pulleys, drill the shaft bore then set them up on the polisher again like I did for the original and tidy them up. I could have made a better job of the split mould, the part line didn't have a positive key to ensure proper location of the two parts and the original needed to be finished smoother prior to moulding. It's always a case of more preparation work up front means an easier job all the way down the line.
Tomorrow I'll sprue the imprints together, invest them in plaster/silica mix and and burn them out in the kiln.

Pulley Block

2007-04-12T07:00:00.000+12:00

I needed a Block&Tackle at home. Being too tight to actually buy one I have decided to build one using a combination of lost wax investment and Lost Foam.
For the body of the pulley block I drew a template in Adobe Illustrator, which is sort of like a handicapped version of CorelDraw, printed it out and glued it to polystyrene sheet. I then cut the parts out on a bandsaw, and glued them together with trusty hot glue. These will now be put into a bucket of dry sand and cast in aluminium.This is a quick and dirty project so I didn't get to fussed with sanding up the foam or coating it to smooth the surface finish.

Templates printed from CorelDraw pulleyblock

Glued together polystyrene parts from pulleyblock

The pulleys need to be a bit more precise so they are being done in a two piece mould

Lost Ice Casting

2007-04-10T23:35:00.000+12:00

I was just playing around with sculpting a piece of ice for an ephemeral piece when I had an idea.

What if I took an ice sculpture or part for something I was building (Ice machines really well with woodworking tools if your really quick or live in Canada) and invested it in a plaster/silica mix?
The ice would start to melt as soon as the plaster started to generate heat on curing but by then the shape would be fixed.
You could even cast the ice in a mould like normal lost wax impression (except that ice expands on freezing). I feel sure that with a little experimentation it could do most things that wax will with the added bonus of water being about a millionth of the price of wax.
A quick search of Google revealed this page: Joseph Harrington's Lost Ice which describes a similar concept in glass casting.

Waxing Lyrical

2007-04-10T16:00:00.000+12:00

A rainy day brought ongoing progress to the gecko project. The top half of the plaster mould was split off with wooden wedges. This was the first time I had opened fresh moulds this way and it produced a controlled separation of the halves with minimal damage to the plaster. Once I had released the metal and clay pattern I made some small adjustments in the places where the pattern had been too tight or undercut in the mould to lift out easily.
I gave the whole thing a good wash out under running water with a soft paint brush, this also makes sure that mould is good and wet. The wax that gets poured in to the mould won't stick to the wet plaster surface. It occurs to me now that in the future I will keep the moulds wrapped in a wet cloth between fills.

Plaster halves clamped and filled with wax

Next I closed the two halves together and secured them together with F-clamps, another first, previously I have used big rubber bands cut from car tyre inner tubes but they really are a pain in the neck. The F-Clamps were quick and rock solid.
The wax was poured in and left for about 15 minutes to cool, I was a little impatient and wanted to see if the pattern had filled or if I would need to revise the gating and riser system. I was surprised to find that the cavity had filled fully and was totally solid. The two halves were once again split with wooden wedges, and the top popped straight off with no problems, it took a few minutes to carefully pry the wax gecko out.

Wax imprint in lower plaster half gecko

The pattern still has some small revisions required. There are parts where there is not enough draft on the pattern to release easily. I'll make these revisions and cast half a dozen waxes in preparation for the next stage.

Picasa Web Album

2007-04-09T22:48:00.000+12:00

Click for full image gallery

All the images from the gecko project are available on my Picasa site by clicking the above image.

Random Nut Of The Month Awards

2007-04-08T22:01:00.000+12:00

In which Pooh and Christopher Robin discuss who is the most interesting fucker in the Hundred Acre Wood.

Found myheap.com today.
It's well worth a visit. Written by a high school arts tutor it gives excellent primers in all manner of mold making and casting.
It also diaries the making of various pieces of machinery and equipment useful when committing Felony Art Crimes.

Also on my list of faves, is Frank Gombiks theworkshop.ca
A diary of a reformed hell raiser who is doing interesting work in the fields of lost foam metal casting, and maple syrup making.

The Gizmologist's Lair takes my award for random nut of the month.
Anyone who builds his son a 1/5 scale model Sherman tank you can hop in and drive complete with compressed air cannon is tops in my book. He has extensive notes on all sorts of useful subjects connected to the home foundry/hobby engineering game.

Gecko Part Quattro (and a half)

2007-04-08T21:51:00.000+12:00

And finally the lino box is supported with bricks and filled with plaster. The plaster mix is 1.4 litres of water to 2kg of dry plaster. The consistency is that of fresh cream. I'll give this two or three days to really cure up before opening as there is quite a lot of detail that could break off when I separate the two halves.

Gecko Part Quattro

2007-04-08T21:48:00.000+12:00

Just another view of the built up piece

Gecko Part Three

2007-04-08T21:34:00.000+12:00

Digging the clay out reveals one half of the gecko buried up to its little gecko ass in plaster. I want to make the lizard more three dimensional so instead of casting the other side straight away I want to build up some relief in clay and add a sprue and risers. The pattern is quite complex and has a lot of air traps in it around the toes come casting time. As you can see the lino wall is built up again and sealed with soft clay. On the left hand side I have scribed text to see if it will come out raised on the top half. Of course it has to be scribed in reverse so it will be correct on the other side.

Gecko Two

2007-04-08T21:17:00.000+12:00

First stage in the process is to establish a parting line for the two piece plaster mould that will be made. The gecko is built up with clay to a midpoint and smoothed back so there are no undercuts.
Then a dam is built around the piece. I built the clay piece on a square of timber and then stapled linoleum to the sides, taped the joins, and sealed the joints with clay.

I skipped a picture but this is after plaster has been poured into the lino box, hardened and pulled apart.

The Gecko Returns

2007-04-05T00:36:00.000+12:00

Yesterday I started work on the gecko casting. First job was to
model the gecko in 3mm aluminium plate.
I drew the lizard in CorelDraw X3, printed it out and glued it to the plate. I used spray photo mount adhesive which was not repositionable. DOH!. Stayed in place great but was a major undertaking to remove when I'd finished. Nevermind...
Once I had the outline glued to the ali plate I proceeded to cut out the gecko on a bandsaw. The inner squiggle I did with a scroll saw. It was the first time I'd used one and I'm a total convert now. The scroll saw blade can turn in its own length and is much easier to control on tight bends.
Having cut out the gecko I tidied up and refined the shape with a range of jewelers files. After about six hours of filing I declared the job finished and started to hammer some shape into the gecko only to break off the left rear leg. A beginners mistake that I saw coming but still made. Aluminum doesn't like to you to change your mind and bend it twice in the same spot.
Rather than start from scratch I have decided to bullshit my way out of my predicament and fix the leg in the next stage.
The next step is to make a two piece plaster mould that I can take wax impressions from. With this in mind I have established a parting line by building up around the lizard with sculptural clay. The clay I used was a grogged sculptural which was hard to work with because of the grit mixed into the body of the clay. Next time I'll either use very fine clay or plasticine. If you click on the second image (The close up of the broken leg) you can see where I sand blasted the gecko to take the tooling marks from the filing out of the surface of the piece. One thing about taking plaster moulds and wax impressions is every flaw is transferred from copy to copy

Tomorrow's first task is build a wall around the model and fill with plaster to end up with one half of the two piece mould.

Casting Sandpit

2007-04-03T22:24:00.000+12:00

Just stepping back a bit to Sunday a fortnight ago. After my first cast with the new furnace at school I realised that I needed to organise somewhere safe and tidy to cast in future. The image on the right is the weed patch that I used. Basically a pile of sand retained by some bricks. It was OK but a bit limiting and altogether too low to the ground to be able to work at safely.

After some scavenging I managed to knock up a new sandpit that gives me extra depth of sand for burying investments into and a clear path for walking with a crucible of hot metal.

Scales and Multiples

2007-04-03T21:14:00.000+12:00

After a slow start I have begun to get into my "Scales and Multiples" assignment. I'm reworking the 'gecko on a koru' idea I had last year. I was bandsaw cutting a 400mm high koru shape from 3mm aluminium sheet, spending 30 minutes cleaning it up and and copper riveting a gecko to it that had been plasma cut using a MDF template from copper sheet.
Sadly I no longer have a photo of one. I sold quite a few on TradeMe as a garden ornament. The item sold well but was a real pain to make and only barely profitable.

My concept is to investment or rammed sand cast the same item.

The benefits are many.

Although there is more raw material used there is less wastage as any scrap can be used regardless of the shape. This means I can buy metal to cast at scrap rates rather than new sheet and plate rates. Copper is currently $8 a kilo to buy as scrap and aluminium is around $2.50 a kilo.
If I am making only one master pattern I can invest the time in making it perfect. Cutting each one individually usually meant that near enough was good enough.
Once I have a master pattern I can cast sub masters, sprue them together and cast multiple numbers of the finished product at once.
I think that the perceived value of a cast product would be higher than that of one cut from sheetmetal. I would have to test that theory though because casting does smack of mass production. I would have to personalise each piece perhaps or produce them in a limited series.

A limited series could be made less limited by taking a modular attitude towards the work. For example I can change the metal they are produced in or change one part of the work eg: gecko on a rock, weta on a koru. You get the picture.

At first I looked at translating the piece into a completely 3 dimensional form but this is more complex than it seems, so for the moment I have gone with changing just the way it is produced. Gotta walk afore I run!

The image attached is of a gecko cut from 3mm aluminium, I'll dress it up and hammer some shape and detail into it and then figure out how I move from this basic pattern to an initial cast master.

Right off the top of my head I am predicting that I will need to make a two piece plaster mould and produce wax imprints .

Methods of casting Pro's and Con's

Lost wax investment route

I will need to be making many items at a go because of the cost of burning out the investment.
Lost wax will give a more faithful reproduction of the master pattern which means I can add finer detail to the piece.
Multiple waxes can be sprued and poured together. This is a more efficient use of the furnace time.
If a pour goes bad I have got more time and money invested and subsequently lost in a multi sprued wax casting. Multi sprue designs are notoriously tricky and can take several attempts to get right.

Rammed greensand route

I will have to make a large number of cope and drag boxes so that I can pour multiple items each time I heat the furnace.
The reproduction of the master is less faithful, but it does have it's own charms.
If one pour goes bad I only lose one piece and less time.
Individual time per piece is probably slightly higher.

Anyhooo enough blabage time for some making

Photography

2007-04-02T22:08:00.000+12:00

With photography being joined to graphic design this year I have taken the opportunity to borrow the cameras and get some practice.Last Friday I went to a friends wedding and shadowed the official photographer. out of the 300+ images I shot I ended up with 70 that I thought were OK, of that about 5 were what I would consider good.
I've uploaded the 70 to my picassa web album. Spent most of the time exploring different exposures, the effect of the flash, and different focal lengths.
Made the mistake of taking only one lens for the Canon 300D (the 18-55mm) great for macro and up close but hopeless for getting decent shots at the actual ceremony. Still, live and learn

Honeycomb Sculpture

2007-04-02T22:02:00.000+12:00

The cast of the honeycomb. It's currently down in Auckland getting a satin chrome electroplate finish. Next on the list will be to make a flexible silicon mould of this so I can makes some wax duplications to be casted in different materials.

Ingot moulds

2007-04-02T21:49:00.000+12:00

Also found sometime to knock together Version 2.0 of the ingot moulds. This is will make eight moulds at a time. I have yet to test it to see if I can actually ram it up and release the sand but I don't expect any problems. I have used a draft angle on the moulds of 5 degrees, rather than the minimum 1 degree, so they should slip straight out.
Would quite like to get fancy and carve a logo into the moulds so I get branded ingots. God is in the details.
I'm pretty pleased with the progress I'm making on this project so far, it's not my usual ripshitandbust work.

Drag Moulding

2007-04-02T21:27:00.000+12:00

Did some further work on the drag mould today. This section is the finished dried plaster section. The avocado shape was produced by dragging a further ellipsoid shape over the semicircle section seen in the earlier installment. When dry, the semicircle section was lifted out to reveal the negative space inside. Overall a success but the actual dragging profiles need to be improved, currently the wooden profiles leave an unsatisfactory surface on the plaster sections. I suspect cutting the profile from 3mm aluminium plate would be an improvement.

This is the shape that I'm attempting to end up with. It will end up being a 200mm section of this shape in wax, which will be invested in plaster/silica and cast in aluminium.
So once I get a satisfactory (read damn near perfect) section I will make a two piece plaster mould of it, cast two wax halves and join them together. Plenty to do here methinks.

Ingot moulds

2007-04-01T21:51:00.000+12:00

This was an experimental piece of formwork for producing sand/ ludo ingot moulds. The sand is packed into the box at the front, rammed tight and inverted out onto the sandbed. Voila! instant ingot moulds...well almost.
Trying to set up two sand forms next to each other like trying to build a house of cards. I need to able to set up a bunch of these forms quickly so that I can pour multiple ingots at one time. Next attempt I will build a board with a dozen ingot patterns on it.
All was not lost however, I found that PVA glue makes a really good sealer for these patterns. It dry's quickly and leaves a nice smooth finish to the patterns.
Another idea I have had for ingot moulds is to make the sand forms out of sand impregnated with sodium silicate and purged with CO2. With a bit of luck and care I might end up with a semi reusable ingot mould.

Metal Casting

2007-04-01T21:33:00.000+12:00

Woke up the other day and thought it was time to get serious about metalcasting. It is really my first love in art and after five years of dicking around I want to do something useful with it. This is the furnace I built at school out of an old oil drum. It is lined with Kaowool ceramic fibre refractory.
The kaowool works far better than any of the castable refractories I have used in previous furnaces and weighs almost nothing. The series of images from this days casting are on my Picasa site http://picasaweb.google.com/greggspen along with the Honeycomb Sculpture that was the result of the days efforts.
The kiln needs some refinement yet. I want to modify it so I can melt down large peices of scrap aluminium etc into ingots.
I think the kaowool really needs a coat of Laitite refractory cement to protect it longterm and improves its heat reflection properties. The burner is a pretty inefficient design so I'd like too look at that and see if I can't improve on it.

Drag Moulding

2007-04-01T21:17:00.000+12:00

I am working a way of forming plaster shapes. This drag moulding set up is based on the way plaster extrusions were formed in the past for cornices and decorative mouldings for architecture.
The T shaped sections seen at the top of the image are profiles of the shape I wish to extrude. The wet plaster is spread on the glass table and the profiles are dragged against the backstop until the required shape is formed.
The results aren't totally satisfying yet. The profiles need a sharper edge as surface tension appears to affect the way the extrusion forms. I think the consistency of the plaster is pretty critical so I need to do a range of experiments and record the results to find the correct mix of water and plaster.

First Post.

2007-04-01T20:55:00.000+12:00

I started this blog as an easily accessible record of my work at art school. The bulk of imagery is located on my picasa site: