Relief casting mold

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Don Burt
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Relief casting mold

Post by Don Burt »

I will be doing some frit casting for a largish stained glass piece. It will be tree limbs. Lots of limbs. I have done this before by making a clay positive: Roll out the clay into a thin tile, cut out the tree limbs, cast the thing in plaster/silica, then use the plaster mold for frit casting. One and done. It's a lot of work. I was wondering if instead I could throw money at it? Can I buy some sort of refactory product into which I can carve out the tree limbs in relief, coat with kiln wash, and then cast frit into? Or can I cut out tree limb shapes with a razor knife out of some sort of blanket and cast into the cookie mold onto the kiln shelf? I'm looking at my bookshelf and thinking that somewhere between Lundstrom, Halem and Walker I could probably find some suggestions. But I've typed this much, so there it is. I'll look through Brad's book and If I find anything, I'll reply.

'Refactory' is flagged as a spelling error on this site. Of all things.
Don Burt
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Re: Relief casting mold

Post by Don Burt »

Here's an example from ...my god!, sixteen years ago! It's a pain in the neck and I don't need to worry about the texture of the surface, I can paint the textures I want.
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Ed Cantarella
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Re: Relief casting mold

Post by Ed Cantarella »

[quote="Don Burt"'Refactory' is flagged as a spelling error on this site. Of all things.[/quote]'Refractory :mrgreen: Bullseye - now THAT is a mysterious flagging. :lol:

Bullseye
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Don Burt
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Re: Relief casting mold

Post by Don Burt »

I didn't see the missing 'r' until Edpal247 pointed it out, even after a spell check on the browser, in which I may have spelled it correctly, but maybe not, because the results would correct it for me. Maybe I've never known about that 'r'. I'm not surprised or too concerned, but maybe I should get a tracking device to wear on my wrist for when I get lost.
Jenna
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Re: Relief casting mold

Post by Jenna »

Sounds like a cool project. Are you looking to cast just the tree limbs? Your 16yr old photos show what looks like some landscape included with the trees. Assuming just tree limbs.
Have you considered KL board? I bought some years ago to experiment with when I was thinking of doing a woodcut type relief casting. My hope at the time was to use the board as if it were a linoleum and use Lino cutting tools to carve into the board. Never did do that project and the boards are still wrapped up and sitting in my studio. I can do a smallish experiment for you tomorrow, at least the carving part...
Anyhow, that's the first thing that came to mind as a non-plaster alternative.
I would trade my kingdom to never use plaster again, but my mold designs are so intricate that only plaster will do.
JestersBaubles
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Re: Relief casting mold

Post by JestersBaubles »

Are the limbs too fine for a flexible silicone mold (that you then use to create the plaster)? At least you wouldn't have to redo the clay over and over.

What about creating the casting mold from clay?

Have Brad CNC something for you (I think he is the one who bought a CNC several years ago...). I'm not certain of the size that could be run.

Dana W.
Don Burt
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Re: Relief casting mold

Post by Don Burt »

Thank you for the suggestions. I think all of them would work. I'm leaning toward getting some 1/4" thinfire from our local Bullseye retailer, if they've got it. I see it for sale in the Bullseye catalog. There's quite a bit of discussion in the archives here about making wafers. I'm looking through that, but I'd like to work a little thicker than the typcial wafer.

Not thinfire... what I saw was this stuff:
https://shop.bullseyeglass.com/tools-su ... -long.html
Tod
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Re: Relief casting mold

Post by Tod »

Is the Bullseye fiber paper reusable?

When I read "fiber" and think about carving, I envision fibers getting in the way of fine details and material removal.
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Ed Cantarella
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Re: Relief casting mold

Post by Ed Cantarella »

Tod wrote:Is the Bullseye fiber paper reusable?
When I read "fiber" and think about carving, I envision fibers getting in the way of fine details and material removal.
Seems to be many way of referring to the products. I personally think of anything thicker than paper as "cloth". Play with 1mm, 2mm and 3mm fiber "whatever" a bit. Treat it like felt - press it down a bit if you want. You can even apply some boron nitride or mold rigidizer to it to mat it down (kiln wash is a bit dicey, mold ridigizer is probably best for most situations). Just as it is, leaves a pretty nice impression, up to a point. Just think like: if I was using felt that didn't melt, would this detail be good enough for what I am doing? You'll be amazed - no fuzz or fibers are visible in your glass. But the texture is.
*Please cut in front of an exhaust fan, HEPA filter or at least wear a good respirator - it gives off quite a bit of fine dust just cutting with the sharpest scissors.
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Buttercup
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Re: Relief casting mold

Post by Buttercup »

[quote="Don Burt"]Can I buy some sort of refactory product into which I can carve out the tree limbs in relief, coat with kiln wash, and then cast frit into? Or can I cut out tree limb shapes with a razor knife out of some sort of blanket and cast into the cookie mold onto the kiln shelf?

Don, Is it the plaster cast or shaping the clay that is putting you off? Some time ago I bought some special modelling plasticine, thinking it would handle less messily than clay.......and, no, there isn't any more to tell. It's still unused. I plan to make the relief positive, cast it in plaster, then use the intaglio design in the plaster as a receptacle for the frit or a shallow kiln carving. That wasn't very helpful, was it? Just suggesting plasticine instead of clay.

Was it the the clay and plaster cast method that you used for the relief piece you made some time ago with the fairy in the tree roots? Love that! Jen
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Re: Relief casting mold

Post by JestersBaubles »

Buttercup wrote:Some time ago I bought some special modelling plasticine, thinking it would handle less messily than clay.......and, no, there isn't any more to tell. It's still unused. I plan to make the relief positive, cast it in plaster, then use the intaglio design in the plaster as a receptacle for the frit or a shallow kiln carving. That wasn't very helpful, was it? Just suggesting plasticine instead of clay.
I bought some of that too, and yes, it is sitting unopened/unused on a corner of my work bench. Every once and I while I consider unwrapping it :mrgreen:

Dana W.
Ed Cantarella
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Re: Relief casting mold

Post by Ed Cantarella »

Dana - try out the plasticine clay, you'll probably like it. No drying, no cracking, no waiting. I worked with a bronze sculptor for about 7 years and that was all we used.
Suggestions: most manufactures make a hard(#1?), medium(2) and soft. Soft is really too soft, medium is very nice, hard is tiring to work but holds fine detail . If the clay seems too stiff, put it in a plastic bag and drop in a bucket of warm water - smooth and creamy. Conversely, you can chill your finished item slightly if you're worried about losing detail while applying your release or if it just seems too soft.
Use open tools for the carving so you are removing clay - solid tools just push it around and make a mess. Plus the open ones are great for carving KL or vermiculite board.
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Release spray(or melted vaseline brushed on), and you are ready to mold over it. When you are done you can take one of the tools and scrape off the surface of the clay and recycle it for bulking up your next project at very least, using some fresh for the surface.

If doing something larger and vertical on a board, draw the outline of your item, then attach some hardware cloth(large screen) to the board with screws staying inside your drawing - press the clay into that and no more worries of your work plopping off. :cry:
edit: Many contain sulfur so don't rub your eyes or face - won't blind you(?) but is quite irritating to tender areas. 8) Chavet brand costs more but no sulfur. Some folks say sulfar bearing plastina creates problems with RTV not setting up. We never had problems - thin layer of melted Vaesline brushed on as a release. [bit OT] I think many people screw up on RTV mixing thinking they can do by volume. Manufacturers specify you do it by weight because they don't weight the same. Close but not close enough to screw around with eyeballing it. At $100/gallon+
Last edited by Ed Cantarella on Thu Apr 05, 2018 10:24 am, edited 1 time in total.
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Don Burt
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Re: Relief casting mold

Post by Don Burt »

I've always used plasticine for making relief molds. I don't feel real skillful with it. I've done three or four stained glass windows with relief pieces that made that way. I remember rolling it out spending time tooling it a bit, then using a heat gun to smooth the surface, using those little syringe like extruders to make ...extrusions...I guess it got done OK. It's not on my bucket list of media to become skillful with.
linn keller
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Re: Relief casting mold

Post by linn keller »

barbara cashman is selling Silkemat - a new(?) refractory fiber - on her site that she says doesn't shed, break down like conventional fiber, smooth cuts. cut with non-carcinogenic, don't have to wear mask, etc. looks clean and neat. can be rigidified (she has rigidizer for it, too). she has a couple of videos demo'ing use. haven't tried it myself yet but definitely interesting.
linn
linn in deep deep south texas
Ed Cantarella
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Re: Relief casting mold

Post by Ed Cantarella »

Don Burt wrote:I've always used plasticine for making relief molds. I don't feel real skillful with it. I've done three or four stained glass windows with relief pieces that made that way. I remember rolling it out spending time tooling it a bit, then using a heat gun to smooth the surface, using those little syringe like extruders to make ...extrusions...I guess it got done OK. It's not on my bucket list of media to become skillful with.
I had to watch THIS guy work for almost 8 years ( I was his fabricator, general helper). I'll never be 1/2 that good, but great learning experience.
:idea: Put parchment paper(not wax paper) over the clay, makes rolling a lot easier. Obviously roll up on blocks the thickness you want. And yes, a hand-crank pasta extruder works really good for creating sheets(jacket lapels and collar on the attached image were done that way.) *I made the bow - it's wood. :lol:
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