View Full Version : expanding foam on armature
10-01-2005, 03:00 PM
I am trying to find info on how the process of putting expanding foam on an armature so minimize the amount of clay you have to use for the figure. I'd like to know if there is anything I can use besides the stuff in the can at the hardware store? I'm not getting the results I want so far.
10-01-2005, 03:16 PM
I've never tried a tin foil filled armature, but after seeing this large dragon sculpture, might give it a try. Could recycle the wads of foil for other armatures.
10-01-2005, 09:46 PM
gotot a homedepot look for a spray foam insilation. dont get the "foam-it" canned stuff there is a special canned foam with disposable triggers they sell, i think its called "interfoam" its not too expensive, they should know about it there. if not the foam-it stuff will work. spray it over your armature, let it dry completely, then use a sharp knife to carve the shape be fore you add clay.
this stuff will not come off clothes floors anything so be very careful, and do it outside with goggles, if it clogs it can be a mess when it shoots out. make sure to keep the nosels clean.
10-08-2005, 05:39 PM
Thanks for the advice. I will try to find the stuff at home depot. I tried the Great Stuff large gap expanding foam, but it was spongy when it cured. It may work, but I'd like to find something that could be carved and/or sanded before applying clay.
10-09-2005, 12:38 PM
they do make a great stuff that has low expansion, i forget the type, but the brand is great stuff, that wont stay as squishy.
10-09-2005, 02:59 PM
there are a number of foam products available that are two part, they cure faster than the canned stuff, and usually hold up better. Additionally you can get different density foams, uaually 2#, 4#, 8# and 16#, but there are others too. That is the way to go, because then you can carve it , and it will stay stiff and in shape. Also most of these foams are very rapidly curing, so they expand in like 90 seconds, set in about 3 minutes and are usually ready for 'decasting' in 8-10 minutes. Some of the specially designed carving foams do need a night to fully cure before they get thier best carving properties.
From what you describe, that's the stuff you need.
If you are putting it on wire armature, then you will need something to contain the foam(because these foams are 2 liquids that must be rapidly and thoroughly, then poared before expansion).
I have a friend who has done this, by poking holes in plastic bottles(gallon, 2 liter, 1 quart, etc depnding on size needed) and using that to hold the foam. Make sure and use the proper release on the inside of the bottle, that way cutting it off won't destroy the foam. Then you can carve away!!
(a little bit of foam, saves a lot of clay costs.....)
Best of luck.....
10-09-2005, 10:29 PM
check link here (http://www.sculpture.net/community/showthread.php?t=2004)
10-10-2005, 07:38 PM
yeah that box foam is perfect!, but the liquid two part will work dont get more than a 5lb density or it wont expand enough to be useful, and will be too hard to carve. If you are in a pinch take a large zip lock, mix in A and B, shake it up, then once it starts to foam cut a small corner like a cake icer, then go over your wire. that worked well when we ran out of box foam and were under the gun at Universal.
SAFTEY- not to be a nag, but remember any A|/B foam will not come off skin, out of clothes, rugs, or eyes. Get MSDS sheets
wear a respirator with a chemical cartridge , gloves and eye protection, this stuff can be deadly, and plain ole' nasty. always keep an eye wash handey and a fisrt aide kit.
10-11-2005, 12:36 PM
I have tried smooth-on's expanding foam but I had a bit of a problem. You know that saying about learning from your mistakes? Well I thought I would try out something that I read about wrapping a persons torso in plaster bandages then using that as a mold for expanding foam. I put a mold release in the form but it didn't totally fill in the gauze. When I poured in my foam it expanded into the gauze and now I have a very nice torso with plaster gauze that can't be removed unless I get out a chisel and hammer. OOOPS! I guess that's my mulligan on that technique.
I am now experimenting with making some foot forms by taking a pair of shoes and sticking a bread bag in it and filling with the "great stuff large gap" foam. I don't need detailed toes as I'm going to be fabricating shoes over it. I definately would prefer something that doesn't take days to cure up. I am going to find out if the spray foam company has a sample size.
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