Greetings, I see that there are several high density (ie., from 6 to 30 lbs/cubic foot) urethane foam products available, which are used to do industrial prototyping, and can even be used by sculptors! (except where prohibited by law). Unfortunately, they are available only as very ponderous, and expensive slabs. The thought of just making my own crossed my mind, but apparently, the process requires the components be mixed in vessels capable of resisting the high pressures evolved, and a mayonaisse jar just won't cut it. I would appreciate hearing from anyone who has used these products, and their reactions. Bonus points to anyone who can recommend a distributor who will condescend to ship volumes of less than say, four cubic feet.
Much Obliged, Ethan Gross
I have used normal low density stuff to build cores for sculptures. Sometimes I work with clay on urethane kernel. The urethane kernel works as a support and reduces weight of the clay model. It is rigid, so the clay tends to crack and/or peel off when it shrinks during drying. One can prevent this by adding a layer of rags or newspaper around the foam.
Some works I have finished with fiberglas or other composite plastic. In such use one must insulate the core carefully, either with latex paint or easier by a layer of fabric soaked in dispersion glue.
You can look samples at www.netti.fi/~laurleva/
- lauri journeyman of sculpture
Ethan, Try the yellow pages under Insulation, Dow makes a blue foam board in various thickness'. I've used this material alot and find it suitable for modeling and if layered and painted will work for structural pieces.
Douglas E. Gabriel
[I've played around with samples of this stuff. It carves very easily, and is tough enough to hold a sharp edge, without the annoying 'feathers' that cling to wood as it is carved with a bur. The two brands I dealt with are Renshape 450 by Ciba-Geigy, which is a reddish color and costs $484 for each 4'x 16' x 60' board, and Polyshape from BJB Enterprises, which was considerably cheaper: $133 for a 4'x18'x 96' board. They worked more or less the same, although the former may be a little stronger and less porous. These prices don't include shipping, however. The Renshape is a bit too costly for me, but I was thinking of sending off for some of the Polyshape- would you like to split an order?]
UNITED ARTWORKS- Sculpture, Jewelry, and other art stuff http://unitedartworks.com http://www.computersculpture.com for 3d design tools
Andrew, Could you give me an idea of polyshape's density? I received a sample pack of various foams from Goldenwest Mfg., (mighty expensive) and found that 15 lbs./(ft.)*3 is just about my minimum so far as feel, and workability. What are you intending to use it for? Since you are involved in some CNC type of work, have you tried it as a model for burn-out? I would like to use it as a 'sketchpad' for wood carvings, and as a finished model for subsequent molds. Perhaps, one density is not suitable for all applications, but I would be interested to hear what you think.
I haven't seen the stuff you're talking about (which sounds awfully dense) but it sounds like you're looking for something that carves reasonably well.
After a terrible time carving some salvaged pink insulation foam for an armature. I've been looking for alternatives. Right now I'm playing with some of that green foam florists use for arranging fake flowers. I got 5 blocks, 3 in. x 4 in. x 8 in. for about $3 Canadian at Michaels (the craft store). Its pretty fragile but you can carve it with a knife - actually just rubbing it with your fingers will remove the stuff. Do it outside as it makes a lot of dust. I'm using it as an armature so I sealed it with Elmers glue and I'm covering it with Bondo. Anyway, maybe this stuff would meet your requirement for 'sketching' ideas. You have to admit its a fairly cheap alternative.
If you have a source for the foam used to float boat houses, it works pretty well. For large sculptures I get the foam 3' foot thick 4' wide 8' long. I use my welder with a 36' bronze rod between the positive and negatives rod holders, Then turn up the transformer just a little and use this to cut the block the way I want it. You can really sculpt the foam, it cuts like butter with heat, and it doesn't crumble like it does when cutting it with a knife. I use an electric soldering iron with special tips I have made from a #10 gauge copper wire. You can make what ever cutting tool you can think of for the soldering iron. The soldering iron works well in doing the finishing work on the armature, and is very clean. After the armature is
finished I paint on a hot coat of wax so the clay I use will stick to it
and it also keeps my clay clean for future use.
If you try the welder trick, be careful not to get the rod red hot, because you can set the foam on fire. But low heat works fine. My soldering iron doesn't get hot enough to set it on fire.
If you would like to see some of the sculptures where I used the foam armature, go to my web page at. 'http://www.ipa.net/~mgann/'
Hope this helps.
John& other foam workers,
The green foam used by florists, I understand from other sculptors, can be very toxic - I would try to get a copy of the MSDS if you are ever going to use a hot wire or knife to cut it. A bit safer is the 'Dow blue' foam insulation that comes 1 to several inches thick. Good luck.
you can buy high density urethane foam in liquid form & mix it yourself; it works great & is not toxic (unless you drink it); you can mix & pour whatever volume you wish for custom sized slabs. Smooth-On makes a range of foams called Foam-iT! - there are 3 lb., 5 lb., 8 lb., 10 lb., and 15 lb. densities - all of these products come in quart kits, gallon kits, 5-gallon kits, & drums.
I have encountered numerous sculptors who have used these products quite successfully to pour their own slabs - most notably I have enocuntered is Frank Stella.
Here's a link to these products if you're interested: http://www.smooth-on.com/Rigid-and-Flexible/c10_1122/ index.html