New to foam sculpting - need advice

[digital dawg]

Trying to work out some demons that have been keeping me awake at night. I need to make a sculpture about 2.5' x 2.5' x 5' out of polyurethane. I was thinking of building a box in these dimensions, filling the box with great stuff foam, and then sculpting from there.

The sculpture is not going to be very complex at all and is symmetrical. I want to have a mould created from the sculpture so that I can reproduce it with polyurethane foam again and again. What will be the best type of mould to run off polyurethane sculptures from? Will vacuum form moulds fit the bill?

Also, is there a cheaper alternative to great stuff foam? It's $6.50 a can at Home Depot and for something this size I'm going to have to use quite a few cans.

- DD

[clonesix]

DD,

I too like to sculpt in polyurethane foam. I prefer to purchase the foam rather than use the pourable stuff and create my own foam block.

I purchase mine from an insulation company that makes it in 3'X3'X4' and runs it through a bandsaw to size. If you don't have a supplier in your area, and can't find on in the yellow pages, try using a few of these: http://www.vandykestaxidermy.com/sea...olor%5D%5B%5D=

You can buy this stuff in 2#, 4#, 6#, 8#, 12#. The higher the density, the more detail you can carve into it.

What do you want your finished piece to be? That will determine what type of mold you need to make for it. Foam has a porous surface, and if you want to mold it directly, you will reproduce that texture. It can be surface coated to a smooth finish with some extra work.

[digital dawg]

Thanks clonesix. I really have no idea where to begin in mold making and casting, but it's really going to be fun learning the process. I'm a carpenter by trade, so I'm mechanically adept and feel confident I can learn to do this project the right way.

The finished piece will be a giant 2' x 5' pencil. I'm guessing I'll have to do this as a two piece and glue it together? Or perhaps I could make two half molds, clamp them together, drill a large hole in the top to pour the foam into, which would also allow the overflow to pour out when the foam expands? The foam itself doesn't have to be completely smooth. I can put a thin coat of vinyl spackling or drywall over it and work that out smooth.

Based on what I want the finished piece to be, would I need a rigid mold or something like a silicone mold?

[clonesix]

A pencil? A regular #2? That is a simple enough shape.

A hexagonal prism shape, sharpened at the tip, and rounded at the other end for the eraser.

I don't see any reason that this can't be done in EPS (expanded Polystyrene). There are several places that will make you a six-sided prism shape out of EPS and a hot wire. Then all you would really need to do would be to sharpen it.

The EPS leaves a rough surface, but to finish it, you need a non-solvent based surface coat. Try here: http://www.fxsupply.com/materials/foamcoat.html

The molding and casting is another can-o-worms. DO they need to be foam? Can they be hollow resin cast? Why is your unit cost budget?

[GaryR52]

I've also worked in carved foam, though polystyrene instead of polyurethane. I finished the surface with a few layers of acrylic modeling paste, followed by acrylic paint. This was for indoor display, only, obviously.

What I'm wondering about is what direct modeling compounds I could use in place of acrylic modeling paste, that would produce a weatherproof shell that could be displayed outdoors. I've looked into three materials: Design-Cast 66, Forton MG and Winterstone. Winterstone is the most economical and consists of a powder that mixes with water, while the other two use a polymer component as a binder material.

My main question is, how salable would such a piece be, in light of the fact that most collectors are looking for pieces executed in traditional materials such as bronze and stone? I get the impression that materials such as those I've mentioned above are still regarded as amateur or hobbyist materials and are not generally accepted by galleries or collectors as serious sculpture materials.

Gary

[Lorax]

I sculpted a large dog for a client out of urethane foam. I ordered pour- foam, a two part mix that turns into the foam when mixed ( and poured ). I had details so I bought it in an 8# density, but for such a simple shape you could use a 2# which would reduce cost. pouring your own would also reduce shipping cost. You will still need to coat it, but I would stear clear of vynil spackle. Winterstone would be a good/low expense way to go, but it is aa little more labor intensive than some others. sculpt.com has some various foam coating materials for various uses. I had to make one that had to withstand the elements so I got a compound from IndustrialPolymers.com called Styro Spray. It is a two part brush or spray on urethane coating that can be used on polystyrene or urethane (or most any other bases). I was very pleased witht the results, but it was still fairly labor intensive. I am not trying to sound like a comercial, but when I was looking for sources, it took me a lot of searching to come up with the right places to get supplies. hope this helps

[eyeballjohn]

Hi, I have made plugs using both spray on foam and blocks of foam purchased at HomeDepot or any other Home supply store, they come in 3 inch width by 8feet long, or you can buy pour foam from boat supply companies, if your going to make a mold out of your foam piece just make sure you coat it with something that will seal it and protect the foam from melting, a cheap sealer I use is common exterior house paint, once you coat the foam with paint and it dries yuo can cout it with other primers or fiberglass, you can mold with fiberglass or use an RTV silicone, there is a thread on this site about sculpting with foam on this site that might give you more info. on this, you can check out my site at WWW.eyeballjohn.com for some other info. on this.

[hotwired]

Here is a pencil, among other varied EPS foam sculptures:
http://hotwirefoamfactory.com/custom...tart_garyv.htm

Most studios are switching to EPS foam and hotwire foam cutting tools rather than using the old polyurethane foam. Polyurethane foam is environmentally toxic and decomposes over time. Alhough EPS foam takes up landfill space when dumped, it is recylclable and gives off no toxins. Also, EPS foam is already a recycled product that is leftover from refining crude oil to gasoline. A dust mask should be used when sanding EPS foam, but it is non-toxic when cut with a hot wire tool.

Coatings and glues with no solvents must be used on EPS foam.

You will find tons of foam cutting, foam gluing, and foam coating tips in the foam artists' Projects and Gallery.

[GaryR52]

Nice pencil. Reminds me of Claes Oldenberg. By the way, I once lived in your neck of the woods, when I was stationed at Vandenberg in the early seventies. I can't believe the housing prices in Lompoc, these days!

Here are a few views of a piece I did in EPS, back in 2005. It's remained untitled from then until now, but I am herewith titling it Homage to Moore, as that's what it is; i.e., an homage to my favorite sculptor, Henry Moore.

I built up a block from sheets, using Elmer's Glue to cement them together, then, after carving, I applied a couple of layers of acrylic modeling paste, sanding between coats. I then painted it with three colors of acrylic paint (first, black, followed by a darker and a lighter green), applying the paint straight from the tube, wiping it on with paper towels.

I'll have to reduce these to post them, but I wish you could see the surface details. The pitting, scarring and tool marks in the surface bear a strong resemblance to those Moore left in his own works.

P.S.: This is 15 1/2" x 11 1/2" x 6"

Gary

[gmet]

nice job gary.