Styrofoam for carving?

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batfan10

Sr Member
I've been thinking about making ice statues like in Edward Scissorhands except out of clear resin
edward-scissorhands-06-630-75.jpg


I think Styrofoam would be the way to go as there would be too much clay involved but I want something that would be a smooth texture. Anyone know what kind of Styrofoam I'd need and perhaps where to get it?

Thank you so much!
 

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Nwerke

Master Member
RPF PREMIUM MEMBER
Avoid expanded polystyrene foam (the kind made with the little beads). You might do OK with closed-cell polystyrene foam as it is much easier to carve to a smooth surface.

You would definitely find a good medium density urethane foam a much better medium to work with, though. You should be able to obtain it from any industrial foam suppliers in your region. Polystyrene is really too soft for something large unless you're going to spend a lot of time engineering proper armatures.
 

PrimoOptimoso

Well-Known Member
RPF PREMIUM MEMBER
I don't know if it's polystyrene (I think it is, but its texture belies that fact if so) but green florist's foam is amazing to carve, specifically the "dry" kind - some florist's foam is made to be soaked for plant moisture purposes.

Its biggest drawback is that you have to glue up a bunch of bricks of it to get to any appreciable size. But once you have a big block of it, it carves wonderfully and can even be sanded. Hell, use a big drywall sanding screen and you can shave off lots of material rapidly, almost as fast as carving itself, before switching to finer grit.

Caveat: lots of fine scratchy dust. Take precautions.

And of course Nwerke is right about the strength and texture of expanded styrofoam.
 

Nwerke

Master Member
RPF PREMIUM MEMBER
No no, I mean rigid urethane foam. It comes in sheets or blocks, in a range of densities. As used by, for example, signwriters, to make three-dimensional letters for large signs, or cores for fibreglass statues, etc etc. It's not cheap either but it's really what you want for this sort of work, if you're going to avoid clay. It's the same texture as floral foam, but urethane rather than phenolic. Probably not as toxic, but check the MSDS.

Be aware that sculpting and moulding and casting on this scale is automatically going to be a laborious process and will require substantial cash outlays on materials and tools. It'll be messy and smelly too.

And that's assuming you already have the skill set. Double the costs if you don't, to account for errors while learning.
 
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Nwerke

Master Member
RPF PREMIUM MEMBER
The link you attached is for a company which makes hotwire cutting tools, not foam.

They don't appear to offer any actual foam, as far as I can see.

Was it the link you meant to attach?
 

Nwerke

Master Member
RPF PREMIUM MEMBER
Oh, sorry! I did look but my attention span and search-fu are clearly rubbish right now!

Yeah, EPS is one way to go, but the pics the OP posted suggest he wants to make long fragile parts like extended arms and the like. EPS is not good there as it is pretty soft stuff. Could be used, but would require an armature (support framework, usually metal).
 

danbakeronline

New Member
Nwerke is correct. For carving stuff that large, you're going to want to go with HDU (high-density urethane) foam. It's a closed cell, rigid foam with some real strength that won't bow or sag like open-cell foams would. And floral foam is just damaged too easily.

In large production houses, they'll order huge blocks of it. You could pour your own blocks with Foam-It 10, found here: Foam-iT!® Series Rigid Foam Product Information | Smooth-On

But it will be an investment for pieces that large. I'll give you a secret. I used to go around to any sign supply warehouses and ask for their HDU cover sheets. Every pallet has a "bad" sheet on the top and bottom they just throw away. Sign shops won't buy the damaged sheets, but for the small-time hobbyist, they're perfect for cutting up and gluing together.

If you go that route, glue them with Gorilla Glue, and be sure to use water. Gorilla Glue is basically urethane foam. Urethanes hate moisture, and foam up terribly when they get wet while curing. Gorilla Glue uses that property to have their glue foam out and grab onto surfaces. If you use Gorilla Glue, you'll just end up with a solid HDU block, and you won't see the "layers" where you glued it up as much.
 

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Nwerke

Master Member
RPF PREMIUM MEMBER
Well said, Dan. Ah, the scabbing for leftovers at industrial suppliers approach...I miss the good old days, lol. Also good for free coil springs, big pieces of styrene sheet (aka plastic card), offcuts of solder, you name it.

One caveat: if you end up grabbing much urethane that way, please keep in mind that you may wind up with different densities. Don't try to make a single part out of foam of different densities, it is a recipe for pain. :)
 

Laffo

Sr Member
Or you can use Pink Foam Insulation from any of the big box home stores. There's a ton of builds on RPF using it.
Laffo.
 

Ahura

New Member
The fancy HDU stuff is really nice. It's denser, and easier to get those fine details into. If you want to go on the cheap, use the EPS Pink/Blue Insulation foam they sell from Home Improvement stores. 4'x'8' sheet, 2" thick for $30 here in GA. It carves super easy, but really really fine details can be tough sometimes.
 

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Ozymandius

Sr Member
RPF PREMIUM MEMBER
I hope you got deep pockets, cause the cash you'll need for silicone and resin for even one of those sculptures will buy you a good used car.
 

Steamtech

Member
I just want to second the idea of using the EPS Pink/Blue Insulation foam. I purchase it from Home Depot for a few dollars per 8x4 sheet and just cut and glue the pieces to the size I need.

When the carving is done I slather it with Bondo and once that sets you can sand it to whatever finish you need (and also get much finer detail than what I've been able to achieve in the raw foam).

I really liked Danbakeronline's suggestion too and I'll be looking into that myself for future projects. Especially since I have a sample pack of the FoamIt sitting in my garage waiting for something to do :lol
 

Mostly Fantasy

Well-Known Member
RPF PREMIUM MEMBER
I get my urethane foam for work from ISO technologies- it comes in a variety of densities. It's heat/solvent resistant, and takes anything I've used so far to sculpt on top of. They're also the least expensive I've found so far. I recommend the 4 lb- you can get a very fine finish. For your purposes, you'd probably want to spray with a clear urethane finish prior to molding, like Chroma Clear.
 

Mostly Fantasy

Well-Known Member
RPF PREMIUM MEMBER
P.S. Super 77 spray is the adhesive I use if I have to glue scraps together- it's strong enough to hold while carving, yet doesn't leave a rigid line.
 

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