Stop Motion Animation Forum Archive











Posted by Joey Armario (Guest), on 2001-03-17 12:13:47

Foam Used For Sets

NOTE: the following messages have been transferred from the original Message Board Joey Armario User ID: 1766884 Oct 9th 10:56 AM Hi. I was wondering what type of foam was used to make sets. Where can I find some of this? I know that it is good for sculpting on and giving details too. Thanks! Nick H User ID: 0701364 Oct 10th 8:47 PM You can use polystyrene foam, which is white and comes in sheets and blocks. You can carve it with a sharp knife. Or there is rigid polyurethane 2 part foam. You mix a thick clear liquid with a thick brown liquid, and it swells up into a light brown foam in a couple of minutes, and sets hard about 5 or 10 minutes later. It gives off toxic cyanide gas while mixing and expanding, so use outdoors or with really good extractor fan system. It resembles a lava flow, great for rocks and caves, and can also be carved easily (wear mask!). There is also a 1 part aerosol can version that you can find in hardware stores, it's used for filling gaps. Neil L User ID: 2087514 Nov 21st 0:41 AM Modeling with Balsa Foam is another option. It comes in different strengths and can be carved with beautiful results. They have a web site if you need more information. I might caution you though to wear a dust mask when using these different foams as the dust is not good to inhale. Marc Spess User ID: 0449874 Dec 2nd 7:28 PM A foam that I like to use is the blue foam you find in hardware stores. It is a solid dense foam that you can cut easily with an exacto knife. It is sandable and you can paint it with everything but spray paint. It comes in 8' by 4' sections and can be anywhere from 1/4 inch thick to a foot thick. They use it on houses where you need a sound barrier I believe. I have seen carpenters apply it between siding on houses and the interior plywood. It usually cost 7 - 8 dollars US for a sheet. I have used this foam to make trees, rolling hills, and brick walls. Tom Brierton told me that when he made his last film which was set in a castle, you can take a mini torch and melt away a stone pattern with it. But he also advised that it gives off some nasty toxic fumes, so your best bet is to use sand paper folded in half. Take the folded sharp edge to cut grooves and texture the foam.

Posted by Sock Puppet, on 2003-04-14 11:02:43

I was reading up on a specialFX book, and they talk about using the polystyrene that you guys mentioned earlier in this post. I have used blue builders styrafoam before, and it is somewhat carvable. Is the polystyrene easier to use for sanding and carving? What kind of mask should be used when sanding or burning various types of foam??? and Nick, how good is this balsa foam? is it a similar density as balsa wood? where can you order these foams on-line? i have been thinking about using blue foam for my ground layout, with rocks and hills etc.. then i was going to seal it with something like primer, or gesso. then paint it, or add sand texture with elmers glue in a spray bottle. or i was going to simply plaster over the foam, then paint it, and then add sand. any tips would be appreciated. I would like to use my heat gun to melt some of the foam, but i have done this once and i got some nasty fumes. what kind of mask is good for toxic fumes? thanks _josh

Posted by Antony, on 2003-04-14 19:03:34

Balsa Foam is great but you would mainly use it to carve structures like walls and a building facade, etc. Being more expensive than some of the other mentioned foams Balsa Foam is worth it as you can get excellent detail.

Posted by Nick H, on 2003-04-14 19:16:01

I don't know what Balsa Foam is. I've used white polystyrene foam which comes in different densities, and can be carved with a sharp knife and sanded with rough sandpaper. Probably similar to the blue stuff. It comes in big blocks, so not practical for mail order. (It can look good for rocks or stone carvings, but is no good for ground that you need to put tiedown holes in, for that you need a hard shell like plaster and chopped strand fibreglas matting over chicken wire.) Urethane sticks well to styrene (to anything, really) to build up more texture or to stick a couple of styrene blocks together. Either the 2 part mix (toxic fumes while foaming) or the aerosol can gap filling type will work, and if it foams up too much it's easily carved back again. I think you can buy rubber masks with different filter inserts for different fumes or particles. Otherwise, work outdoors standing upwind of the foam when burning, or outdoors with a fan if there isn't much wind.

Posted by Sock Puppet, on 2003-04-16 11:15:42

thanks yet again nick. the original nick that mentioned the balsa wood must have been another nick. have you or anyone else ever used a foaming gun for spraying down a light layer of textured foam on a set floor or something else? _josh

Posted by Antony, on 2003-04-16 20:57:49

Nick H If you want to see what Balsa Foam is like go to my website which has examples and Australian prices for it Antony

Posted by Nick H, on 2003-04-16 21:50:55

Thanks Antony - looks like a good material. Is there a Melbourne supplier, or would I have to have it shipped? It could be the right material for some strangler fig roots I'll need to sculpt for my next proposed short, The Fig's Embrace. The original mention of Balsa foam in the old posts above appears to be by Neil.

Posted by Sock Puppet, on 2003-04-18 11:25:55

thanks Antony. Do you or someone else know of a US supllier? It looks to be a very good material. How do you work with it? Do you dremel it? cut it with an exacto knife? sand it? anyone have any tips on working with it? _josh

Posted by Strider, on 2003-04-18 14:06:07 Micro-mark also carries it. You can carve it, or simply press shapes into it with any sort of tool. Then you harden the surface with gesso or water putty or something.

Posted by Sock Puppet, on 2003-04-21 07:08:02

thanks mike! i want to try this stuff. _j

Posted by Sock Puppet, on 2003-04-22 07:44:47

i take it nobody has ever heard of or used a foaming gun before? _j

Posted by Nick H, on 2003-05-01 00:26:06

3 or 4 years ago I saw a brochure for a foam spraying kit that must have included the 2 part urethane goop and some sort of gun, I think it was around A$350 (maybe US $175) for the smallest kit. For really big jobs there are companies who come and spray your forms with foam, like for a full size cave set. Never had the budget or the need for the spray kit, usually get 2 litre cans of each part and pour it over the form or spread it on with a stick.

Posted by Sock Puppet, on 2003-05-02 14:37:20

thanks nick. i suppose it is probably only handy for very large sets. the pic i saw WAS a large set. _josh would be kinda fun though :)

Posted by Nick H, on 2004-08-09 00:01:18

Thought I'd dredge up this old thread, because I've just taken delivery of a 2-part urethane foam spray kit. It's the Versi-Foam System 50 (the smaller kit is the system 15). I think it expends to 1.5 cubic metres at ideal temperatures. (Don't know what the "50" is, maybe 50 cubic feet?) I'm doing some big "stone" garden objects, and mixing small amounts of foam at a time was taking forever, and flowing where it wanted to, not where I wanted. It comes in 2 pressurized metal cylinders, with 2 hoses that join together at the mixing nozzle. It cost A$1,083.00 in Australia, which would be about US $700, probably less in the US where it is made. The smaller kit is a bit over 1/3rd the price. I'll post results here after I've tried it, probably over the weekend.

Posted by m and j, on 2004-08-10 13:00:33

Hey guys, what's gesso? How does it work? You mentioned using it to harden foam for a set, will it work with any foam? thanks.

Posted by Marc Spess, on 2004-08-10 16:07:15

Gesso, I believe is just plaster, water, and I think it has a base of acrylic or something to that matter. You know, the secret ingredient that gives it it's name. Maybe one of the artsy guys on here would know exactly what it is. The main purpose for it is to seal canvas before painting it. But you can buy plaster just for foam that is smooth or textured with sand. We sell it on the site, it works real well and is fairly cheap. Marc Visit:

Posted by Sock Puppet, on 2004-08-10 18:44:56

BTW, that blue builders foam is polystyrene, not styrofoam. styrofoam(whitestuff) is usually made up of little balls, and crumbles easily. I dont recommend for set building. The blue/pink insulation foam, or blue builders foam as i always called it is much tougher, and is easy to work with. As previoulsy stated it can be carved, sanded, and cut and broken with a utility knife. I have also cut and shaped it with a hot knife before, which is great, but is very stinky. Hell, i have even lit this stuff on fire before ;) But when it comes down to it, you can light just about anything on fire. For some reason some of this polystyrene actually says Styrofoam onthe side of it, even though its actually polystyrene. Probably the same stuff, only the insulation stuff is just pressed together tight, so its much tougher and denser. It is confusing when it says styrofoam on it, but is listed as polystyrene. I have seen this multiple times. And another difference to watch for is some contact cements say its ok to use with polystyrene, but not styrofoam. Just remember NOT to get the stuff that crumbles. If it bends a bit, and isn't brittle, its probably good to use. And so far i have only seen the styrofoam crumbly crap in white, and the good stuff is always colored like blue/pink.

Posted by m and j, on 2004-08-10 22:23:40

Thanks for helping a newbie Marc. So can you use foam specific plaster as a substitute for gesso? By the way, (I'm sure you hear this a lot) but your site is SICK! It's helped me tons.

Posted by Marc Spess, on 2004-08-11 04:11:49

Hi M & J, To answer your question - I don't know if you could use foam plaster as gesso. I'm thinking gesso is purposely made for the painting task. It couldn't hurt to try I guess if your feeling experimental :9 Marc Visit:

Posted by Antony, on 2004-08-11 07:40:55

Gesso is like a sealer and primer type paint. Gesso is one of those names that also applies, these days to many different types of painting grounds and sealers. The traditional Gesso was made from whiting and glue size. These days gesso is usually an acrylic based compound designed to create a sealed and slightly absorbent surface ready for painting. When I have time I enjoy making my own grounds for painting oils on canvas, I find that making your own is often much more rewarding and just plain better than slapping on a tub of acrylic factory made stuff. I am not sure if the foam plaster is going to give you the desired effect, I guess it depends on what you are trying to stick to and paint it with. Antony

Posted by Sock Puppet, on 2004-08-11 10:22:08

The first time i ever used Gesso, was back in middle school doing silk screening. Then i used it for prepping painting surfaces and such. And now i use it for lots of stuff. It is very similar to an acrylic primer, and serves the same basic seals and preps for painting. Not sure which one is better for what etc.. I think the qulaity of Gesso is nicer, and it adheres to various surfaces. I use it on plastic and other prop materials before painting, but primer works too. Maybe the gesso is a bit thicker and absorbs paint more? We used it to prep the tops of the animation tables as well, but make sure you mix in a little brown or grey, so its not white. Otherwise when you drill your tie downs, you dont get over powering white dust everywhere. Ditto for plaster. And more important for plaster if its thick.