I bought a 36" square x 6" thick piece of 1lb. styrofoam to "play" with. I want to carve a scalloped seashell out of it. What kind of tools do I use to shape the three-dimensional ridges. I'm thinking my wood carving chisels will mostly bend this material instead of cutting it. I have a client that wants to have this shell mounted on a wall of his new building and then stucco over it so that it looks like a wall decoration. Thanks for your help
Posted by Glenn Taylor (Member # 162) on :
I think a set of rifflers, rasps, some emory boards and sandpaper would do the trick.
Posted by bronzeo (Member # 1408) on :
Jean, I believe Glen is correct, but some use a hot wire to cut and form with. I haven't tried this method, but I believe it is the way they cut pieces to size.
Posted by Arvil Shep' Shepherd (Member # 2030) on :
Did you say 1lb ???????? If so you can use grades of sandpaper or practically anything to cut it...it is VERY soft.... (You sand it like petting a mouse with a feather) I have used 2lb. in the past, and used a scrap of the same material to "sand" it.... Sorry for the above answer..I misread, I thought you were talking about URETHANE !!!!!! Good luck Shep'
[ June 29, 2002, 09:33 AM: Message edited by: Arvil Shep' Shepherd ]
Posted by Cheryl Lucas (Member # 1656) on :
Hi Jean,
An electric carving knife may be helpful to remove some of the larger chunks!
Cher.
Posted by John Arnott (Member # 215) on :
Jean, I have done this before. Start with a regular hand saw for fast rough shape. I bought a 4 1/2" grinder at Harbor Tools for $20 ! It works great with the wood sanding head. I also rounded a bunch of 3" thick styrofoam letters with it. It really cuts shapes out fast, yet enough resistance to "feel" the carving. I carved a big fish and a racoon out of styfofaom. Great fun. Enjoy
Posted by Mike Pipes (Member # 1573) on :
A rasp or coarse sandpaper will do the trick pretty easily. I've used this method quite a bit in the past for sculpting forms for fiberglass work, using epoxy resin instead of the usual polyester 'glass resin.
If you are going to paint it, you might have to coat it with something so the paints don't attack the foam (depending upon the paints you use.)
If you coat the whole thing with an epoxy resin, not only will that fill the cells but you can then use any kind of paint you like. Epoxy resin does not melt the foam. If you dont want to use epoxy, you can coat it with latex paint as a barrier coat, then find something else that will stick to the latex.
**edit**
OOps, just re-read what you posted about using stucco instead of paint.. nevermind. That's how all the houses out here are built though.. wood frame, OSB over the wall studs, styrofoam insulation stuck to the OSB, wire mesh over the foam, then stucco.
[ June 29, 2002, 01:06 PM: Message edited by: Mike Pipes ]
Posted by Dave Draper (Member # 102) on :
Hi Jean,
First, Styrofoam is a brand name and doesn't describe exactly what you are working with.
Expanded polystyrene is the white stuff made up of little beads, thus nicknamed "beadboard". It carves well with hot wire, saws, sandpaper, routers heat gun and even mineral spirits or enamel spray paints which "melts" the foam. Vinyl letters laid on this material and then melted weth a heat gun will creat some interesting effects.
Extruded polystyrene is the blue foam made by DOW or the pink version made by CORNING (pink panther people). This material is denser and stiffer and doesn't crumble at all like "beadboard". Different effects using the same tools listed above will result because of its nature.
Latex paints will protect these foams and they are extremely stable for out door use as long as human beings can't "pick" at them.
The way to really make your creations rock hard is to use the premixed concrete stucco that comes in 5 gallon pales and costs about $50.00 It is not just premixed concrete...its got some hi tech chemistry involved as it stays fluid in the pale but dries in minutes once it is spread out on a flat surface. A 1/16 of an inch spread is very impressive as far as durabilty and hardness is concerned.
I will stick my neck out and say that expanded polystyreene covered with Drivit signs are going to out sale and out preform lighted can signs and sandblasted signs in the next few years. They look like the buildings the sit in front of, they are easy to build and the materials cost less and these signs just look darn good!
It would be a good time for all of us to learn what EIFS means. Posted by Eric Barker (Member # 2972) on :
Dave, In my former life, in the construction field, I saw alot of Drivit going up. It has many good qualities. I do remember one instance though, where birds pecked large enough holes in the side of a hospital, to make themselves a nest. The Drivit sub was not amused, but the rest of us got a good chuckle out of it.
Posted by Deron Johnson (Member # 2475) on :
It is much easier & a whole lot mess to cut foam with a hot wire or tool instead of sanding. Here are a couple of companies that sell cutting supplies:
www.hotwirefoamfactory.com (craft-type cutting tools which do not get as hot, do not cut very fast, but have tools customizable to do shapes like shells if you like)
you can also make cutting tools yourself if you know how to work w/ electricity safely. Doorbell transformers w/ wire that demand carries can be used quite effectively.
The key is using coatings to make your product last.
Posted by Dan Sawatzky (Member # 88) on :
I have all the specialized tools of the foam carving trade... hot knives, hot wire cutting jigs etc...
But when I want to do something freehand its the old kitchen knife... serated is best.
A disk sander with a real coase grit will vaporize the stuff instantly... go easy.
We've even used an electric chainsaw to rough our bigger pieces.
-dan
Posted by Jeremy Vecoli (Member # 2278) on :
When I worked at the prop & sculpture place, a lot of stuff was carved foam. In addition to the tools mentioned above, the sculptors used "cheese grater" rasps like the auto-body guys. Blocks of foam could be glued together or built up with "box foam", a 2-part spray foam like the packaging stores use. You could also try a coating of rosco foam-coat, it brushes on and makes a hard shell. I think it is some kind of plaster with fiberglass chop mixed in.
Posted by Don Coplen (Member # 127) on :
I have a bit of experience sculting the blue extruding foam, which is a bit different, but similar. Rasps work great for roughing out a shape...the kind that look kinda like cheese graters that fit into a handle. Various grades of sandpaper, from course for major shaping to find grade for getting to the final smooth shape. Razor blades or exactos work well for cutting details.
But...what I really would like to hear here is...
what's Arvill's story bout his experiences petting mice with feathers? Maybe a good topic for a new thread? I'm from the Midwest, and had never heard of such a thing.
[ July 02, 2002, 10:12 PM: Message edited by: Don Coplen ]
Posted by J.T. Gazaway (Member # 2001) on :
Looks like I'm a little late on this one. It's been a busy week but I can add some info here. I work with EPS foam every day and could probably write a book on it but I'll try not to type one now. (Just adding to what's been covered) Hot Wires... A hot-wire cutter is probably the main tool used with EPS although there are many others I use in addition to them. One thing about hot wire cutters is that they use a very specific wire. Not just any "wire" will work. They use a nickel chromium alloy wire called ni-chrome or inconel. You can use a lot of different power sources but the best thing to use is a varible voltage transformer. (aka Vari-stat) They have a dial on them that you can adjust the amperage depending on the length of the wire. It's pretty easy to make one but would take a while to explain it. If anyone wants the details on making one, feel free to fire me an e-mail or give me a call. Grinders and sanders... There's a whole slew of things you can use for sculpting. The "cheese grater" Jeremy referred to is a bondo tool. Auto-body supply shops sell them and they come in various shapes and sizes. They are great for shaping but if you really want to rock and roll, use a dremel. I use a dremel with a flexi-shaft attachment suspended overhead so I don't have to hold the whole unit, just the business end. It's a lot like having a pencil with a spinning bit at the end of it. The main bits I use are made of titanium. They look like little spiked wheels. Another good one is a tile cutter bit. It looks like a drill bit with angled teeth. Once you have your basic shape you have to sand it smooth. The best sander for things with contour is a sanding sponge. It's about a 3x4 inch sponge covered in sanding grit. They form to the contour of your sculpture as you sand it and come in fine, medium, and coarse grits. You can also add drywall mud (or joint compound) to the surface and sand that after it dries for a really smooth surface. Coatings.... There are several different coatings that work well depending on how much abuse the piece is going to be exposed to and the type of suface you want to end up with. Most everthing mentioned so far goes on rather thick and you lose a lot of detail that way. Dryvit is an EIFS base coat that is similar to portland cement. (EIFS stands for Exterior insulation finishing system) It's pretty tough if you put it on thick enough. If your peice isn't going to take a lot of abuse, you can use elastomeric roof coating. It's not nearly as tough as the some of the other coatings, but you don't lose a lot of detail either. Now, if you want to make EPS foam darn near bullet proof, you coat it with two part polyurethane spray. This is the stuff I coat everything with. It's the same material used for sprayed in truck bed liners and is by far the toughest coating I've found. It was actually invented as a base coat for EIFS systems but is used for a lot of different things now. It's a two part spray that mixes in mid-air as it leaves the spray gun. It hardens (or "kicks") in 3 or 4 seconds. It can be sprayed on rough or smooth and it holds enamel or latex paint very well. You can even gel coat it. I have sculptures that have been outside for several years that still look just fine. (In Texas weather no less) Any company that does sprayed in truck bed liners can coat foam for you even if they aren't aware that they can. The company that sprays my work had no clue you could use it for EPS until I showed up. (They didn't know that's what it was invented for) Well, that's about all I can think of now. Hope this helps. If anyone has any other questions, just ask.
![[Smile]](smile.gif)
That's how all the houses out here are built though.. wood frame, OSB over the wall studs, styrofoam insulation stuck to the OSB, wire mesh over the foam, then stucco.