Hot Knife Sculpture

[Super Squirrel]

I have a ton of styrofoam and I have an exacto knife and I have candles. But I'm having a hard time cutting styrofoam in order to make game props. Anyone willing to give me some helpful advice on what I might be doing wrong?

First, I seem to be collecting gunk on the exacto knife. Second, it lets me cut through maybe an inch of styrofoam at a time. I swear I'm doing something obviously wrong and would love to know what.

[Captain Obvious]

Go to a craft store and buy a foam cutter. It's basically a wire that's heated by a couple of D batteries. Works awesome.

I saw one at a Games Workshop store recently too. I would imagine any place that sells a lot of model train stuff would have them as well.

[Madstone]

Styrofoam is a harsh mistress. A hotwire is your best bet, and fairly easy to build. Using a knife, even a hot one, is a messy procedure at best. I've had limited success with an electric knife--you know, the one that only comes out for Thanksgiving? Still messy (lotsa particles) but much faster. The key then becomes to use a lighter to slightly melt the sides and edges into a more solid mass.

WARNING: :coach: Always burn or melt styrofoam and plastic outside! The fumes can and will be dangerous!

A great method for creating faux stone is to brush an area on the styro with water, lots of plain water, then apply the lighter and watch it melt away the dry areas. Another trick to solidify the final product is to paint it with glue, or wrap it in cloth soaked in a glue solution. This one is much easier to pain, too. I've done a lot of props with styrofoam, and every time it's a new experience. A very harsh mistress. I hpe that helps, good luck! :thumbup:

So, what are you making, anyway? Be sure to post pics after :yes: :)

[Super Squirrel]

How much does a hotwire go for?

[Captain Obvious]

Eight to ten dollars as I recall. If Madstone has a set of plans for you to work from, you might be able to build it for cheaper. It is a pretty simple tool, overall.

[Madstone]

How much does a hotwire go for?

I've seen small ones at Michael's (local crafts store) for under ten dollars. I hear Wal-Mart might even have them. If those fail, you can build one yourself (http://www.terragenesis.co.uk/reference/makeahwc.html).

[Super Squirrel]

Under 10 dollars is good. This raises the question though... do I buy one now or do I instead buy a surge protector which I also could use. Hmmm.

[Evil Steve]

Super Squirrel, I've done a fair bit o' foam work so take heed....

1-If your going to work with foam, get the wire cutter. Nothing else works even close to well. Most other things work badly.

2-When you get the wire cutter, get an adaptor from somewhere like Radio Shack and splice the wires onto the cutter. Its either this or spend half of your rent money on batteries for each project. Wire cutters are hungry beasts.

3-Use high density insulating foam. The stuff you get with your stereo gets gooey when heated, thus gumming up your wire and creating alot of burning plastic death.

4-Whist you are at the craft shop, go to the florist section and get a spool of uncoated wire. Its cheap and easy to tie to the cutter.

5-White glue or carpenter's glue are now your friend. Super and plastic glue will melt syrofoam. For burn scars and melted bits, this is good. For assembly this is bad.

6-You need to seal your foam with glue before you spray paint it. The stuff that makes spray paint actually spray will disolve the foam. I've seen it used to make riverbeds and the like, so the disolving can be useful. When I seal foam I mix 1 part water with 4 parts white glue and a drop of green food coloring. Paint it on with an old brush and wait for it to dry. The green parts have been sealed. Anything else is not and needs to be painted again. Sealing the foam also makes it just a hair more resiliant.

7-Remember:the hot wire on the cutter will not cut through cardboard. I know this sounds condisending (sp?) but follow this through to its logical conclusion....templates! If you're going to be building a cityscape or just a bunch of small vaguely similar buildings, you can mass produce the various faces of the buildings with you templates. Pin the carboard to the foam and cut away!

8-The most important piece of advice I can give (and have given several hundred times during lessons) is this:All Terrain Looks Like Crap Until it is Finished.

There's my piece on styrofoam construction. I love building terrain. Please keep us updated on your projects, please.