hey guys, how do you cut your foam when doing your buildings and scenery? I remenber my cousin using a home made foam cutter when she was at my home, like 15 years ago, studying to be an architecth (spell) and today I'm starting to be an avid modeller, after seeing her build ups. So I've searched the net for home-made hotwire cutters but I found useless stuff so I'm trying to get your opinions about this.I'm always lookin for the cheapest deal, and there's nothin better than the do-it-yourself mode, you keep it cheap and have fun doing it Any hints about it^??

Thanx in advance and cya ya'll later

I'd say (i've seen plans online somewhere) a soldering gun with wire instead of the tip....

I use a number 11 xacto with a sawing motion

Francisco, try this site's plan to make your own:

Homemade Tools - The "Hot Wire" - Foam Cutter

That was just what my cousin had, but she used a small metal-body woodsaw as the main body of the cutter.

here is what I found:
http://www.vatsaas.org/rtv/construction/hotwirecutter.aspx

http://us.games-workshop.com/games/warhammer/painting/modeling/more_hotwire.htm but I dont understand how the body-wire and the cutting-wire connect to the rest of the piece and within eachother

http://www.techlib.com/hobby/hotwire_foam_cutter.htm

http://www.hhhh.org/~joeboy/resources/hotwire_foam_cutter/hotwire_foam_cutter.html

waiting some comments

Hi Francisco,

Basicaly, a hot wire cutter is nothing more than a "controlled" short circuit. So you need to create a support for the "cutting" wire. This cutting wire is at best special resistance wire (go to your local electronics shop and ask for it) or a simple wire (aluminium or steel, no tinned copper or plain copper) with a limiting resistor. You can use a metal body figure saw but you have to see to it that the cutting wire is isolated from the actual metal body (use plastic washers or spacers. On to some free ends of the cutting wire you can then apply some low voltage (4.5v max). Due to the high current through the wire it will heat up and this way you can cut styrofoam. The trick is to heat the wire without it actually becoming too hot so that it melts. So best is to use batteries or a current controlled power supply. Do not use accu's or rechargeable batteries as they can drain their load in one short go, causing the wire to melt and/or even kill the accu.

Hope this helps.

Kris

It really helped, thanx for the explanation!However I have some more questions...What should I use as a limiting resistor? For what I've understood the resistors will protect the body from heating, and only the wire between (resistor A) X---------X (resistor B) will be heated right?Should the electrical wires be conected directly to the heating-wire?here's a picture so we can have a starting point:




thanx again

A nice serated steak knife also does the trick

Hmm, the limiting resistor will need to be calculated depending on the type of wire, the gauge of the wire and the voltage used. So there's no ready available answer. The limiting resistor is not used to protect the handle, since the cutting wire needs to be electrically isolated from the handle (bow on the picture), on the picture you can see the insulators between the wire and handle. The limiting resistor is there to lower the current that is flowing through the wire. To much current and the wire will become too hot and melt.

By the way see if you can find a hobby and crafts store near you, these guys normally have ready made hot-wire cutters.

Kris

In the upholstery industry they use electric carving knives (the kind you cut a roast with) to cut their foams.