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Hot Wire Foam Cutter

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Bernd:
If any of you have read my Air Boat thread you saw that I have a nitro powered speed boat. Great fun until the engine dies way out in the water. I plan to remedy that by building a twin electric motored rescue boat. It will have two pontoons on it made from sytrofoam that will be covered with a layer of fiberglass. But in order to shape the styrofoam so that you get nice edges one needs a hotwire styrofoam cutter and that's what I built.

The whole write up is on my web site at http://www.kingstonemodeleng.com/MachineShop/foamcutter/foamcutter.htm. I'll touch on the high lights here. If your interested in building one the details are on web site.

The table is made from a piece of tread mill. The wood is MDF and coated with some kind of plastic. Nice for the foam to slide on.



I built up an overhead arm out of wood and attached 1" aluminum angle plates.



The wire is .015" thick nichrome wire about 20 to 24 inches long. It is attached with home made fastners.



The power supply is out of a computer. I'm using the 12 volt supply. Here's it what it looks like cutting the foam.



And the cut pieces. Nice and smooth.



Later I found a 15 volt DC power supply and tried that. Works even better. Here's the temporary set up.



I use the aligator clip on the wire to adjust how hot the wire gets by moving the clip up and down on the wire. This set up will work for the rescue boat project. Later I plan to make this a bit more permanent.

Regards,
Bernd

andyf:
Berndt, how do you stop the molten edges of the foam welding itself back togeher again once the hot wire has passed through? When I tried it, using wire stripped out of an old hairdrier, it sealed up again behind the cut :(

Andy

dsquire:
Bernd

Great project. This is something that a lot of modellers could have a use for. Both boats and airplanes. I know that some of the guys that fly on floats can't come out unless someone comes with a boat for retrival purposes. :ddb: :ddb:

Cheers  :beer:

Don

Bernd:
Andy,

It never glues itself back together again. Could be your wire might be to hot. It should just be hot enough to cut through the foam. I'm sure different types of foam will probably melt at differrent temps. The blue foam that I'm using doesn't seem to melt back together. I tried some white foam such as used for boxes and there was some melting back together.

Guess I'll need to experiment and see what the different colors of foam do.

Bernd

Bernd:
Don,

I've seen many types of foam cutters on web sites but never any explination as to how they were assembeled or what they used and how. I also know that each situtation is different.

I first came into contact with very large cutters from the guys that built there own hovercrafts. I've got plans to build a 2 person craft. Another project I'll probably never get to.

I realize that each project is unique and will need it's own foam cutter design.

Any way now I can get on and start with the 2 pontoons. I'll be starting a thread on building the rescue boat next.

Bernd

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