hot wire foam cutter
Moderator: Harold_V
hot wire foam cutter
I finished my hot wire foam cutter and started to play around with it...I'm going to be making a rear truck assembly for a live steam locomotive project. I'm using an LGB model train transformer, which seems to be doing a good job. I first used an "N" guage transformer, but that kept overheating and shutting off. I guess I'm playing with the cutting speeds along with and how much force it takes to push the foam through the wire. Things seem to be going along OK, but sometimes the parts aren't coming out "square" and seem as if they might be tapered. Could this be because I'm pushing too hard and flexing the wire? Also, how hot should the wire be? It shouldn't be glowing should it? (mine isn't) I'm using NiChrome wire .016 Dia. Any hints or tips???? Thanks John
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jutz
Pushing too fast will make the part sort of bowed in the middle as the middle of the wire drags behind.
The wire should not glow. I use stainless safety wire and I try to make it just hot enough that it gives when I put tension on it but not so hot that it sags under it's own weight. The ideal temperature, however, varies with the type and density of foam you're cutting so you have to experiment a bit. If you put an ammeter in the circuit, once you find the ideal temperature you can always get back to it by going back to the same current.
When you get the right temp, the cut will be just barely wider than the wire, the surface of the foam will be smooth but slightly hairy and you will be able to cut at about 4 to 6 seconds per inch with a very light load.
If the foam surface is pitted, the wire's too hot. If it takes noticeable force to push the wire through the foam, the wire's too cold.
The wire should not glow. I use stainless safety wire and I try to make it just hot enough that it gives when I put tension on it but not so hot that it sags under it's own weight. The ideal temperature, however, varies with the type and density of foam you're cutting so you have to experiment a bit. If you put an ammeter in the circuit, once you find the ideal temperature you can always get back to it by going back to the same current.
When you get the right temp, the cut will be just barely wider than the wire, the surface of the foam will be smooth but slightly hairy and you will be able to cut at about 4 to 6 seconds per inch with a very light load.
If the foam surface is pitted, the wire's too hot. If it takes noticeable force to push the wire through the foam, the wire's too cold.
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Mr Sharpe
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Mr Sharpe
I have two band saws a little 10" Delta and a 20" Powermatic wood band saw. About all that little Delta is good for is foam or real thin wood. The Powermatic of course has no trouble. I found I can almost cut the foam against the back side of the blade. You want a blade with a good number of teeth. I'm not sure of the FPM on the Delta, and I think the Powermatic is about 3000FPM. Of course, you want to have some kind of vacuum collection for that dust.