Hot wire foam cutter

Something I threw together with spare parts laying around. If there’s interest I’ll go into detail.
Hot wire gun case foam cutter. Gonna cut some foam later this evening.

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Ok, I’m done for the night.
This was a use what you have build. I did need to buy a dimmer switch, Less than $9.
power supply is some sort of computer power supply. Pulled it from a dumpster on a job site years ago, probably a decade ago. Everything else is just garage stuff.

I got lucky with my “cutting wire”. A lot of the diy hot wire cutter tutorials say to use guitar string. My son is a professional guitar player. There is plenty of used strings around. I could not get one to last more than a few minutes. I tried a ton of them. Turns out I had this spool of unknown wire. Thought it was steel but turns out it’s not. No labels on the spool. It’s not magnetic. It works great for a hot cutter wire. Glad I tried it, got lucky.

The dimmer switch controls the voltage. Thought I’d be able to use it on the output side of the power supply. 12 volt dc. I couldn’t get it to work so I just wired the dimmer into the AC input side of the power supply. I’m sure its bad for the power supply but I don’t care. It does’t work too low but can get down to about 6.5 volts in the working circuit. 7.25 volts was about the best. Too hot and you burn your foam. Too little and it doesn’t cut well.

Wire was just glowing slightly while cutting.

I didn’t want to build a whole assembly. Who needs more stuff laying around. I was able to turn a woodworking table into a temporary hot wire cutter. Already had the hole in the table for a clamp, vice was there. Used a bar clamp as a tensioning device. I’ll keep it set up for a few days. Got some other cases to cut after I finish this.

I’m just rambling nonsense now...

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Nice job! At first I thought you were a tradesman, specializing in exterior commercial wall finishes and insulation, cause that’s how a lot of built up ectrrior walls are formed once the exterior metal studs go on. I figured you worked in that craft, using the hot wire to cut and form the styrofoam panels.
They used a set up much like yours, but larger in scale.
The second Sacramento Kings ARCO ARENA stadium I was fortunate to work on was built that way. Although the exterior walls looked like solid concrete one could easily shoot an arrow thru it
 
The dam was originally built in the revolutionary war era. Had a grist mill on each end. Someone burned the mills, British, indians, who knows. It was thouht George Washington stood on that dam at one point.

The thinking was that it was a wooden and cobble dam that got capped with concrete at some point. All those people on the dam while I’m hamering, they are historians, geologists, archeologists, DEP, Nrcs — all expecting George washingtons bones to pop out.

Nothing, the entire dam was concrete. Wooden timbers in the water but nothing in the dam itself. I pulled a large cast iron pipe out of the dam, it had a foundry mark of 1921. Sometime after 1921 that dam was rebuilt. Who knows why.

In the 50’s there where a couple of bad hurricanes back to back. The river decided to go around the dam creating that island. The powers that be finally decided to remove the dam, thats what we did. Widened the channel by removing half the island and built that false bank, removed the dam and sent the river back on its intended course.