Instructables

Foam cutter from soldering Gun

Easy quick and effective. 
Things you need
1. a wire coat hanger
2. A soldering gun
3. a hammer
4. a grinder of some sort.

Cut wire coat hanger long enough to replicate  what you see in pic.
Bend the wire into the shape you see.
Now open the bend up enough so you can get at the part thats going to be cutting the foam.
Lay the wire on a hard surface, (preferably an anvil or block of steel) Pound this part of the wire flat.
Then use a grinder to remove more material from this area.
You want to make it thin enough that it heats up fast, but not so thin that it burns in half, or bends too easily.
close up your bend and attach to your soldering gun.  Cut your foam.
I used it for several cuts and it works great.  After a while the soldering gun body gets pretty warm so I would not use this for extended cutting times. but for 5 mins of cutting foam it does great.
I tried this with copper wire that worked but was too soft, then I used a bit of iron wire but it did not get hot enough... Good old coat hanger you say?! I have to try that. I used a dirt cheap 100W gun and have not had any problems with it overheating yet. The copper wire lets me cut, at least. Gotta try modding the coat hanger!
danray35e (author)  stringstretcher2 years ago
worked great for me stringstretcher
l8nite2 years ago
I did something like this except I didn't flatten the wire, it worked ok for small pieces but when I tried a bigger loop it got all bendy..thanks for sharing
Phil B2 years ago
My soldering gun similar to the one you show has two trigger positions for two different heats. Do you have any experience that would make a comparison between a lower and a higher heat setting? I am wondering if the lower heat setting would still cut the foam, but would keep the gun from becoming dangerously (for the longevity of the copper wire windings) hot.
danray35e (author)  Phil B2 years ago
I might also add that I think I could have gotten away with making the cutting part of the wire even smaller. Then it would heat better, equaling less strain on the gun.
Thank you for the responses. My gun is also a Weller made about 1967. Hot wire cutters are always a compromise between getting enough heat to cut the foam, but without burning out the power unit or causing the cutter to sag or melt. A couple of times I have improvised hot wire cutters, both with auto battery chargers putting out about 3 amps. I improvised both times with thinner steel wire I had available. Once I twisted two strands together lightly because I was afraid one strand would get soft and break. Once I wrapped extra wire around a piece of wood (without the turns touching each other) to gain enough resistance to dissipate some of the current so the wire would not get too hot. I appreciate what you have done. It is a clever solution to a problem.
danray35e (author)  Phil B2 years ago
Mine is a weller model 8200 it has two position as well. I have used it on both settings, and it seems to cut well with both. I timed how long it took to start cutting well to be about 10 seconds on high setting and about 13 seconds for low. I was cutting for prob 10 minutes on several pieces of foam before I noticed the handle becoming warm, and continued for another 5 mins. I only came up with this for the need at hand. I looked here on instructables, and everyone was talking about getting transformers etc. I needed something quick, and it worked great. If I were going to be cutting foam on a regular basis I would go with something more dedicated to the purpose. As i don't care to shell out 30 or 40 bucks every time I need to solder some wires together. But I will not hesitate to use it for the odd job of cutting foam here and there.
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