Soldering gun hot knife quick tip

by Ak Flyer | February 20, 2013 | (22) Posted in Tips

Here's a quick tip if you already own a pistol type soldering gun.  You can replace the wire tip with a small piece of wire shaped however you like to create a small hot wire knife for cutting foam.  I made a variety of shapes to try out different things and you'll find that the smaller the wire the better it works.  In fact, the largest wire shown in the picture would barely get past warm and didn't cut at all.  The best were the small sqare wire and the small sort of round wire.  They heat up very quickly and cut very fast.  Using a smaller wire to make multiple cuts will definitely work faster for hogging out a hole but a larger wire such as the large rectangular wire work well for cutting precise large shapes such as a battery box.  You can use these shapes for scooping out holes for batteries, servos, receivers etc. or they work very well for getting a straight cut making windows or cutting out slots for ailerons etc.  

Hope you enjoy this tip.  As always please comment.  Let me know why you do or don't like what I'm doing so I can make these better.  Thanks for reading.

Remember, if at first you don't succeed, sky diving is probably not for you.

 

COMMENTS

Ralphtsp on February 20, 2013
Neat tip, thanks for sharing it!
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earthsciteach on February 20, 2013
Great tip, AK. I never thought of doing this with my solder iron. I will be from now on, though!
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Jon on February 20, 2013
What type and guage of wire did you use? Where can I get some?
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Ak Flyer on February 21, 2013
I used a piece of .050" steel push rod wire I had laying around. I got it at my nearest hobby shop. You could even use a piece of coat hanger wire but it would take a lot longer to heat up and dissipate faster. The smaller the wire, the faster it heats up and the better it will carry the heat through the foam. With larger wire you can hold shape easier but it will be harder to keep hot.
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Ak Flyer on February 21, 2013
Actually it might be thicker than that, either way the thinner the better.
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RCmaniac on February 22, 2013
Cool!
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philbx1 on March 1, 2013
Hey thanks AK,
I just found your post after ordering some nichrome wire last week.
I was going to use a PC power supply combined with a Peltier power controller
I had laying around.
This is a much better solution as to what I want to do with cutting out
simple EPP battery and servo slots etc.
Excellent ideas, and thanks much for taking the time to share them!


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Ak Flyer on February 24, 2013
I really like this setup for carving out spaces when you can't penetrate through the work piece, but for through cutting where you aren't worried about depth I use a simple straight knife that I bought at a craft store for about 30 bucks. I'll put up a couple pictures of it later.
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casehatter on February 24, 2013
Well I'll be dab burn why didn't I think of that good idea I'm glad you shared that Thanks....
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mena142 on February 24, 2013
Great tip! I once tried a simple soldering iron to cut foam, but for it's nature, the tip is colder than the base, and once I but some wire in there and it would make a v shaped irregular cut. With this type of gun, the current actually flows through the entire wire and heats up equally. I'll pick up a cheap one right away!
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nergik on February 20, 2013
Sounds Brilliant! never though about it, now i can clean my soldering pistol and do a good job with it :)

Thanks
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leadpipe58 on February 21, 2013
I have one of thous lieing around collecting dust.Glad you came up with a use for it.great tip...
Just a suggestion the fumes given off from burning are not the best for you i will have a fan running if not in a well ventilated area i do the same when working with CA...
Be well
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Adib Vahedi on February 20, 2013
Thanks for the tips!

Keep up the great work!!!!!!!!!!!!!!!!!! ;)
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Ak Flyer on February 20, 2013
Thank you very much. I'm always happy to share and appreciate your kind words.
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hbxfzw on June 8, 2013
good i like it
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mark d on February 3, 2014
Something I found out by accident, If you use heavy solid copper wire it gets hotter MUCH quicker.
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Willsonman on September 15, 2016
Interesting, I tried using household electrical copper wire, 12AWG, and I did not get very good results. Perhaps my loop was too large. Something to tinker with.
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bensgreentrain on April 2, 2014
Great Idea. I have 2 of these that were going in a garage sale. Guess i'll have to keep 1 for future projects. THANKS for posting.
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Soldering gun hot knife quick tip