DIY Cold Heat soldering iron

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Step 4: Parts List

What we are going to construct is still technically a resistance style soldering iron like a traditional iron, but instead of heating a metal tip to melt the solder and heat the joint, we will be heating the work directly. We need just a few simple parts. Many builders will have most of the parts already.

We need:

1. A power supply with low voltage and high amperage. Anything around 5-10v and 5+ amps should be sufficient. After scrounging, it occured to me: an old PC power supply! it has a 5v circuit rated for around 15 amps.

2. An old soldering iron or anything suitable for a handle.

3. Two small scraps of copper or brass. Any metal may do, but it's what I had.

4. A sliver of mica. You don't have mica? What the hell... ok.. Just use some plexi-glass, like I did. People have also recommended Glass or a slice of a ceramic light bulb socket. The thinner the material, the better. Somewhere around 1/8 to 1/16th of an inch would be good.

5. A few feet of 8 to 12 gauge wire.

6. A working solder gun (Yes, I understand the irony...)

7. some lead refills for a mechanical pencil (thickness doesn't matter)

8. Some tools, including a small file and a wire snips. The actual list of tools may vary slightly depending on the parts you scavenge and what kinds of destruction you must rein down upon them to get them to cooperate.

9. Electrical tape.

10. A Craftsman multimeter. Optional, but highly recommended. There is no better precision instrument available.

11. A variable resistor of some kind that can handle the 5V voltage coming out of the PSU. I was thinking a pedal from a sewing machine, or perhaps a standard rheostat of some kind. This is also optional and the demo here is made without one, but many people have made this recommendation.

Now pile all that together and go have a snack.. When you return, we begin the chaos.
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GamerM2 years ago

First YOu will need soldering gun.
luky833 years ago
i'm going to try a piece of an old pcb for the dielectric, easy to shape, heat resistant, not sure it's a proper dielectric though
tamurlane63 years ago
just some tips if you are trying this...

1. Pencil lead from a standard No 2 wood pencil fits very nicely into female molex connector pins. Makes tip replacement a snap!

2. after taking apart a wood burner/soldering iron, I noticed that they had wrapped the copper coil around a thin tube of mica. you can use this for the insulation between your contacts.
BFeely4 years ago
How about instead of a rheostat, a PWM circuit with a MOSFET. I'm (ab)using the circuit found at for my resistance solderer.
Rotflol. For the win.
irishjim685 years ago
I disagree with the Craftsman, My experience holds a Fluke DMM such as those found here in that spot.
photozz (author)  irishjim685 years ago
quiet.. I'm trying to win the Craftsman contest. Your blowing my cover. (Yeah, Fluke rocks as well)
jeff-o5 years ago
As an alternative to thin pencil lead refills, I suggest picking up 2mm thick drafting pencil leads, like these. I think that you would see far less breakage and better heat resistance than standard 0.5 or 0.7mm leads.

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