Homemade COLDHEAT.

Source: http://www.josepino.com/?how_coldheat_homemade   Tags: howto circuits diy homemade

Basically, the "COLDHEAT" soldering tool is just a simple circuit with a resistor (carbon rods), a switch and batteries.

I purchased the parts needed for it, except the carbon rods. I decided to get it from a pencil.

I found a power connector that holds the carbon rods perfectly, so I used it as the tip connector.

First, I disassembled a pencil to remove the carbon inside (graphite). I was extremately careful when I did this.

The tip and switch connected directly to the battery holder and the home-made coldheat is done. I used a lot of solder to ensure the connection. The only problem is: The heat melts the battery holder easily, so I had to be careful.

Finally I add a LED and 1k resistor to monitor when the circuit is on.

After it was completed, I did a test. Unfortunately, it didn't work properly. The heat generated is not enough to melt the solder. I changed the carbon with another one with less resistance, I made it shorter and still not hot enough.

The picture shows the last version, it melts the solder with fresh batteries (new) but it takes a while. This is not enough to say "It works". What exactly happen and why it doesn't work?

First, the coldheat soldering tool, basically generates heat because the current finds resistance at the thin point of the circuit, so the problem with my homemade "coldheat" is the tip is not wide or thick enough. The resistance on the tip is high and the heat doesn't concentrate on the tip.

I used 9 volts and it works, however, the entire tip gets hot. To fix this problem, I need carbon rods like the ones that are used on carbon-zinc batteries.

As soon I get the proper carbon rod, I will try it again.

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