Mini solder torch
Summary
This is a small soldering iron that fits in a pocket. In this page there is information about how it was made and how well it works.
How it is made
This mini soldering iron is nothing more than a soldering tip designed for torches attached to a small barbecue lighter.
The tip is originally made for larger torch units but this mini butane lighter has enough power to drive it for a quick fix. The flame of the lighter passes through the heat sink, transferring its heat to it. Plain wire was used to attach the tip to the mini torch.
The wire is woven around the tip in such a way that allows it to be attached or detached easily.
Performance
There is no automated temperature regulation. The only means of regulating the temperature on the tip of the iron are:
- The valve on the lighter that makes the flame smaller or bigger
- Putting out the flame and re-lighting it
It is not easy to overheat the tip though - the wattage on the tip seems to be low. After all this tip is designed for larger torches.
Power test
The net heat transferred to the tip is measured by monitoring the tip's temperature. A K-type thermocouple is attached to the tip with some thermal grease. The thermal grease is rated for 300°C.
The torch is lit on a medium flame and the time interval for ascending 100°C is measured.
It takes 25.5 seconds for the temperature to rise from 29°C to 129°C. The soldering tip is quite small made of steel and weights 1.8 grams. Its heat capacity can be estimated by multiplying by the material's heat capacity. Steel has a heat capacity of about 450 Joules per Kg per °C, so the tip has a heat capacity of 450 * 0.0018 = 0.81 Joules per °C. When its temperature ascends 100°C in 25.5 seconds, it absorbed 81 Joules. Therefore, the wattage of the heat transfer on the tip is 81 Joules / 25.5 seconds = 3.18 Watts.
This power is very low for a soldering iron but it is still able to reach a proper soldering temperature and help make a few fixes.