In the context of my work for the local Repair Café I was asked to weld a handle onto a cooking pot. As I knew this is generally possible, I accepted the challenge to find a way to solve this.
I have seen people doing this in the past so I new it is possible, but all these people were experienced welders, not like me welding things just for hobby. After some experimenting (and creating some hole in pots) I found a reasonable way to weld a solid handle to a thin walled pot.
Please note that in order to get reasonable result TIG welding is required! Other welding methods like MIG, MAG or stick-welding (MMA) will not work. Spot welding might work, but was not followed up due to the lack of proper equipment.
The pot was a 0.6mm steel pot with a massive handle. The handle was originally hump welded to the pot. A short investigation showed that handle was designed for a pot with a smaller diameter and was welded only with the outer sides to the pot, not with the humps as designed.
- TIG welder with programmable welding time
- round bar (copper, steel) to absorb heat
- Training objects from the local scrap dealer
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Step 1: First Try: Spotwelding
The first idea was to spot weld the handle back to the pot. As I do not have a proper spot weld equipment, I tried my stud welder pistol to achieve some results. Unfortunately this did not lead to a usable result, as most of the energy was dissipated between the copper electrode and the handle and not between the handle and the pot. As a result, the handle got somewaht molten surface the place where it touched the electrode. The handle came off the pot more or less immediately.
Step 2: Second Try: TIG Welding
I once observed a trained welder how he did TIG weld a handle to a pot. He used a timer in his welder to weld with high energy for a very small amount of time. So that was the approach I chose.
To find the correct settings, I obtained some old pots from the scrap dealer to train. The settings which worked well for me were:
Welding current : 200A
Welding time: 0.4 seconds
pre gas: 0.5 seconds
post gas: 5 seconds
The biggest problem is the thin walled pot itself. You will make nice holes in it before you know it. To prevent this from happening the are two measures to be taken:
1. dissipate the heat at the inside of the pot.
2. meld the handle, not to pot
To dissipate the heat, I put a copper bar with some copper mesh inside the pot, serving as electrode for the welding process. This can be steel as well. To prevent the thin pot from getting holes, the welding torch should primary meld the material of the handle. This molten steel should than flow to the pot and melt the wall of the pot and connect to it. If the distance between the handle and the pot is to big, you will need some filler material, e. g. by putting a steal wire between then. The pictures should give an impression how the needle was positioned.
Step 3: The Result
After making some holes in the testing objects I found usable parameters, knowing there would still be a chance to created some holes.
I fixed each handle with two spots welds. After cleaning the welding spots from the inside and the outside with acid, the results looked okay. The pot will not win a beauty contest anymore, but can serve its purpose for some additional years (hopefully…).