Welding pot metal is not as hard as people say, but it is not as easy as you might think…unless you know the tricks.
Pot metal is used for all kinds of cheap trinkets like figurines, cookie cutters, hole punch handles and especially old automotive window crank handles. The problem with welding this kind of stuff is that sometimes the effort that goes into welding it is just not worth it. But there are some things made from pot metal that are worth fixing. Some of the ones that come to mind are antiques, old classic car parts like trim and ornaments, and grandmas old cookie cutter that is not worth anything but has sentimental value.
Pot metal is made from aluminum, zinc, copper and possibly a few other low melting point metals in various combinations. It’s also referred to as Die Cast metal.
It’s the zinc that makes it a pain to weld because zinc has such a low melting point and also tries to out-gas when tig welded. But It can be welded with few problems if you know how.
The 3 main welding rods are :
- Alladin 3 in 1
These rods are advertised to be able to weld using only a small hand held propane torch. That is actually brazing, not welding, but the sales guys at boat shows are really impressive when they braze repair big holes in beer cans.
But these Zinc aluminum brazing rods can also be used to Tig Weld Pot Metal.
If you are pretty decent at tig welding aluminum, you can surely read this article and do OK tig welding this stuff too.
Generally, pot metal parts are pretty clean so only a minor bit of grinding is required before welding. Usually the problem is that something just broken off clean. If that’s the case, a little grooving out of the crack will permit enough penetration for a strong joint. Remember, if it’s an ornamental piece, and its broken because someone dropped it, Its going to break again if its dropped again no matter how deep you penetrate the weld, so take it easy on the penetration.
You need an A/C tig welding machine with high frequency start. Most jobs can be welded with a small 1/16 inch tungsten electrode with a blunt taper on the tip. Set the amperage to only about 80 amps and you probably wont even need near that much.
Tig weld it just like you would aluminum except that you will only weld for about 5 or 10 seconds at a time before stopping to let it cool. Just when it gets to flowing good. STOP! Its about to melt and fall in your lap. That is the best tip around for welding this stuff.
Stop often and let cool.