Welding Tips and Tricks

Any tips to welding unknown stainless? I was thinking 308 wire but I am not really sure. I know it's stainless but no idea what grade

Knowing what the part is used for can help sort out what kind of SS it Might be...
Welding SS without knowing what type it is can cause all sorts of problems.
If this is a critical/costly part send a bit to a lab and get a better clue of what your working with.
If its a noncritical widget and your going to have at it regardless, 309 would be a better choice.
Other choices (all potential overkill) would be 312ss, one of the inconels (625 or 82 cant remember...), or hastealloy W.

316 is also a good choice.

It's a fishing gaff for pulling 100lb fish up in the boat

Most likely to be 304.
You can use 308 filler. If you still have concerns you can also use 316 or 309.

pavetim wrote:It's a fishing gaff for pulling 100lb fish up in the boat

In a marine application (non-critical), odds are very high it's 304 or 316, and both can be welded with 308 or 316.

Put a strong rare-earth magnet to it, away from a weld. 400-series will demonstrate some or much attraction, 300- series little to none.

Steve S

It's not an already made gaff he just got hooks from hardware store, I am making the gaff. And I M in Japan so stainless unknown. It's non magnetic but a lot of SS is

If it's non magnetic but unknown I use 308.

Ahhh got it...
309,316,308 would be the choices in order. 316 first if the hooks say anything about marine use or anything along those lines.
Good chance the hooks are a 300 series, maybe 301 or 304, 303 if they have machined features, and 316 if they are "marine" hooks.
Another check you can do with a strong rare earth magnet (has to be either a neodymium or samarium/cobalt) is that if the part is unresponsive in a "flat" area but responds at a bend is more than likely a 300 SS.
All of the 300's in common use are austenitic stainless so when its bent it forms ferrite (the iron that attracts a magnet) where its been coldworked.

Do PMI(positive material identification) if you want to know which grade it is. Else using 309,309l would be a good option.