- Thread starter brendan h
- Start date
Does it just need to be smooth (as in gas flow smooth) or smooth as in a tool the same o/d as the pipe needs to get in there, or some kind of chemical, catering, etc use?
Crustiness you can pretty much eliminated by cleaning inside and outside well before welding and using purge (probably won't overly effect the strength, though -- few people who MIG exhausts in SS use purge). Or you could try pickling it. If you want a really smooth inside, a copper bar machined to size should do it.
Crustiness you can pretty much eliminated by cleaning inside and outside well before welding and using purge (probably won't overly effect the strength, though -- few people who MIG exhausts in SS use purge). Or you could try pickling it. If you want a really smooth inside, a copper bar machined to size should do it.
If it's dirty/greasy, degrease with some brake cleaner, acetone etc. It can be mechanically cleaned with scotchbrite or a stainless steel brush
Avoid using abrasives that've been previously used on carbon steel as it can cause stainless to appear to rust later
If the application is NOT particularly high stress and/or sanitary you may not need full penetration welds which makes it easier to keep the inside smooth/clean
'Purging' is needed to prevent the black crusty deposits on the back of the weld- basically covering the back with shielding gas via a second argon line. You can get away without a purge on partial pen welds if the parameters are right BUT it all depends on the application
Avoid using abrasives that've been previously used on carbon steel as it can cause stainless to appear to rust later
If the application is NOT particularly high stress and/or sanitary you may not need full penetration welds which makes it easier to keep the inside smooth/clean
'Purging' is needed to prevent the black crusty deposits on the back of the weld- basically covering the back with shielding gas via a second argon line. You can get away without a purge on partial pen welds if the parameters are right BUT it all depends on the application
