multiple pass mig welding

[deere_x475guy]

Hi gang, I need to know if its ok to do multiple pass mig welding. My manual says to do multiple pass with flux core but does not indicate that its recommended or not with Mig.

Any light you can shed on this will be appreciated.

Bob

[Mike Sherman]

Bob, it is okay to do multiple passes with GMAW - BUT, the problem lies more with the inherent problems associated with short circuit mig rather than the multiple passes. Follow this questions logical progression and the implied circumstances; If multiple passes are needed than you must be working on thicker material (in excess of 1/4" ?) If this is the case, than short circuit mig is the wrong process to use. Regardless of whether or not you are doing it in one or two passes. You need to use spray transfer mode or fluxcore wire. The potential for lack of fusion is very high on thicker material with short circuit mig, this is why you are told you cannot do multiple passes. It is not that you can't, it's the thicker metal and the process that you are using that is the problem.

[deere_x475guy]

Thanks Mike

Ok thanks Mike that clears things up for me. I can use fluxcore or fire up the ole stick machine and do anything I have to about 1/4 inch.

Bob

[Dan]

Re: Thanks Mike

Originally posted by deere_x475guy
Ok thanks Mike that clears things up for me. I can use fluxcore or fire up the ole stick machine and do anything I have to about 1/4 inch.

Bob

Bob,

Some self shielded fluxcore wires are single pass only. So make sure that your wire can be used for multipasses first before you go and use it on multipasses.