spatter and porosity?

[Trevor]

Have been using a mig the past few days with good results. Today though lots of spatter and weld hollow/porous. I was burning through metal at low amps, completely different results from before. I also tried using arc, also with poor results, puddle dirty, lots of bubbles and burning through metal. Wondered if the metal may be a little bit damp. Any suggestions appreciated.

 

[justin]

dirty metal ? forget to turn the shielding gas on? i did that this morning

 

[Trevor]

Thanks Justin, shielding gas turned on, metal had protective coating as purchased but not dirty?

 

[nickk]

there must be a contaminant on the surface,try abrading the weld area with the grinder.

 

[keith19]

As above.
If arc gave similar results it's got to be the metal. Does it differ from metal you've used previously, when the welding went okay?

Cold damp metal is not so good as warm dry metal, but it shouldn't make that much difference, especially with arc. There must be a surface coating of some kind? Try a flap disk on one area, wipe with a clean rag, then test with the mig.

As an afterthought, clean up the area where the earth clamp is situated as well.

 

[the snooper]

sounds like a gas problem to me are you using the disposable bottles or a larger one, if the disposable you only get around 10 minutes weld time from one