Help with plug welding

[sevenTseven]

Virtually all of the plug welds I do seem to end up with this circle around them after grinding. Looks like it isn't completely melted to the surrounding metal, any idea what causes this? Is it even a problem?

 

[englewoodcowboy]

Looks to me as your heat/feed is not set right. Looks like you are melting the holes larger and only getting pool melting on the substrate. I would make sure your heat is set according to the thickness you are welding and slow your feed down some. You have to fine tune your welder to your speed. Also try figure eighting your weld rather than circle welding. It is too hard to say what it is exactly without being there but it is somethng you will have to experiment with until you get it. There should be no line when you have a proper bond.

 

[sevenTseven]

I use the settings on the welder door as a guideline, but it seems to matter what adjustments I make I still end up with that, or I get no "sizzle sound" making me think there is not enough heat to have a good arc.

BTW, its a Hobart 140, using a 75/25 gas mix at around 20psi.

EDIT:
Using .030 wire, maybe I should drop back to .023

 

[deltarat]

The .023 will be better for the sheet metal.

 

[TN1776]

Like the others, I believe you're running a little too hot - the ring looks kind of like an undercut weld. For sheet metal I'd definitely drop back to .023 wire too. Play on some scrap and see where that gets you.

 

[plumbdoctor]

um oh um.... sorry, looking at your avatar! I have the Hobart 140 as well, the -23 wire works well for me

 

[pcf_mark]

It looks like you are welding the "plug" in the middle of the hole. You have a dab of weld bonded to the inner panel basically sticking through the outer panel. If you strike your arc at the edge of the outer panel and carry into the lower panel you connect the two with weld. I use an O or circle pattern to stitch the two bits together when molten. Keep going around the edge of the hole until it is seemlessly welded. Then you can go back with another pass to fill the center if it is low. You may be trying to fill the hole first and not melting it into the outer panel well enough.

Also if the panels have a gap that is going to make for more difficulty welding it clean.