Plug welding problem

[elmof1]

Hi, I had a problem with plug welding a panel to my car earlier; it spattered and i was struggling to get the weld to spread to the panel with the hole drilled. Both panel are epoxy primered but I removed the paint from both panels around the plug welds.

I practiced on some mild steel the same thickness and the results we pretty good. Any ideas?

Thanks

 

[the snooper]

not clean enough or gas blown away power setting good connection to body of car ?

 

[Sean]

Stuff between the 2 sheets burning off?

 

[elmof1]

Thanks for the reply guys, the epoxy primer burning off sounds like it could be the problem. I cleaned a few mm around the weld but maybe this wasnt enough? I'm kind of commited now as its tacked in place and i've starting plugging it!

 

[PaulMcElhinney]

I have a welding tuition DVD. The tutor suggests startng the weld on the top sheet, this gives the arc a fraction of a second to reach full heat. You then drop down inside the plug and weld a circle then finish off with a slight "dwell" in the middle. I hope this helps.

 

[Sean]

Id been told before about 4 mm hole welder on max, wire speed low and give it the beanz , seems to work for nice clean well clamped joints. It just fuses the 2 sheets together. I tried it, nice flat dimple that looks like a resistance weld and decent strength. prefer the 6-8 mm hole and a circular weld more forgiving on slightly dirty, zintec or painted.

Sean