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Discussion Starter #1
Hi,
I'm curious to hear what diameter of hole punch/drill others use for plug welds. I usually use 1/4" for light metal like 20 ga. and at least 3/8" for the heavier pieces. I read on a popular site that 3/32" was what he used and it seemed kind of small to me as the top hole would be full before you got burn-in on the back sheet.
Any Opinions and favorite procedures?
 

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I think I used 5/16.. But I don't trust half the ones I did. Sometimes they seemed to not stick to the bottom metal. I could be paranoid.
 

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My autobody teacher always recommends 5/16". I've seen some recommendations
for upto 3/8" on some other forums. I think 1/4" and especially 3/32" are
not recommended.


danny
 

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Used 1/8" for my taillamp panel and it seemed to work very well. A friend who has been an ironworker/sheet metal mechanic his whole life showed me how. Was using a 110v. Miller mig welder without the gas shield and low output setting on a long, 50 ft., 10 ga extension cord to cut the voltage down even farther so you could hold the spot a little longer than expected without burn through.
 

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Discussion Starter #6
That sounds intricate! Thanks for the tips. There are a lot of "Class 1,2and 3"spotwelds called for in the manual. Having drilled quite a few out, they look like they run fron 7/16" or so down to about a 1/4" They seemed to use quite a few but when you use the manual it looks like they were called for. It's also pretty hard to find one that isn't still strong,(as long as there's still steel left) so in the pursuit of strength I'm going to make 'em big (5/16 - 3/8") and burn'em in...
 
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