Zzeal Posted September 8, 2009 Share Posted September 8, 2009 I'm getting ready to weld on some Hard Dog frame rail caps. I really wanted to coat the back sides of the caps with something, but didn't know if anything could survive the intense heat. I did a "weldable primer" search but didn't find any conclusive info there, so we did a test. We coated two scrap 12 ga. pieces with 3M's weldable primer, mig'ed them together and found the primer wasn't affected by the heat! Now that's what I call $32 a can, paying off!. You can see where I scratched off the primer after it cooled. We also had a chance to sample Eastwoods version of the primer and much preferred 3M's. Steve Quote Link to comment Share on other sites More sharing options...
DeleriousZ Posted September 8, 2009 Share Posted September 8, 2009 Great info! Just make sure to wear the proper protective breathing gear when welding over primer/paints. Those fumes are bad news bears no matter how you look at it! Quote Link to comment Share on other sites More sharing options...
junglist Posted September 8, 2009 Share Posted September 8, 2009 I've used the U-POL weldable primer with good results, I think it was like $24 a can. Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted September 8, 2009 Share Posted September 8, 2009 Any idea how/if it effects the weld? Quote Link to comment Share on other sites More sharing options...
Namor Posted September 8, 2009 Share Posted September 8, 2009 I'm about to do the same bad dog frame rail install and have been wondering what I was going to do about this situation. Problem solved, but did you happen to get it locally? With the large amount of things I've order off the net recently, I've really started to prefer getting things locally, even if it means a few more dollars. Quote Link to comment Share on other sites More sharing options...
Zzeal Posted September 9, 2009 Author Share Posted September 9, 2009 I went to 3M's web site and got the low down on their Weld-Thru Coating II, #05917. It's "designed to prevent corrosion from forming between two weldable metal surfaces". After welding, grind the welds, and if you're going to use plastic filler they advise you to remove the remaining weld-thru. If you're just painting after grinding, they'd have you spray 3-4 coats of weld-thru to the weld area's and follow with primer (especially theirs) and paint. ------------------------------------ Flexicoker- It's introducing an impurity to the weld, but it wasn't enough for us to notice, it welded just fine. ------------------------------------ Namor- I found mine at a welding shop, four others didn't carry it. Steve Quote Link to comment Share on other sites More sharing options...
just4kinks Posted September 9, 2009 Share Posted September 9, 2009 I recently tried the SEM Brushable Weld-Thru Primer, and I didn't like it. I found it very hard to strike an arc, and there was too much spatter. In the end I gave up on it and used a butt joint instead. If you want it locally, try an auto body paint shop. Quote Link to comment Share on other sites More sharing options...
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