prayers1 153 Report post Posted April 23, 2017 I'm working on the Shock Tower reinforcements and wanted to know after I sand and prep the shock tower in the immediate area within the engine compartment, could I just cover that area with Copper Weld Thru Primer, as well as cover the back side of the braces, then weld the braces to the shock tower. Just don't have any experience with Weld Through Primer and don't know how far to go with it. I'm not using the Copper Primer as the main primer on the vehicle, just want to use it near the area of the welds. This is what I'm using, SEM Copper weld through primer 40783 Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted April 24, 2017 I used the SEM weld thru primer on the convertible inner rockers. Maybe it was me but I didn't care for it. Striking the arc and keeping a nice bead or rosset weld made me feel like a beginner welder. Quote Share this post Link to post Share on other sites
mustangmike6996 34 Report post Posted April 24, 2017 I used Sherwin Williams weldthru primer when I did my quarter. It is a bit tricky to weld but it does give you some piece of mind so you don't end up with a roached out seam a few years down the road. Quote Share this post Link to post Share on other sites
SWPruett 83 Report post Posted April 25, 2017 We abandoned weld thru primer a few years ago as they all screw with proper arc initiation and weld pool contamination. 1 RPM reacted to this Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted April 25, 2017 1 hour ago, SWPruett said: We abandoned weld thru primer a few years ago as they all screw with proper arc initiation and weld pool contamination. I like that idea. Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted April 25, 2017 13 hours ago, SWPruett said: We abandoned weld thru primer a few years ago as they all screw with proper arc initiation and weld pool contamination. so you just go with bare metal? Quote Share this post Link to post Share on other sites
Ridge Runner 1,112 Report post Posted April 25, 2017 That is what they did at the factory .The body was primed after welded together.I seam seal every joint and epoxy prime very well after i replace any sheet metal with a good Direct to metal epoxy primer Quote Share this post Link to post Share on other sites
SWPruett 83 Report post Posted April 25, 2017 1 hour ago, Mach1 Driver said: so you just go with bare metal? Yes. In the region of the weld in particular. If the panel has EDP primer applied, we leave it along the flange and buzz the weld area clean with a Roloc disc to allow all welds to be on fresh, bare metal. Then the panels are epoxy primed and seam sealed with paintable urethane seam sealer. 1 Ridge Runner reacted to this Quote Share this post Link to post Share on other sites
Machspeed 219 Report post Posted April 25, 2017 I don't know anything really, just did a bunch of research on it and in the end elected to utilize a weld through primer. I think there are a couple of Utube vids on what happens when you don't use it and some of the posts on the hot rod forums prompted me to the go ahead. I chose U-Pol and my panels welded up just fine. All that copper color you see in my photo is the U-Pol. I hate rust and will always go above and beyond to fight it. Quote Share this post Link to post Share on other sites
Ridge Runner 1,112 Report post Posted April 25, 2017 Once you have used a good direct to metal epoxy you should not have rust problems .a good epoxy is hard to even sand blast off.seam sealing all the joints will keep the rust out. 1 SWPruett reacted to this Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 26, 2017 I used the 3M weld-through primer every chance I got, and never had a problem starting a weld or performing a rosette weld. That stuff was expensive though... Quote Share this post Link to post Share on other sites
mustangstofear 608 Report post Posted April 26, 2017 We use U-Pol weld thru primer with any welding. If you weld 2 pieces of bare metal together all the Epoxy primer and seam sealer in the world won't keep it from rusting. The trick is say for plug welding is to scratch off the area your going to weld and it welds perfect. Quote Share this post Link to post Share on other sites
Ridge Runner 1,112 Report post Posted April 26, 2017 I have split panels welded together in 1935 with no rust between them ,you have a good sealed joint and no rust will get in 1 SWPruett reacted to this Quote Share this post Link to post Share on other sites
prayers1 153 Report post Posted April 27, 2017 So I used SEM Copper and had a lot of platter, so I tacked everything up then took a wire brush to expose some metal, I was able to weld in the shock tower reinforcements but not happy how the welds came out and I believe it had a lot to do with the weld through prime. I gonna apply some seam sealer. Quote Share this post Link to post Share on other sites
bigmal 225 Report post Posted April 27, 2017 I just ordered a coule of cans of U-POL primer. Looking forward to see how it works. Quote Share this post Link to post Share on other sites
SWPruett 83 Report post Posted April 27, 2017 2 hours ago, Ridge Runner said: I have split panels welded together in 1935 with no rust between them ,you have a good sealed joint and no rust will get in Yep. Same here. I've seen a fair number of '32s and '34s with pristine metal in lap joints on otherwise hammered bodies. Quote Share this post Link to post Share on other sites
