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| bkrantz |
Dec 17 2019, 09:45 PM
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#1
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914 Guru ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 8,616 Joined: 3-August 19 From: SW Colorado Member No.: 23,343 Region Association: Rocky Mountains
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So based on experience and expert knowledge, what's the best way to prep metal for lap joints, especially with plug welds? No paint or treatment? Ospho? Weld-through primer? And what about seam sealant after welding before paint?
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| Literati914 |
Dec 17 2019, 11:42 PM
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#2
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Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 2,211 Joined: 16-November 06 From: Dallas, TX Member No.: 7,222 Region Association: Southwest Region |
Scuff to clean metal, then phosphoric acid, let dry...then clean w/ wax grease remover, then epoxy prime, let dry...plug weld, scuff away slag, grind if needed, then epoxy prime the exterior of the new seam, add seam sealer... then the top of the sealer will get epoxy primed again before paint, of course.
There's more than one way to skin a cat but I've read at least a couple of articles that compared weld thru primer with just using epoxy primer.. and the EP was the victor. So, anyway that's the technique I favor, one less item to buy, if nothing else (I've paid good money for Weld Thru primer that wouldn't spray too), YMMV. |
| BeatNavy |
Dec 18 2019, 04:06 PM
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#3
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Certified Professional Scapegoat ![]() ![]() ![]() ![]() Group: Members Posts: 2,960 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region
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(I've paid good money for Weld Thru primer that wouldn't spray too), YMMV. Ja, me too. I've had several cans go bad on me that have barely been used (IMG:style_emoticons/default/dry.gif) At least I know I'm not the only one. |
bkrantz Consensus on Lap Joint Weld Prep? Dec 17 2019, 09:45 PM
cary Metal : ?
Old on old ?
New on Old ?
New on new ?
... Dec 17 2019, 11:22 PM
bbrock
Scuff to clean metal, then phosphoric acid, let d... Dec 18 2019, 09:00 AM

FL 000
This was my process too. Only thing I'll ad... Dec 18 2019, 01:43 PM
Costa05 Definitely no expert here but I lap welded my fron... Dec 17 2019, 11:54 PM
Tdskip UPol high zinc does not burn back much it at all i... Dec 18 2019, 11:18 AM
cary I use the same U-Pol weld thru primer.
But it only... Dec 18 2019, 02:09 PM
FourBlades Weld through primer is a misnomer in my opinion. M... Dec 18 2019, 02:49 PM
Superhawk996 Just a generalized statement.
Avoid lap welds i... Dec 18 2019, 03:58 PM
bretth Weld through primers I have used always contaminat... Dec 18 2019, 04:18 PM
doug_b_928 I've been following a similar procedure to mos... Dec 18 2019, 04:21 PM
rjames FCA Explains Ban on Weld-Through Primer Dec 18 2019, 08:27 PM
doug_b_928 Here's a link to a discussion I had a couple o... Dec 18 2019, 09:38 PM
bkrantz Thanks, everyone. Dec 18 2019, 11:06 PM
mb911 The ban link is a good one.. Remember steel melts ... Dec 19 2019, 05:52 AM![]() ![]() |
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