I know that patch panel welding has probably been discussed numerous times here. However, I have a 15 minute time limit with my searches! "Weld patch panel" comes up with a plethora of non-related issues. Frankly, I got tired of looking through the posts for my answer.
I finally broke down and ordered the lower rear quarter patch panels for my 67 Suburban. They have not come in yet, but I am trying to decide on how to install them.
Should I overlap the panels (with the new panel inside the existing panel)? My thoughts are to sheet metal screw them together, then weld and grind the seams, then smooth with bondo.
Should I try to get my cuts aligned and butt weld them?
Thanks for the assistance.
Another quality post. Real Trucks Rattle HELP! The Paranoids are after me!
Hey Rusty, I’m a complete noob at welding but in what I’ve done so far I prefer by far is to have a tight joint and butt weld. It takes a lot more time to slowly sand away material to ensure your butt joint is tight but to me it’s much easier to weld than a lap joint and there is no gap for moisture to get in. I’m sure there’s people on here with far more experience than me that will guide you better, good luck!
Rusty Refine your search to posts by user MPandC (Robert). He won't lead you astray. I would agree with Dongray about using a butt weld. On a quarter panel that welds to a door pillar, it makes it relatively easy to line up and scribe the patch panel for cutting. Then trim it a tiny bit large and cut down to fit closely. As long as you can get a dolly behind the joint area, that's the way to go. Robert has posted an example of a "ghost line" that's visible in a finished panel that had a lap joint patch. I'm definitely a disciple of Robert's procedures (although I'm nowhere as talented as he is.) I've tried to take pictures of fitting and welding patches. You're welcome to scan through the photos linked in my signature to see what I've done.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
…...and to show the effects of a ghost line that Kevin spoke of, this video shows a ghost line in the rear tailgate of a wagon that had been repaired using a step flange to attach the patch panel at the bottom.
This occurs because you have two thicknesses of metal to one side of the weld seam, and one to the other side. A single thickness will expand and contract more quickly than two thicknesses. Given enough heating/cooling cycles, this differing expansion/contraction rates will cause a ghost line to appear in your paint finish showing EXACTLY where the repair was made. Using butt welds will help to eliminate this .. Planishing, grinding welds flush, as discussed in the sticky thread help to eliminate it further.
