Hi All. I'm new to auto body welding and I had a question. When you weld in the patch panels on the lower bed of your truck, either before or after the rear wheel, do you butt weld those on, do you flange the patch and do a lap weld, do you plug weld a strip onto the back of the panel and then butt weld the patch on top of that or what??? Same question for welding in floor patches, etc.

Thanks everybody.

I always butt weld. Takes more time but it's worth it.

Thanks for the reply Scottri. So, if you're butt welding say the rear lower portion of the bed, behind the wheel well, do you weld a piece behind the panel from the back side that hangs down past the cut to put the patch against and then butt weld the seam? Or, do you just butt weld it on with no backing?? I saw on Autobodystore.com where they were replacing a door bottom. They cut off the bottom, then plug welded a metal strip that hung down past the cut off portion. Then they fit the patch against that strip and butt welded the seam between the door and the patch.

I don't use any backing. I use clamps and large magnets to hold the patch in place and tack weld a few spots. Check that everything is how and where I want it then fill in a very small area at a time, let it cool, move to another area of the patch and so on.


Scott

All of them are done by professional body shops even gluing patch panels into place. It is just a matter of what you feel comfortable doing. If you are restoring a truck to original condition and attempting to achieve a "100 point" restoration the only method would be butt welding and grinding both sides. If you are a novice and just want a nice daily driver, a flanged panel is much more forgiving for welding (lap joints). Tabs help hold the panel in place for fitting or welding but magnets can do the same thing. Most important...have fun, 90% of a good repair is in the preparation!

Just my 0.02!

How do you guys get around the problem of the magnets pulling your welding wire out of your gun too fast (with mig welding)? I can't seem to weld anywhere near magnets that are holding panels in place.

If I'm not mistaken, board member Gee Emm has a pic of what you're asking about on his blazer redo thread. Do a search and take a look. He is butt welding the panels together using a small devise to hold the panels flush. Thats the best way to do it if you can. If you don't think you want to attempt a butt joint, then maybe make a very narrow backing for a flange. Tack the backing to the original panel then fit and lay the replacement part in place. A small gap (about an 1/8th inch or smaller) will be what you'll need all the way around the patch. Use a straight edge as a guide as you work to keep the panels flush, this is important if you want a good repair. Tack the pieces together alternating sides til the tacks are about 1/2 inch or so apart. carefully grind the tops of the tacks till smooth, then fill with a filler. Keep in mind you'll need to seal the back side of the repaired area to protect against future rust (there will be a small lapped area where the backing was used)

if you try to flange a bed patch panel you will only make more work for yourself. you can use copper behind where you are welding to help with the heat. i have a piece with handle thati got from eastwood that works great for filling little holes with minimal heat. if you put a strip behind it thats jsut more stuff that you have to coat to prevent rust.

Thanks everybody. I really appreciate the advice.

These clamps are the way to go. I see lap welding as a potential rust area so I do all butt welding. You must have a gap between the two pieces and it takes a while to learn the proper settings to tune your welder to for good results.

Here is a pic of the clamps, apparently you can get them at Harbour Freight.