Greetings,

As most Ford truck owners have discovered over the years, the fenders of the bed rust out quite nicely at some point. Since mine aren't too bad yet, I figure now is the time to repair this before it gets completely out of hand. So, I ordered patch panels from broncograveyard.com, a sponsor of FTE.

They haven't arrived yet, but since I've never welded thin steel before, I bought some 20ga steel at a hardware store to play with, and see how difficult it will be, or not be. Of course, I burned right through. Turned the current and the wire speed way down, and the butt weld is atrocious and pulls right apart. Tried a variety of different settings, but couldn't get it quite right - either I burn through, or they don't stick. I'm more familiar with flux-core welding 1/8" and 1/4" plate, using a wire welder (Lincoln).

So, I started thinking about this... maybe the best answer (since I burn through often), is to make a flange on the good metal of the bed, and overlay the patch panel onto the flange, so its flush with the bed, then weld through the two pieces, then grind and skim with bondo as necessary.

Or, am I totally taking the wrong approach? Initially I thought butt-welds all the way around was the "correct" method, but I have too much burn through.

I'm sure this has been answered 100 times, but the search feature gave me nada unfortunately.

Thanks in advance!

 

This thread might help you.
https://www.ford-trucks.com/forums/s...ad.php?t=82480

I have done both types of repairs you mentioned; the butt weld is preferred where the back of the repaired area is inaccessible. It also offers a nicer finish. The flange weld is easier, but is more likely to absorb water is it is not completely sealed from the back. I had the same problems with burn through until I replaced the flux wire with solid .23 ga. wire and added the gas option to my MIG welder.

Tacking and skipping around the patch works best because your avoiding the heat build up and by running a series of tacks instead of a continuous bead, the chance of a burn through is avoided. It takes a lot of time but it's worth the trouble.

 

Yeah, well, I guess I didn't search well, that's the "read my first" thread at the top of the page But reading through, it's clear my original thinking was correct - butt welds, stitching around the perimeter of the panel to the original metal of the truck's bed.

I removed the two plastic "shields" front and back in the wheel well, to discover a large, wide piece of metal that connects the inside of the bed to the outer lip, so I'm thinking that is where the water collects in the first place. Both sides look amazingly similar in rust patterns...

when the panels arrive, I'll give this a try. Worse case I can skim it over with bondo, or I guess replace the whole bed.

 

I didn't want to crosspost as that's considered rude, however I did get the bed off, and got started on removing rust from the frame at least. Next, is the bed's wheel wells.

Pictures and documentary is here, and I'll keep posting there as not to crosspost.

https://www.ford-trucks.com/forums/s...d.php?t=372827

(in case anyone is interested)

 

I,too, have issues with welding patch panels until It was suggested I get away from the flux wire and add gas to the welder. Some of the things I found to help me:
1. Practice practice practice. Use scraps to weld together and then cut through them to examine the welds. It will give you a good visual of how the bonding is taking place.
2. Leave a small gap (.020" max) around the patch to give the weld a place to sit. If you butt them together and grind off the weld, there is no bond any more!
3. Chamfer the edges of the patch to leave more weld in the gap.
4. Always sand or grind both panels on both sides along the joint before welding. This will give you stronger cleaner welds
5. "Spot" welding refers to just welding in one spot. This is not an efective weld to bond the panels. You use spots to hold the patch in place until you have aligned it properly with the surrounding area. Once satisfyed with the fit, use short 1/8" to 1/4" welds spaced evenly around the panel to start. Let the panel cool completely before beginning the next wave. Do not use air or water to speed up this process as sever warpage could occur.
6. Once the entire panel is welded, Use a grinder to knock down the welds to about 1/16". Now use a flap disc or DA sander to smooth the joints. The grind almost always leaves digs or gouges bit the sanding will leave a prepped surface that required little or no filler to smooth out.

 

Yep!

Like so, more or less (probably less!)

https://www.ford-trucks.com/forums/s...d.php?t=374526