I use the 2nd lowest setting on my welder for sheetmetal. The lowest does not penetrate very good and any higher and you can blow holes. Test weld a couple of pieces together and view it from both sides, you wil see what I mean.
I also like to leave a small gap around my panels. This allows the weld to grip both pieces. A tight fitting butt joint may expand or contract and contort the surface and require even more dolly work.
This reminds me, you may want to hammer between rounds of spot welding. The finished result will be a smoother panel that requires little or no filler.

 

Yes, I did some practicing on sheetmetal yesterday. I'll admit it was all old cab corner material (up in the good section of the cut off material) and that I didn't clean the material prior to experimenting.

I am using some butt welding clamps that I found at Harbor Freight. They hold the material in a forced gap of .040.

The lowest heat setting did not penetrate as you mentioned, the highest blew holes.. one of the other two worked sometimes..

Thanks,

Sam

 

As I said I am no pro, but my understanding is that the wire speed and how much stick out is more of a factor on the amps then the 1,2.3.4 settings. the closer you get the more amps are put to the metal and the faster the wire feed the more amps avialable. try to cut back on the wire feed speed. I have the but weld spacers you mention maybe $4 a pack compared to Eastwood 2-4$ ea. What size wire are you using the smaller .023 is better for sheetmetal. Hammering after first setting up the panel and tacking is a good Idea because the big disadvantage to mig is the wire is too hard to hammerweld flat as apposed to gas and tig when the project is done. Grinding is in store to level the weld area leaving room for more warping. Esab has a wire that is called EZ Grind that is designed for this but welding and patch panel repair being EZier to grind after welding. Ed ke6bnl

 

I am using .023, having read your article, outstanding by the way.

My welder has the four power settings, 25/35/50 and 75 amps.

More experimentation to go!.. I have a while til I need the good sheetmetal skill. Will do the cab floor first, have already done all the heavy welding with flux.

Sam

 

If I can make a suggestion on grinding the welds:
Use a grinder if you must, but only to take down the welds just above the surface. I have found that finishing up the grinds with one of the Dewalt (only brand I have found) flap sanding discs works best at keeping the weld area from getting gouged. I use the 220 grit for this because it sands welds quick but if used gingerly, the weld area is left flat (providing the panels are on the same plane).

 

Krosati...I have been restoring my 53 F-100 for the past two months. The time finally came for me to deal with the rusted out edge of my roof panel. I've never worked with sheet metal before I began this restore. Your post on patch panels gave me the confidence to proceed with doing all the body repairs myself. The results off my work based on your instruction can be veiwed in my gallery. Thanks. Jvmcc

 

Great job, I can't wait to see the final result.
$40 an hour times 10 hrs adds up. I'd rather spend that money on thee truck rather than the bodyshop!
Keep us updated on the progress.

 

If you coat an area where you are going to weld with Por-15, you need a supplied air respirator. Under the heat of welding, Por-15 breaks down into, among other noxious gases, Oxides of Nitrogen, and Oxides of Sulphur,both of which have a 2PPM level of which is IDLH-( immediately dangerous to life and health). I was wearing a respirator with charcoal filters, but the gases came right thru. I couldn't smell or taste them ,but I got enough of a dose to wind up in the ER. It felt like a 500Lb weight was on my chest. The hospital said that since I wasn't already dead, I probably wouldn't go toes up, but there was no way to tell if lasting harm had been done. Por-15 is a good product, and I was smart enuf to use a respirator when applying it, but the welding thing was unforseen. I buy all my autobody stuff at Finishmaster, and it all comes with MSDS's ( material safety data sheets). And this is for use by professionals. Por-15 is sold for use by amateurs, and,in my opinion you are not adequately warned.

 

Hey I was just wandering how you held the patch panels in to spot weld? I am getting ready to do the corners on my 55, but I am not sure how to hold them in place once I get them cut to fit. Thanks

 

I am going to use a set of clamps I got from Harbor Freight. They have a small band that slides between the two pieces and clamps from both sides

called Butt welding clamps

here is the HF item

Butt Clamps

Sam

 

Sam,
those clamps are great, Thanks for postin the link. I've been lookin for them even in H.F. I couldn't find them . Ididn't know what they called em. Now I can get them!!!
Thanks
Mike

 

seems like HF get about 5$ a set while Eastwood get about 25$ a set for what seems like the same thing. Ed ke6bnl

 

I've used whatever is handy for butt welds..."C"-clamps and sometimes even tape, just to get the joint started. Those little clamps look pretty handy.

 

I have even used large speaker magnets to hold things in place at the other end of the weld. Ed ke6bnl

 

Thank you for the very helpfull information; it is greatly appreciated!