Okay, so I picked these tips up from a variety of different threads and have no idea who to actually thank, but I just welded in a large repair panel on the front rear quarter panel on my '51 Chevy coupe and it went really, really well. Much better than when I did the same exact repair on the passenger side last Spring. Tips I got from the HAMB: Someone said "cut the panel to fit the repair, not the other way around. Only use as much of the panel as you need because they never fit right." So I did, and it was excellent advice. The brand-new panel was, in fact, not quite right and using less of it made things go better. I do not feel bad that I "wasted" the other 60% of the panel I bought. Someone said "cut the piece to fit with no gaps, you'll get less distortion." So I spent an hour carefully trimming and filing to get a nice, tight fit. It reduced distortion and made the welding much easier. Someone said "turn the heat on the MIG one setting higher than the gauge of metal you're welding so you get a nice, hot spot weld with good penetration. If you blow through, turn up the wire speed." THIS was GENIUS. Most of my spots got good penetration and at least half of them were perfect, with the same bead and heat pattern on both sides of the weld. I think it also taught me to do really short spot welds, which lead to less grinding when I was done. Someone said "start at the middle and work your way out." I modified this a bit, but what I actually did was work my way all along one side until it was done, and then started tacking on another side. That made it much easier to see what was happening to the metal as I welded. I used to tack all four sides and start skipping around. No more. That just locked in distortion. This way I could, for example, see the bottom moving around a bit while welding the top and not have to worry about buckling. Someone said "work out distortion as it occurs, and THEN continue welding." Actually, I've seen this in more than one place but it had never occurred to me before reading it. I used to keep going and then try to fix it all at the end. Now a little too much shrinking = stop and stretch the metal BEFORE doing any more welding. ONE I FORGOT when I first posted this: Someone said "Use .030 wire in your mig, you'll get less distortion." It did seem to help - the wire speed would have been awfully high if I'd been running the .023 in there! The result is a panel that, if I do a little hammer and dolly work, will actually be metal-finished. That's something I've never done before. So, THANK YOU to everyone who contributed any of these tips anywhere on the HAMB!
Amen! I didn't generate any of this knowledge myself, I just gathered it over the past few months and then applied it this past weekend. I was stunned at how much difference it made.
I'm glad I got this all figured out now, when I'm just getting started on this particular car, but I wish I'd learned it all a couple months earlier, BEFORE I spent hours fighting the same repair on the other side of the car! It did make for a nice A/B comparison, though: hours and hours of pounding vs. none for the same result end result. I felt like Happy Gilmore: "That was so much easier than putting. I should just try to get the ball in one shot every time!"
Warning Will Robinson! Warning! Some times the planets just will NOT line up. Don't get me wrong, this is excellent operating proceedure and will ease many a tough job. I just have to be very careful, because when I get it all figured out some thing jumps up and bites me. Your results may vary.
Who weclome to the club of rust fighters. Keep up the good work. Just remember sheet-metal welding is like getting to Carnegy Hall......................practice, practice, practice.....
Your approach is very good. Yet be careful when you go to finish with your hammer and dolly. Mig welding creates a hard finish does not become malleable like ocy/actylene welding. Mig welding is HARD and does not "move" around. Still a great way to put a panel in however MIG welding is normally used for newr cars where minimal heat is needed to not disrupt the Make up of the steel - new cars are not constructed from mild steel
Post #11 and I'm the first to say....... "without pics, it didn't happen". Glad to hear it went well.
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