Would like more info & detail on using the silver solder and JB Weld!
Silver bearing solder (like Harris StayBrite) is a fluxable solder (uses an acid flux) and will join not just copper, brass and metals in that family but also ferrous metals. And it will solder them very well and as strong as goat's breath. The benefit is this solder melts at about 450 F, so you won't be warping things or blowing holes in metal, etc and when you're done, you can grind/sand it in the same fashion that lead was once used. It isn't cheap, but no solder sold today is cheap. One of the neatest ways to use this is to get a pair of Vise Grip flange pliers. Use those to make a flange on the piece you're soldering to and then cut the part you're replacing to fit nicely on that flange. Then clean both pieces, add flux (will be like water but acid), heat and solder. When you're finished, mix soda in some water and pour it in/over to neutralize the acid. And in a fraction of the time and a fraction of the irritation/confusion, you're done. Say for example you're replacing the bottom 8 inches of a door skin. Measure and cut, leaving an extra 1 inch for the flange (or whatever size your pliers are), use your pliers to flange the door and then set the new piece on top. Add flux and solder away. With no more heat than you're using, it isn't going to act all funky on you. It will just sit there and behave until you're done.
As for J.B. Weld, I do the same basic thing but if you don't have flange pliers or if the area won't be compatible with those, cut a piece of the same weight metal to be a back-up plate for you. This will go around the inside of the piece you're epoxying to. Let's say you're replacing a radio cut that somebody made a mess out of. You'd clean that up, epoxy the back-up plate behind the cut and let it set. Some of the J.B. Weld will set in 6 to 8 minutes, so keep that in mind. You may want to make 4 back-up pieces if you are working on a square or rectangular piece. That in essence will be your flange. Once that sets, then apply epoxy to the back-up piece and the piece you're attaching as the replacement, get it all aligned correctly and use a piece of masking tape to hold the pieces in place. When that sets, remove the tape, give it 24 hours to fully cure and you can sand the seam just as if you had used Bondo. You can use either of these approaches in either areas subject to stress or areas (like your radio cutout) which see no stress or very little stress. A friend of mine once cut a rear fender in half (top/bottom) and cut another in the same place (one without damage on the bottom), joined both with J.B. Weld and the seam never gave him any problem. It took him two packages of J.B. Weld to do this, but how much does that cost? $6 for a package? That's a lot cheaper and easier than welding and...J.B. Weld will never rust. Besides as I said before it is a heck of a lot easier to grind/sand/finish.
Please don't get me wrong. I was trained as a welder and have done it professionally. Welding is fine, brazing is fine...but it is just like I would expect performing surgery is. The more you do it, the better your work gets.
