by chuckthebeatertruck » Sun Jan 23, 2022 9:48 am
I never learned how to wire weld iron and don’t trust myself on thin sectionals. So, I usually use silver solder. Harris safety silv40 and safety silv flux. A turbo torch is borderline, but a small oxy/acyt set works for fin repairs.
Depending on number of fins, sectional thickness, size of break, and where on cylinder, I may or may not preheat much beyond the join. Small repairs I generally don’t but more extensive ones I heat the cylinder to “uncomfortable” and start from thinnest and smallest to thickest and largest fin. I do use a very hot high o2 flame cone to burn out impurities before dialing it back and fluxing for the join.
Cool it slowly. Stash it in a warm oven, bury in some sand, flip a pail and welding blanket over it, etc. Flux wipes off with hot water.
Check your bores after and hone as needed.
Fin repair is fun, really.
I also have used industrial grade epoxies. Works surprisingly well for sticking fins on and filling. I like lab metal for filling in any lines at the join. Some guys will flow more silver or even a small amount of pb-free soft solder to totally hide the join.