From what i have noticed, temperature is key. You want to have the temperature around 730ish degrees. The material (Brazing Rods) will melt at much lower than that. I think it is in the area 550 degrees? Get the metal hot and allow the rod to melt on the clean, roughened surface. This is the tinning stage. With a Stainless Steel Wire Brush, smear around the melted rod as soon as you remove the heat source. It should leave a coating of the rod. If it doesnt, then your tinning was done wrong and repeat. Also, never melt with rod with the flame, let the heated metal melt the rod. Hold the flame about 1/2 inch from the brazing rod and about 2 inches from the base metal. This is a good indicator that the base metal is hot enought to accept the brazing rod whent eh base metal will melt the rod.
Now that we have that out of the way, I would say get everything welded over using these Rods. For small wholes, the rods are ok but cracks, they really need to be welded. I TIG welded all of mine and i can say with 100% certainty that the tig welded spots are far stronger than the brazed ones that i did testing with. I tig welded all the cracks and then placed a .060 patch on top of that. I have no doute that it will never leak in that spot again. If you have a tig welder, all you will need to do to weld aluminum is get a "Green" Tungstan (100% Tungstan) and switch your power type over to AC and go to town. Hope this helps
