Ever try making a welding repair with Durafix Aluminum-Zinc welding rods?
Technically it is not welding. but is actually more like soldering.
No flux is needed...and you can use any type of torch that will heat the metal to 730 degrees F.
In this demonstration, a soda can is repaired. A large hole is punched in the bottom of the can to show how well this rod will fill a hole. You can imagine that this would be a fairly common type repair on aluminum canoes or rowboats, aluminum radiators, evaporators, valve covers, etc.
Because flux is not used it wont contaminate the inside of a radiator or evaporator. The key step is to scratch the rod on the surface to break through the aluminum oxide coating and make the metal flow like solder. Trying to melt the rod itself is a sure headache.... Just like when soldering copper pipe.
Seasoned welders sometimes overlook this easy method to weld repair items like alternator housings, aluminum boats,etc.
But the end result is sometimes a better repair than could be made with a TIG welder. Thats a pretty bold statement but its true.
TIG welding any kind of aluminum casting that has been exposed to oil is a problem.
Cleanliness of the surfaces to be welded is always a big deal on aluminum whether tig welding or brazing with aluminum/zinc rods.
Take a broken ear on a transmission housing for instance. For some simple repairs like replacing an ear or lug that got broken off by a forklift or something, using Dura fix easyweld rods make for much less headache. Why?? because you dont have to get the part nearly as hot and because Durafix is very fluid and able to be "cast" into place with steel backing. Remember this stuff will not stick to steel so steel works great for a stop off backing material to help shape the repair.
Once the repair is made and cooled off , it can be ground, filed, drilled, tapped etc and is often stronger than the base material.