Acid flux I really easy to kill ,tin was the prefered methed of putting ribs to barrels tin has a similar contraction expansion rate as mild steel ,I know people who use a clamp system but you can push the rib down between the barrels if you are not careful. my electric iron is 350,400 watts I use it to tin everthing before wireing up ,like I was told there is more then one way to skin this cat