for some reason i cannot butt weld 16g alum together. my surfaces are clean and the sharp edge is taken off. there is no gap and i cannot get it to puddle together. does someone have any tips? im using an older 175a linc tig. 70-75amps with the gas at 16. 3/32 tungeston and 1/16 5356 rod. im desperate and getting frustrated. the torch is at the 20degreeish angle. i just have no clue. any help would be greated appreciated!!! what is happening is that a puddle on the edges of the two pieces start to puddle and when i apply the rod, the dab balls up. if i go hotter on the gas the damn thing starts to push the heat into the pipes and either creates a hole or turns into mush.