ggodwin

Can someone tell me if there are any key difference when welding these two types of aluminum?

I am assuming that I should not be able to move from one material to the other with out some weldability impact.

I weld my seat stays together near the seat tube prior to welding them to the seat tube. I cant get them to weld together now.
Basically I fixture the two stays up and connect them at the top. This allows me to assure they are flat and the brake mounts are perfectly aligned. Then I mitre the two stays just one time and it fits perfectly.

The stays are thinwalled 7005. It seems that the torch just wants to burn through it rather than puddle. However, I have no control of the beads. They have black specs and the TIG Cone seems to have a "spackling" noise rather than a smooth sound. However, if I move to some small 6061 plate as a test everything is fine. If I am welding heavier gauge butted up to on the seat tube or drop out it is not as bad. I move the puddle onto the thin stays and make it work. Not as smooth but welds, but it works.

I called the tube supplier and they tell me that no other frame builder has had the same problem.

Opinions please

MassiveD

I have no idea, Frank will be by. Do you have the same results when fusion welding as when using filler, and are you sure you have the right filler. Other problems can be bad gas or too little or too much gas, are you using a lens. That should add some more for when the adults show up.

Henry III

Aren't black specs usually contamination from unclean material or filler material? If it's thinner stuff what about using pulse if you have the option to keep from overheating the puddle. Maybe consentrate more on the seat tube which should be thicker then the stays to keep from burning through?

MassiveD

Yeah, that is what I would imagine. But it is weird that the 6061 would be clean if he is running the same process. There are many ways to contaminate a sample though.

ggodwin

Yes, I always work from the thick to the thin. But, this occurs even when thin on thin and amps cranked way down.


This may be a basic fundamental "NO-NO" of TIG welding Auminum tubes that I have missed.

The appears to only occur when I am welding the "Open Ends" of tubing. Whether or not the the joint it to another tube or a plate, the same dynamic occurrs. If I start the bead away fron the tube ends it is fine until I arrive at the ends. Once I get there all **** breaks lose.

Has anyone ever dealt with this problem before?