This page is about How to TIG weld 16 ga aluminum outside corner joint.
Thickness is .063 (1.6mm)
6061 t6 aluminum using 4043 filler metal .063 (1.6mm)
I recommend several tack welds on real world parts.
Imagine this small weld being on a larger expansion tank with several 90 degree breaks.
You would most likely need a tack weld every few inches.
Will the aluminum be heat treated after welding to strengthen it?
4043 and 5356 are the 2 most commonly used filler metals for tig welding 6061 aluminum.
4043 flows better but 5356 is typically stronger
But neither one of these filler metals can be strengthened appreciably by heat treatment.
4943 alloy will respond to heat treatment and so will 4643.
Certain critical or coded welds should have a procedure that has been qualified and approved by an engineering authority.
Will the weldment be subject to an anodized coating?
6061 is often welded with 4043 filler but when the job calls for an anodized coating after welding, 4043 welds will turn black.
5356 filler is a much better choice when welds will be anodized and cosmetics are an important factor in the end product.
Will the weldment be subjected to temperatures above 150f in service?
There are many applications where an aluminum weldment might be subjected to fairly high temperatures during service.
One example would be an aluminum aircraft engine part where not only does the part reach temperature above 150f but also experience stress and vibration.
Even though 6061 aluminum can be readily welded with 5356 filler and the welds are typically stronger than welds made with 4043 filler metal, magnesium in the 5356 filler metal can react with the silicon in the 6061 and at temperatures above 150f can set up a crack susceptible area.