[TowerTalk] 6061 vs 6063

[jimlux]

> As a rough comparison, the springy  Aluminum alloys are much like a 
> steel spring. They can be bent, but exceeding the minimum bend radius  
> (which can be quite large) will end up fracturing the material just like 
> bending a flat  coiled spring too far will cause it to break or shatter 
> at the bend.
> 
> With the advent of TIG welding, the ability to weld Aluminum has become 
> far easier. Oxyacetylene welding of Aluminum can be done, but takes 
> practice (One that I never managed to master). Even then it's easy to 
> get a "granular" weld which is not all that uncommon on Aluminum tower 
> cross braces.  The reason "Torch welding" is so difficult with Aluminum 
> is the ability of Aluminum to transfer heat.   TIG welding creates a lot 
> of heat concentrated in a small area from an electric arc.  The welding 
> rod is fed into this arc with the two making the weld relatively easy to 
> control. 
> 

Aluminum is difficult to weld for another reason. Unlike steel/iron, 
which turn red/orange well before they get to the melting point, 
aluminum melts at a low enough temperature that you can't tell by 
looking how hot it is.  The visual cues are important (and with a good 
TIG welder with foot pedal control, you get good at it, at least that's 
what I'm told.. I'm a terrible welder)

And, oxidation is a big issue with torch welding.