[emlclcy]

one of my jobs (not welding related) is to prototype touchscreens for phones. The basic process is to laser a pattern in the ITO (indium tin oxide conductive coating) then print 'crossovers'. after much trial and error i found the surface energy of the ITO was lower than the surface tension of the thing i was printing so it balled up.
Passing the ITO screen through atmospheric plasma (atomically cleans the surface and embeds oxygen atoms in the surface) had the effect of raising the surface energy making the inks i'm printing wet.
what’s all this got to do with welding?
well, i've not tried this but if you have a plasma cutter and up for trying this, set the power pretty low, hold the plasa jet about 2-3" away from a piece of say aluminium and wave the plasma plume side to side just once over half the test piece then try TIGing a bead through the treated zone to the untreated to see if there is any difference.
worth 5mins to try hey?

carl

[Otto Nobedder]

I suspect your idea (haven't tried it) would be counter-productive. The point of grinding/cleaning Al before TIG welding is to remove oxygen from the surface. Aluminum oxidizes readily and rapidly, and the heat from the plasma torch mixed with stirred-up atmosphere would likely accelerate this. The oxide layer is the enemy due to it's very high melting point relative to pure Al.

I might try it anyway the next time I weld Al. The difference between theory and practice is that, in theory, they are the same. In practice, they seldom are.

Steve