Yep, the wheel will deposit particles into all the fine scratches it leaves behind. If the alum is very Oxidized you should use a very fine stainless brush to clean the weld area then go over that with a cleaner like we have been discussing here. I'm doing Mild steel still so the Powered wire wheel followed by a wipe of Min spirits has been working fine. By the time I'm outta bed I will have gone back a few paces in my practice I think.

Will make some new practice Pieces out of some of that rusty old 3" .250 channel my dad got. It's very rusty so will have a lot of cleaning to do with the wire wheel or even the paddle wheel sanding discs. Still a couple weeks away I think though. I refuse to buy metal to practice on