Welding Tips and Tricks

Powder coating is tougher then I thought. Tried scraping it off with and without heat and just made a mess. Tried my 4" grinder with a wheel and the paint smeared like snot. Going to Harbor Freight today and buy some cheap flap disks to try so if they load up with snot I won't mind throwing them away. I'm worried about contamination from grinding the paint into the aluminum.

Powder coating is a royal PITA on any material but aluminum will cause major issues - if you try to grind it / flap wheel it it will smear & keep contaminating the surface - only way I had any luck is to cook it well with a torch then shot / sand blast to bare metal - you cannot skip the torch bit as it really won't blast as is - if at all possible don't weld something that is already coated !

Use chemicals (Aircraft Stripper) to remove the powder coating. Then clean the aluminum well with Acetone afterwards. Flap disks will only drive impurities deeper into the aluminum. Heating the powder coat to remove it will cause the underlying aluminum to draw impurities before cleaning off the powder coat.

Yes, it is very tough stuff-

Might even try freezing it before the flap disk. That might allow it to sand off without smearing. The harder you press it with a grinder the hotter it gets and starts to soften then smear.

If you're willing to use a really nasty chemical, methylene chloride will remove it quickly. I'm not sure how easy that is to get any more, and if you get some be careful with it. The next best choice is anything with methanol in it, I've used stuff I think was called Kleenstrip, that's what was available locally and it worked good. It will help a lot if you use rough sandpaper to scratch up the coating first, but if you're concerned about scratching the aluminum that might not be possible. To remove the coating after the stripper has soaked, use brass brushes, they won't scratch the aluminum.
Don't use anything caustic (which works well on steel) because it will attack the aluminum.

Sandblast it.

give it to my grandson son for five minutes and
he will have every inch of finish wore off it.
craig