I am re building a tube frame race car panelled in ali sheets that were powder coated pre riveting. If I un-rivet the panels, many of which are quite intricately formed, is there a safe way to remove powder coating from fairly soft grade alloy sheet? I then want to re powder coat them, probably in a different colour to the black which they are now. Most have had some abrasion that has rubbed through the powder coating, some have a bit of fretting around the odd rivet.
Chemical stripping is probably the easiest, but not exactly the safest.
When I was working in the aluminum finishing plant, we used to get some dud parts that needed to go around again. We used a large tank of methylene chloride-based stripper with a water cover to do the job, it usually took about 4 hours to get the powder coat loose enough to hose off so they could go through the powder-coat process again. This was on polyester and epoxy coated parts. I've not checked availability lately, but locally I could get aircraft finish stripper from a auto body supply shop, this was about the most potent stripper that was readily available without going to a chemical warehouse and compounding my own. Gloves and eye protection mandatory, chemical boots and suit recommended. It should take off just about any organic coating.
Be aware that powder coating needs about 450 degrees F to cure, probably OK for your panels, might not be good for load-bearing items, though. You might want to consider going to a regular automotive finish system after stripping, it'd probably be easier to maintain and durability would probably be as good or better than powder coating. Stan
There's a lot of different grades of paint stripper, the grades you can get at the hardware store usually has very little of the good stuff in it. The more you spend, the higher the concentration of methylene chloride. The aircraft finish stripper I was using had a concentration of about 30% methylene chloride and was about $30/gallon. The hardware store stuff didn't even start working on the car finish I was trying to remove. 15 minutes with the good stuff and the finish popped off with a sound like frying bacon. The stuff we got at the finishing plant was over 75% methylene chloride, I don't know what that cost per barrel. There was probably 400 gallons in that tank, though.