Repainting a frame?

20 years ago, I've used Circa Paint and varnish remover on a Kona Stuff hardtail aluminium frame and like others have said, the paint just bubbled and lifted off easily. I then brushed it all over with steel wool, cleaned the aluminium properly afterwards and properly masked the threaded and press-fit interfaces. I sent it to a factory that was doing powder coating and they just ran it into their regular "white" parts batch (I could only choose between white, grey and beige).

The frame held up to a lot of dirt jumping and what I'd consider fairly hard riding (30mm over-forked too). At the time, it never occured to me that the paint remover or the powder coat uring temperature could have harmed the frame, but nowadays I'd check all of those details carefully before proceeding.

Still, I was much happier with my white frame than with the original translucent-fluorescent-yellow paint job haha!

Posted by: Ouch

Posted by: FLATCH

Posted by: T-mack

Don't sandblast aluminum frames! Years ago a buddy did, painted it, built it up and a minute into the ride the whole bike folded LOL. Makes the thin aluminum even thinner. Instead use aircraft paint stripper. The stuff is super aggressive so use it in a ventilated area, then clean the frame in acetone after.

^ ^ this! I’ve used it and it’s amazing. Brushed it on liberally. Half an hour later hosed it off and 95% striped. One more time in the nooks and crannies and done.

Is it really necessary to strip the paint? I've also read that sanding the original paint slightly is all that's required.

That aircraft paint stripper must be nasty stuff to work that well!

According to the spray bike site, you can just sand the frame, which avoids the need to paint a primer coat. They also mention that paint removers can leave residue that prevents the new paint from adhering.

Posted by: RAHrider

They also mention that paint removers can leave residue that prevents the new paint from adhering.

Hence the need for acetone after.

Posted by: T-mack

Don't sandblast aluminum frames! Years ago a buddy did, painted it, built it up and a minute into the ride the whole bike folded LOL. 

How hard did you laugh when that happened?

Posted by: T-mack

Don't sandblast aluminum frames! Years ago a buddy did, painted it, built it up and a minute into the ride the whole bike folded LOL. Makes the thin aluminum even thinner. Instead use aircraft paint stripper. The stuff is super aggressive so use it in a ventilated area, then clean the frame in acetone after.

walnut blast works well on alu frames; removes finish without abrading the metal. i've had a few frames done over the years.

Posted by: syncro

Posted by: T-mack

Don't sandblast aluminum frames! Years ago a buddy did, painted it, built it up and a minute into the ride the whole bike folded LOL. 

How hard did you laugh when that happened?

Yes

Yeah walnut works fine. After using chemical stripper and scraping with a 3 sided knife I used to lightly go over aluminium frames using glass bead in the blasting cabinet for an easy clean up. 

But as above if original paint is well adhered one can aggressively tooth it up and paint over.

A timely thread. 

I'm considering having my steel frame acid dip stripped then powdercoated. 

Or go cheap (and likely low quality) by doing a rattle can job myself.  

Mind you the price I got given by the powdercoater was approx NZ$200 which I think is pretty bloody reasonable actually.