Bicycle Mechanics - Will paint stripper destroy anodizing?

I've just bought a "shop soiled" anodized Dedacciai 7003 (alu) frame very cheap, which has ugly yellow bits painted on some of the tubes.

I wanna get the yellow paint off these bits because it's anodized underneath.

I'm hoping the paint stripper will take off the paint and leave the anodizing nice and shiny.




Thanks

Well, it's three hours later and I couldn't wait.....
Unfortunately, the answer is "yes", but only in patches. :D :(

I tested a patch along the inside of one of the chainstays, and it took off some
of the anodized plating, or whatever it's called.

D'OH

Do not try this at home :)

531Aussie

I'm sorry mate, I've just seen your post.

Anodized Aluminum has 'chemically' treated surface - ie anodized aluminum has a compound surface.

Paint strippers are often very strong alkaline agents and so more than likely WILL damage Aluminum or it's compounds (eg anodized surface).

Manual treatment of the surface (eg sanding) is also likely to damage the andoized surface (it's relatively thin and POROUS in structure).

If there are HIDDEN patches/areas that you can TEST this theory, then please carefully try heating/flame the painted patches cleanly - you may be able to burn/peel off the paint - but again it depends on the anodized surface color - the darker the color the better!

Good luck.

Thanks.

I'm gunna painstakingly get the yellow paint off the painted areas without
damaging the nice shiny anodizing underneath.

Maybe, after sanding as close as I can, I could use a "thinner", or "metho" to wipe off
the last bits of undercoat -- I've already done this on one spot, but it took ages.

I see Archie already hit the high points of what I was going to say. Since an anodized coating is only a few microns thick, often it can be 'polished' off. Automotive rubbing compound and steel wool usually does the trick. If it's a convoluted part and you don't mind spending a few bucks, glass-bead blasting should work as well.

MSWANTAK - we're not worthy pal. Cheers.
531Aussie - there's always the option of cleaning to the bare metal and then anodizing/surface treating the parts again! . . . how much have you got? (joke) :-)
How about a total repaint/re-spray (DIY job)?
Best wishes.

I wouldn't touch an Al with stripper. Ever put Al foil in Drain-O (potassium hydroxide, a very strong base)? The Al dissolves in seconds.

If it's solvent based it's safe, if it's alkali based, DON'T DO IT - aluminium oxide dissolves in strong alkalis. Test? Put an anodized bike part in caustic soda (lye?) and the colour can be rubbed right off :eek:.

MSWANTAK - we're not worthy pal. Cheers.
531Aussie - there's always the option of cleaning to the bare metal and then anodizing/surface treating the parts again! . . . how much have you got? (joke) :-)
How about a total repaint/re-spray (DIY job)?
Best wishes. Thanks again. I really like the colour of the anodizing -- it's
sort of of shiny platinum looking thing -- so it should look good with whit decals.
If worst comes to worst, I know a panel beater who paints bikes (one colour) for about $70US






I wouldn't touch an Al with stripper. Ever put Al foil in Drain-O (potassium hydroxide, a very strong base)? The Al dissolves in seconds.

If it's solvent based it's safe, if it's alkali based, DON'T DO IT - aluminium oxide dissolves in strong alkalis. Test? Put an anodized bike part in caustic soda (lye?) and the colour can be rubbed right off :eek:. The stripper is 870mg/L methylene chloride. I sucked at chemistry, so I wouldn't wanna guess it that's an acid or a base.......hmmmmm...acid? Gives your skin a nice little sting.

Is there a paint thinner that will break down the last bit of undercoat?

Thanks

The chloride part is the tip-off; chloride = salt = alkaline. As far as thinner, if xylene or toluene won't take it off, I don't imagine any solvent will.

Thanks again