On 3/7/2018 6:52 PM, Frank Krygowski wrote:
Our ancient (1986) Cannondales could use some refinishing.
The paint has bubbled and chipped in places, exposing the
aluminum. The bikes aren't grossly ugly, but they're far
from pristine. I think the original paint is DuPont Imron,
or some similar catalyzing paint.

I was given information about a local place that does a good
job with powder coating, and is not very expensive.

But I got to thinking: The bikes are 6061-T6 if I remember
right. And I think powder coating gets baked at a higher
temperature than the aluminum did. I'm finding that T6 heat
treatment involves about 350 degrees Fahrenheit, but powder
coating uses about 400F. That makes this sound like a bad idea.

Is there something I'm missing?


Right you are. The T-6 state will be lost between 350 and
400F. Retempering is not feasible because you're up in the
950F range where the powder finish will be lost and the
quenching from that process is very likely to warp or crack
your closed-figure frame. Krylon maybe?

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Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971