Re: powder coating aluminum frames



were those extrusions heat treated before?

I thought that heat treating of a typical aluminum alloy used in a bike
frame was done at something like 1600 F.


<almost_fast@xxxxxxxxx> wrote in message
news:1184625591.043666.181500@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jul 16, 1:45 pm, zencycle <zency...@xxxxxxxxxxxxx> wrote:
I was recently asked a question - do the high temperatures in the
powder coating process adversely affect the characteristics of the
alloys used in aluminum frames?

Possibly. Some aluminum extrusions I worked with showed unacceptable
degradation of alignment after going through powder coating. We
checked with a CMM before and after, a batch of 50 parts.

I seem to remember seeing powder coated Al frames on the market,
though I can't recall any specific examples. It seems to me that you
would need much higher temperatures than typical powder coating
(400degF) to cause any damage to the tubes, but there are MFRs of
engine parts that recommend against powder coating the alloys used in
their products.

Any ideas?

We turned down the temperature and tolerated the distortion. I always
worried about the structural properties, but the parts passed fatigue
testing. That's not the same as saying they were "as good as" the
anodized version, though...



.



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