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Alloy Frame powder coat myth?(7 posts)

Alloy Frame powder coat myth?desmo
Nov 18, 2003 10:14 AM
I've been told by a couple of people that it's not a good idea to powder coat aluminum frames as it may affect the heat treating of the tubes. Anybody have some actual facts about this? The frame is a Kona cyclocross made from 7005. The bike gets beat like a stepchild so I would really like to get it powdercoated, as regular paint would not hold up for long.
re: Alloy Frame powder coat myth?MShaw
Nov 18, 2003 10:31 AM
If that's the case, why would they powder coat Yetis?

It usually depends on how hot they get the oven, but overall, I'd say you're safe.

Ummm, big myth.jw25
Nov 18, 2003 10:34 AM
Heat treating of aluminum alloys takes place fairly close to their melting point. Pure aluminum melts at 1220 degrees F, and 6001/7005 should be close, if not higher.
Powder coating takes place at the melting point of the plastic powder used.
The two temperature points should be at least 800 degrees F apart. Given the number of powder coated frames from Santa Cruz alone (all made of aluminum), I think your Kona will survive. Personally, my concern would be frame prep, as an aggressive prep can start removing material, which would weaken the frame. This is more common with steel frames, since they're blasted to remove rust, but I'd use a coater with bicycle refinishing experience. Shouldn't be too difficult, as there's plenty out there.
Nov 18, 2003 1:39 PM
Most heat treating for bicycles does not occur near the melting point of Al. Of all the tubing in the Columbus catalog, all but one (Starship) are heat treated in the 130 C to 150 C range (that's right about the same temp. as powder coating). Now of course most mountain bikes are not made with Columbus, but if one premier tubing company heat treats their tubing at no where near the melting point of Al, then I'd say there's a fair chance that other tubing manufacturers are similar. I'm not saying that it can't be done or is not done, I just suggest that the poster should check with the frame builder........frame integrity is too important to make a blanket statement like that.
depends....Rusty Coggs
Nov 18, 2003 3:31 PM
...on he alloy.6061 and the like are HT at much higher temps than 7000 series.
Rubbish! Here's pics of my recently powdercoated Cannondalerussw19
Nov 18, 2003 1:25 PM
It used to be a Saeco Team Replica, but I got sick of seeing so many others on the road. That and I didn't like the shade of red, so I had it powdercaoted a British Metallic Green with some Gold fleck in it. It doesn't show up very well with my camera because my camera is pretty low resolution. I wanted more of an Emerald Green, but they had this color in stock and I wanted to get it done.

Oh yeah, and for anyone who read the "How long should wheels last" thread, those are the same Open Pros with 42,000 miles on them.

re: Check what says...nmRusty Coggs
Nov 18, 2003 3:33 PM