Powder-coating?
 

I was going to get my track frame powder coated but someone told me that it weakens the metal. Does anyone know anything about this? Is that true?

The only thing I can think of is that a little bit of metal comes off when they blast the frame before painting. Otherwise, it's just paint that's baked on. It doesn't weaken anything.

Check this thread out:

http://bikeforums.net/showthread.php?t=378838

Very informative. He sounds like a nice chap, too. I'm sure he'd answer any further questions.

Thanks

Wow, that guy is awesome. Hanging around in here all day you forget what its like to be around people who know what they're talking about. :P

/\ /\ /\ Quality. /\ /\ /\

if you take a piece of raw steel and bend it, it'll make a 90 degree bend easily
and it'll hold that shape, now take that same piece of steel and heat it till it's red hot (750+degrees) and then quench it in cold water,......now try and bend it,.....more than likely it'll snap into two pieces, because the heat/quench has created martinzeiss steel(forgive if I spelled it wrong), NOW,...take that SAME piece of steel and heat it gently to about 450-500 degrees (close to powdercoat temprature) and then let it cool slowly (no quench), NOW try and bend it, and you'll find that it bends, but will snap back like a spring.

so I guess the real question here is:

will the heating and slow cooling of the powdercoat process RE-TEMPER the steel? or will it SOFTEN (anneal) the steel?
(I SERIOUSLY doubt you could remove significant amounts of metal by blasting, unless it's soft aluminum, and you are using carbide as the media, which will never happen in the real world, so that point is moot IMO)

and this needs to be answered by a metalurgist, or a machinist with good metalurgy knowledge, or a frame builder, and NOT by a powdercoater (no offense to any powdercoaters out there) as I personally would like a qualified answer simply because of all the internet MYTHS out there.


someone please answer this, and put this to rest.

When this person told you it would weaken the metal, he was probably talking about the (sand)blasting process. The dange, or lack thereof, in blasting depends on the medium.

I've heard that there's more risk of weakening aluminum with blasting, so they use walnut shells (or a few other options) as opposed to sand. I don't know if there's also a benefit/reduced risk in blasting steel with these alternate materials (not sand).

Here's a FAQ from a well respected powder-coater here in Colorado Springs:

http://www.spectrumpowderworks.com/s...D&fadeIn=false

If I were to get my frame powdercoated, would I need to reface or ream the headtube before installing a new headset?

you need to reface the headtube and the BB after the frame is powdercoated

It depends all how well the frame was masked. I had to do a little bit of filing on my fork where the bottom piece of the headset seats, but other than that everything was good to go.

Take it to a place that knows what they're doing and you won't have to reface anything. Also, most modern powdercoaters don't bead blast anymore they chemically strip which keeps the more pristine.

The temperatures and times involved in powdercoating are not high enough to affect any aluminum or steel frame.

Steel (4130 Cr-Mo) anneals at over 1500° F, and hardening heat treatments soak at close to 1000° F. I think powdercoating ovens are more like the 400° range.

6061 Al anneals at 775° F, and it's possible to precipitation harden at 320°, although it takes 18 hours and then another 8 hours at 350°. For powdercoating, a bike frame would probably be in the oven for 45min or less.

At my work, we send Al out for powdercoat all the time and there is no real concern for the PC process to affect the strength of the material.

*Info was from these links:
http://www.suppliersonline.com/propertypages/4130.asp
http://www.suppliersonline.com/propertypages/6061.asp