Hi Guys My mag wheels on my 2007 Honda Oddysey are looking terrible so would like to get them tidied up. What prep is required before I can take the wheels to the powder coaters?
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Oct. 24, 2011 5:23 a.m. RTSomerville None
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Oct. 24, 2011 5:32 a.m. novaderrik Dork
call the powder coater and ask them.
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Oct. 24, 2011 6:18 a.m. mw HalfDork
If you have access to a sandblaster, you might get them done cheaper. At the very least, pull the valves and weights off.
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Oct. 24, 2011 7:37 a.m. Adrian_Thompson Dork
By Mag I assume you actually mean aluminium alloy, then I wouldn't have them powder coated. The powder coating heats up the wheel to the point where it can damage the heat treatment for the material and weaken the wheel. Lot's of people say never to do it.
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Oct. 24, 2011 7:55 a.m. ProDarwin Dork
Adrian_Thompson wrote:
By Mag I assume you actually mean aluminium alloy, then I wouldn't have them powder coated. The powder coating heats up the wheel to the point where it can damage the heat treatment for the material and weaken the wheel. Lot's of people say never to do it.
Is this an urban legend or no? Any articles on it?
I find it hard to believe... during track days its easy to heat the wheel into the "very berkeleying hot" range (well above boiling). Powder coating is in the 350deg range, and some powders can be done well below that point.
I'd like to know, because I may be looking to have some wheels powdercoated soon. Then again, new wheels are approximately the same price, so its usually much easier to go that route.
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Oct. 24, 2011 8:07 a.m. PS122 Reader
I've had really good luck with the specialized wheel paints that are on the market. Holds up really well and is much cheaper than poweder coat. Just remember prep is everything.
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Oct. 24, 2011 9:01 a.m. DavidinDurango Reader
Yes "prep is everything" . .
My powdercoater said he wouldn't do wheels because the powdercoat would fail (some years back). I took him brand new wheels and they have been fine.
Check w/ your powdercoater (already noted above).
I have rattlecanned two sets of wheels (one recently) - the older set lasted years. (prepprepprep).
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Oct. 24, 2011 9:19 a.m. Per Schroeder Technical Editor/Advertising Director
I think it's false economy to pay someone to sandblast and then powdercoat wheels (totally safe--how do you think the OEMs do it?) I just bought new Moda M10 wheels from the Tire Rack for around $110/wheel for my Odyssey and there were cheaper options.
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Oct. 24, 2011 9:45 a.m. Chas_H New Reader
Yup, many new wheels sport a powder coated finish, so the temperatures involved shouldn't be an issue. I had a set of Benz wheels powder coated last winter. I removed the tires, valves and weights and dressed up some curb rash applied by the PO. The finish came out very nice, with a few imperfections caused by contaminents lodged in pores in the wheel. I had the original wheels re-done because I couldn't find suitable replacements at an acceptable price. At the cost to re-finish of $75/wheel -what I paid-you might consider new wheels.
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Oct. 24, 2011 10:02 a.m. Adrian_Thompson Dork
From Keiths Targa Miata site about why he had to take a sledge hammer to destroy a set of 9UL's after having them powdercoated.
For those who want more details on the actual problem: as part of the T6 heat-treating process, these wheels are aged at 350F for about 18 hours. Powdercoating takes the wheels up to 400F for 30 minutes, which can "over-age" the alloy and make it more brittle. I've heard - first-hand - of a German NC owner that had the stock wheels powdercoated and they cracked on him.
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Oct. 24, 2011 10:05 a.m. Hal Dork
<--- The wheels on my Focus are the original stock wheels that I had powdercoated. They were 5 years old and begining to look bad. So I took them to a local place that makes decorative metal fencing that they powdercoat.
They sandblasted the wheels, masked up where needed, and powdercoated the wheels for $50 each. That was 5 years ago and they still look like the day I had them done.
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Oct. 24, 2011 10:31 a.m. ProDarwin Dork
Hal, thats cheap! I would gladly have it done for that price.
Adrian_Thompson wrote:
From Keiths Targa Miata site about why he had to take a sledge hammer to destroy a set of 9UL's after having them powdercoated.
For those who want more details on the actual problem: as part of the T6 heat-treating process, these wheels are aged at 350F for about 18 hours. Powdercoating takes the wheels up to 400F for 30 minutes, which can "over-age" the alloy and make it more brittle. I've heard - first-hand - of a German NC owner that had the stock wheels powdercoated and they cracked on him.
Interesting. Lots of track pads work well into the 1200F+ Range. I find it hard to believe at least part of the wheel isn't hitting >400F on track. Hell, many cars can get the rotors glowing even in an autox environment.
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Oct. 24, 2011 10:40 a.m. pres589 Dork
I remember Hot Rod having the F-Bomb powder coated as a primer... I hope they didn't over-age it.
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Oct. 24, 2011 1:28 p.m. z31maniac SuperDork
I know BBS specifically told me to use a low temp powdercoat on old RS wheels.
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Oct. 24, 2011 2:11 p.m. Keith SuperDork
I looked into this quite a bit. The engineers at Tire Rack said not to do it. Lots of opinions one way or another, but usually from those who didn't actually look at the numbers.
I wasn't willing to take the chance on a high speed race car. On a minivan, probably.
Most stock wheels are actually painted, I believe. But if they are powdercoated, it's possible the powdercoating was done as part of the aging process or they use a lower-temperature coating. I don't know what temperature wheels hit on the track, but it's the job of the rotor to absorb then dissipate heat. My wheels get warm to the touch, but not 400F+.
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Oct. 24, 2011 2:16 p.m. ProDarwin Dork
Keith wrote: My wheels get warm to the touch, but not 400F+.
Huh. I know I've accidentally hit a wheel with a tire sprayer and had the water instantly turn to steam. That has to be well above 212 F. Then again, track wheels tend to develop cracks after long term usage anyway...
We need a Mythbusters episode on this, stat.
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Oct. 24, 2011 4:10 p.m. pigeon Dork
I guess it's time to pull out the cheap HF infrared pyrometer and check wheel temps next time I hit the track. Sadly that'll be in April or May 2012
