[Og Neon]

This probably belongs in the Wheels forum, but I am looking for anyone that has had a similar experience after powder coating their wheel.

I got my ZLE wheels powder-coated bronze to change up my track theme this year. They looked so fricken good and after pickup, I immediately went to my tire people to install some fresh rubber. After seating the tires, the metal began to bulge. Something went wrong in the coating process and significantly weakened the wheel. I'll let the pics do the rest of the talking. Any thoughts or advice from those smart on metallurgy? Obviously, that wheel is toast, I don't think I will trust the other wheels to do track duty. I guess the powder coating rumors may be true!

This puts a huge crimp on my One Lap of America prep though!

[Smokin19]

Not any authority but, I would quess too hot of heat in the baking process.

[RobZL1]

Yep. They cooked those puppies.

[Tay]

That is because of a bad powder coater. Those wheels are destroyed.

You should never powder wheels if you plan on tracking. It can weaken the wheels.

You should only ever paint the wheels. Any competent body shop can paint wheels.

[onelfastlride]

From memory, I spoke with a materials engineer about a set of BC Forged rims, the take away was he strongly recommended against powder coating forged aluminum rims. He even mentioned a friends race team that had multiple rim failures. After, they consulted him it was discovered they had powder coated multiple sets of rims.

The links below may not directly apply to the material composition of the factory forged rims, but it gives a general idea.

Section 2.) Defining Thermal Stability of Structural Materials and Aluminum. “ At temperatures above 150 °C, the alloy suffers a loss in strength with deterioration increasing over time. Above 200 °C, the weakening is substantial, and is accompanied by some gain in ductility.” This may not be the exact temperatures for these forged wheels, but perhaps in the range and provides general information about aluminum alloys.

https://www.ncbi.nlm.nih.gov/pmc/art...in%20ductility.

Then look up at which temperatures powder coating is baked. Again in general, “ Powder coating ovens must be able to sustain temperatures of 450°F and the oven will need to be large enough to fit all the powder-coated objects inside.” 450 F = 232 C.

Putting the pieces of information together, you can possibly see what happened in this case.

[hawk02]

Whoever did the powder coating must not have a lot of experience doing wheels.

Forgeline powder coats their wheels and says if done correctly it provides a superior finish to paint. See post #6 in this thread:

https://rennlist.com/forums/996-gt2-...ls-please.html

I believe custom-color HRE wheels are also powder coated.

I had the OEM wheels from my 2013 ZL1 powder coated by Wheel Medic (one of the recommended shops by Forgeline) here in Columbus and never had a problem. Granted, I never tracked my ZL1. My only complaint was the gloss finish made it easy to create swirl marks if not properly cleaned.

I think I would go back to the powder coater and demand some compensation for destroying your wheels.

[ZLRob]

I officially despise powder coating after dealing with it chipping, abnormally fading and just looking generally stupid after it's all said and done.

For your next set of wheels, traditional paint is the only way to go, especially when you are talking about the track where any modifications you can make can either make you or break you while you are in the beginning, middle, or end of your course.

[clyde]

Originally Posted by Og Neon

This probably belongs in the Wheels forum, but I am looking for anyone that has had a similar experience after powder coating their wheel.

I got my ZLE wheels powder-coated bronze to change up my track theme this year. They looked so fricken good and after pickup, I immediately went to my tire people to install some fresh rubber. After seating the tires, the metal began to bulge. Something went wrong in the coating process and significantly weakened the wheel. I'll let the pics do the rest of the talking. Any thoughts or advice from those smart on metallurgy? Obviously, that wheel is toast, I don't think I will trust the other wheels to do track duty. I guess the powder coating rumors may be true!

This puts a huge crimp on my One Lap of America prep though!

Wow! Sounds like it happened after both beads were seated? What tires and what PSI did it take to get them to seat? (Kinda wondering if they might have been RE-71RS that took a ridiculous amount of air.)

Hope you have other wheels you can run for One Lap!

[Mark R]

Wow. I have never heard of or seen this, but yours is a cautionary tale for anyone who is contemplating powdercoating wheels.

I hope the powdercoating company makes you whole.

[kropscamaro16]

holy shit and yea ive been told not to powdercoat my wheels to only paint them or some places used a special process or lower temp but wow thats wild...

[Rock-It Man]

Forged wheels get their strength from being forged to scramble the crystalline structure. Heating and slow cooling of forged aluminum results in annealing, making the material softer and weaker by aligning the crystaline slip planes.

Possibly there is a temperature/time for powder coating that does not result in annealing, but I would leave that to wheel fabricators, not Shade Tree Powder Coating, Inc.

[JTS]

Annealing the Aluminum back to an O soft condition. I formed mostly Aluminum and Steel, for 16 years, Aluminum in n the O condition, is very soft and can be formed to the configuration, before it needs to be Heat Treated in a solution of Sodium Nitrate @ around 700 deg. 6061 , 2024 an 7075 all have different times in the solution to reach the T6 condition .
Forged or milled is a lil different, but bottom line here , the heat reverted the Aluminum to the O condition.

[Vtor_ZL1]

That's wild.


Recalls my garage efforts of reusing aluminum oil pan gaskets by hitting them w MAPP torch. Dead soft in seconds.

[Badmojo]

Thanks for posting this. That could have been bad if at speed on track!