Wheel Powder Coat Damage

[crowe]

I've just booked my back wheel 'n' other bits to get powder coated.

My qustion is, can the heating process of powder coating damage my wheel?

I saw a post on another forum of a bloke blaming the powder coating for cracking his wheels on an R1. He appeared convinced his wheels had never taken a hard impact or any other form of abuse and that the heating and cooling caused the cracks.

Anyone have any thoughts or experience?

[DonTZ125]

"ThatKid" could offer more info on the temperatures involved, but I'm gonna say the R1 rider was reality-challenged. Simply heating and cooling the wheel - especially at the rates and limits involved here - will not cause any sort of cracking. It is entirely possible for a wheel with invisible cracks to suddenly display those cracks in glorious detail after that sort of heat cycle.

[Gizzard1533]

Not sure about the heat involved, but weren't the wheels originally powdercoated in the factory? So logic says to me that powder coating wouldn't cause any damage. And wouldn't the powdercoating place soon tell you if the temperatures weren't suitable for an alloy wheel???

[DonTZ125]

I believe the Yamaha practice of 20 years ago was paint; I think it still is.

Not all powdercoat shops are even remotely professional, and even some of the "good" ones may not have the experience to make that sort of judgement call.

[yamaha_george]

I've just booked my back wheel 'n' other bits to get powder coated.

My qustion is, can the heating process of powder coating damage my wheel?

I saw a post on another forum of a bloke blaming the powder coating for cracking his wheels on an R1. He appeared convinced his wheels had never taken a hard impact or any other form of abuse and that the heating and cooling caused the cracks.

Anyone have any thoughts or experience?

Hi,
working from memory Powder coating goes up to 170-210 C degrees in the "curing" stage to achieve flow & finish.
On alloy wheels that have not been subjected to stress this would not even reach alloy annealing temperature (normally 370-410 C degrees ) so heat induced stress is not likely.
Powder coat is subject to damage if not allowed to cool slowly so unless the hot coated wheel was dropped in ice water the chances of sudden chilling cracking the alloy is unlikely since the paint finish would be destroyed also.

there are 2 possibilities the PO does not know the true history of the wheel in question ie it was stressed at some point OR he is playing the painter for a new wheel.

[thatkid]

Most powders have a cure rate of 385° F for 15 minutes. Some are higher and some are lower. The only one that's go a lot higher are hi-temp powders with a cure rate of 450 F for 30 min.

Some ral colors are in the 340 F for 15 minutes. The quick explanation is that a wheel or part gets coated at room temp, and put into an oven that is preheated to the cure temp. Once the part itself gets to curing temp is when the time starts. In most cases a wheel would be in the oven at 385 F for about 35 minutes. This is not enough time to anneal a cast wheel.

The bigger issues would be how the coater prepped then wheel. Some coaters use straight blasting, others chemicals, hell, some even use fire to burn off the old coating. I've seen my share of shady coaters. Don is right in his statement of not all coater are near professionals.

I won't do a powder on a wheel that requires more than 400°F and since most powders can be cured at lower temps for longer times I'll go that route on the wheels as well. Some coaters are in a rush though and will bump the time up for a faster process and more parts per day.

So long as you check out the coater you are using I would say you will be fine. Ask some specific questions that you know the answers to as a quick test to his competence. There are a few things you learn early on as a coater that you don't forget.

But I've coated a lot of wheels and haven't had one come back with an issue.

[yamaha_george]

Tk,
are you quoting Fahrenheit or Celsius degrees of heat.?

I was quoting Celsius which is why my figures seem low compared to yours and I hope my memory is not that off

[thatkid]

Tk,
are you quoting Fahrenheit or Celsius degrees of heat.?

I was quoting Celsius which is why my figures seem low compared to yours and I hope my memory is not that off

Fahrenheit. Only crazy people use Celsius.

[kilika2]

Careful Nate you're awfully close to Canada to say that. I agree though. Haha

Chris.

[Camala_Pillion]

[Fahrenheit. Only crazy people use Celsius.

Could not agree more since we have to follow the french/german dictates of the European Union for all their rubbish rules (like nurse maiding a known terrorist at tax payer expence instead of sending him back to the S***hole he crawled out of "just in case he gets tortured" ) but get none of the good stuff.

[crowe]

Thankyou all for your input. You all have raised a few good points which i'll raise with the "coater" when i see him today.