Powdercoat wheels = Weak rim strength?

Does powder coat = a weak rim??

Apparently you need to be in charge of the whole powder-coating process from start to finish to make sure it's done right.

Supposedly high temperature over 200° can anneal & weaken some aluminum/alloy rims. And powder coats are usually baked on at 350 to 450° ... though there might be low temp powder coats out there.

But the shop could tell you one temp and bake it at another.

Also, some say sandblasting ruins the rims and causes microscopic cracks. Unless they blast with walnuts...apparently walnuts are safer.

Has anyone successfully ran powder-coated cast (low pressure cast) rims with no problems and no rim cracking, etc.?

Did they use walnut blasting and did they use low temp/bake powder coat ?

and were they OEM or aftermarket rims?

Just found out the local place doesn't use walnuts and they cook at 375°. At least it's not 450°. Heard 450° will completly destroy an alloy wheel.

And can't get bi-color rims or the machine flanged look. They only do one(1) color so need to make sure it's a color goes well with machine gray.
 
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Yes, by all means encourage the blatantly incorrect information that was shared, and then call me out for bringing that to light and telling others to do their own research rather than use this shared “information”. Someone in the thread did say the below…. Oh wait that was the guy you’re encouraging….

You moderators here run one of the worst forums going, with a dreadful level of activity. I’ll move on and let you pat everyone on the back for posting incorrect information and using the forum as their personal blog to blather on and on to themselves. I’m sure you’ll remove this post soon enough, but thought I’d write it anyone in hopes you might improve the forum for the very few active posters.
Dude:

What's with the personal attacks ??

Three manufacturer's have responded , two(2) large companies have said that powder-coating their factory painted wheels will ALTER/WEAKEN the wheel structure.

One of the smaller one that powder-coats their wheels has AVOIDED the question and won't provide the temperature they powder-coat nor provide assurances that powder-coating is safe.

Aside from the point that my thread was concerning powder-coating by a third party, not by the manufacturer.

On Post #8 , you made the claim that :
"For others reading the thread, no, the temperatures and length of time at those temperatures used in the powder coating process will not impact the structural integrity of an aluminum alloy wheel."

You have yet to provide one shred of proof, website, documentation, etc. that powder-coating at high temperatures(325 F and higher) will not alter, weaken or damage a wheel/rim.

Instead you continue on and on with character assassination.

Which seems to be a common trend in your other posts as well.
You constantly question others and demand proof without providing any of your own.

It is a free country and you are free to do as you wish but I am kindly asking you that if you don't like my threads, please don't read or post on them.

Thank you.
 
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Yes, by all means encourage the blatantly incorrect information that was shared, and then call me out for bringing that to light and telling others to do their own research rather than use this shared “information”. Someone in the thread did say the below…. Oh wait that was the guy you’re encouraging….

You moderators here run one of the worst forums going, with a dreadful level of activity. I’ll move on and let you pat everyone on the back for posting incorrect information and using the forum as their personal blog to blather on and on to themselves. I’m sure you’ll remove this post soon enough, but thought I’d write it anyone in hopes you might improve the forum for the very few active posters.
He isn't incorrect. If manufacturers are indeed using cast A356-T6, 2 minutes at 400 degrees is enough to "soften" the wheel. That's precisely what specialty wheel repairs shops do to straighten out bent wheels. You then have to re-age it appropriately at a lower temperature for a period of time to achieve the required Vickers Hardness. This is something like 10-15 hours at 320°F.

Powder coating typically bakes for 20 minutes, so something like 375°F will still take somewhere around 2-3 hours to "soften" the wheel. The main issue is fatigue strength when you change the temper. These wheels are manufactured, heat treated and tempered under very controlled conditions.

First article inspections, tensile coupons, fatigue compouns, etc. are all taken and analyzed throughout this very particular process to ensure the wheel will operate as desired for as long as desired.

Can you probably get away with powder coating these wheels? Sure

Will it affect the wheel temper? Absolutely.

Will they fail catastrophically? Not likely, but they very well may develops cracks earlier than expected depending on the bake time and temperature slightly altering the wheel temper.

Why wont the manufacturer sign off on this? Because the forging/casting house follows specific standards defining heat treat and aging processes. Any deviation from those requires new coupon testing and first article inspection sacrificial testing to generate new material properties data and S-N curves for fatigue lifing.

I'm a pretty ornery guy, but you come off as straight up rude.
 
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mazda ca

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Yes, by all means encourage the blatantly incorrect information that was shared, and then call me out for bringing that to light and telling others to do their own research rather than use this shared “information”. Someone in the thread did say the below…. Oh wait that was the guy you’re encouraging….

You moderators here run one of the worst forums going, with a dreadful level of activity. I’ll move on and let you pat everyone on the back for posting incorrect information and using the forum as their personal blog to blather on and on to themselves. I’m sure you’ll remove this post soon enough, but thought I’d write it anyone in hopes you might improve the forum for the very few active posters.
Just stop. Or just leave already.
 
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Antoine

Administrator
Side note: Zoom21 has requested his account be deleted and it is now deleted.

I want to commend everyone else here for keeping calm and responding in a civil way. Being confrontational, rude, overly critical etc does not encourage civil discourse and it’s also against site rules. Such behavior may lead to warnings and or having your account permanently banned.

Again, it really speaks volumes about the fantastic Community we have here that everyone else remained civil, well done! 👍

Now let’s keep this thread calm in addition to on topic, thanks!
 
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sm1ke

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So, I looked into one of the powdercoating businesses local to me. They powdercoat everything from park benches to engine parts and wheels. On their website, they posted their process, which is to bake the part for 10 mins @ 400f, then remove it to cool. When cool, they say it's ready for pickup. I don't know if they change their process when they powdercoat different materials (steel, aluminum, etc.).

Now, this company has done quite a few wheels for local enthusiasts, and it looks like they have a 5* rating on Google with 44 total reviews. Just from this one example, it would seem that the effect of the powdercoating process from this shop isn't significant enough for failures to occur - but again, this is just one example with a very small sample size.

I'm thinking about sending my wheels to this shop sometime in the next couple of years to get a minor bend repaired and to get the wheels powdercoated. The difference between my case and yours @Jack Rabbit is that I am running tires that have a ratio of 35, compared to your tires, which will likely have a much higher ratio (and thus a much taller sidewall). IMO, if the wheel/rim is indeed weakened to a slight degree, a taller sidewall should provide enough cushion to protect against pothole or curb damage. With that said, I think I'm still going to get my wheels powdercoated because as I mentioned earlier in the post, there are a lot of locals who have had their wheels powdercoated by this company and who run them on rubberband tires without issue (so far, at least).

YMMV, but in my opinion, I think you'll be fine with powdercoating, especially with the taller sidewalls.
 
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So, I looked into one of the powdercoating businesses local to me. They powdercoat everything from park benches to engine parts and wheels. On their website, they posted their process, which is to bake the part for 10 mins @ 400f, then remove it to cool. When cool, they say it's ready for pickup. I don't know if they change their process when they powdercoat different materials (steel, aluminum, etc.).

Now, this company has done quite a few wheels for local enthusiasts, and it looks like they have a 5* rating on Google with 44 total reviews. Just from this one example, it would seem that the effect of the powdercoating process from this shop isn't significant enough for failures to occur - but again, this is just one example with a very small sample size.

I'm thinking about sending my wheels to this shop sometime in the next couple of years to get a minor bend repaired and to get the wheels powdercoated. The difference between my case and yours @Jack Rabbit is that I am running tires that have a ratio of 35, compared to your tires, which will likely have a much higher ratio (and thus a much taller sidewall). IMO, if the wheel/rim is indeed weakened to a slight degree, a taller sidewall should provide enough cushion to protect against pothole or curb damage. With that said, I think I'm still going to get my wheels powdercoated because as I mentioned earlier in the post, there are a lot of locals who have had their wheels powdercoated by this company and who run them on rubberband tires without issue (so far, at least).

YMMV, but in my opinion, I think you'll be fine with powdercoating, especially with the taller sidewalls.
Thanks Sm1ke.

I think the issue im having is the places around here bake at 375 for an one or even two hours. One local even bakes at 425. Just a little too hot or too long.
And they don't seem to be willing to bake lower or shorter. Their ovens must not have thermostats...although I think they do. Or there staff isn't conveying the right information to me..regardless it's bad business practice.

Wish your powder-coater was close.
May have to look around some more to find a powder-coater that's flexible. Or just get painted.

Want to use the wheels because theyr'e Mazda factory 16 incher's with the correct et45 but don't want to spend money to ruin them. At that point could have bought the new aftermarket rims with et40.
 
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sm1ke

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Thanks Sm1ke.

I think the issue im having is the places around here bake at 375 for an one or even two hours. One local even bakes at 425. Just a little too hot or too long.
And they don't seem to be willing to bake lower or shorter. Their ovens must not have thermostats...although I think they do.

Wish your powder-coater was close.
May have to look around some more to find a powder-coater that's flexible. Or just get painted.

Want to use the wheels because theyr'e Mazda factory 16 incher's with the correct et45 but don't want to spend money to ruin them. At that point could have bought the new aftermarket rims with et40.

Honestly, with your experience with DIY painting/prepping wheels, I think having the wheels blasted and painting them yourself would be a happy middle ground to settle on. You'd get the look you're after with less elbow grease than having to sand the wheels down yourself. And you'd get the peace of mind from not having to bake the wheels and risk a weaker structure.

Do you have any local enthusiast clubs? Maybe they could recommend a shop/powdercoater that does good work?
 
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azcx5

2021 GT-R SRCM with Parchment
FWIW, I had the alloy wheels on one of my Porches powder coated about 8 years ago. Very low profile tires, and driven agressively on lots of twistie's without any issues. Granted not off roading, but enough potholes and rough roads around here and the wheels never cracked or bent. Porsche factory wheels so very high quality. Enough people powder coat their wheels that one could presume it is safe.
 
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