Recommendations for DFW wheel powder coating shop

[Dante]

What he said.

Before you guys just write off what slowchildmiata is saying, you might want to crack open some engineering text books. He knows what he's talking about, it's his job to.

I wasn't writing him off, but I think in my case the risk is quite small. If I was dealing with a lightweight racing wheel, I wouldn't consider PC given what I've read on the S2k forums. These OEM wheels, OTOH, are pretty durn stout. Besides, I got 8 of them. So what if a couple go kerplunk.

[Robert]

"What he said.

Before you guys just write off what slowchildmiata is saying, you might want to crack open some engineering text books. He knows what he's talking about, it's his job to. "


To cloud the waters even more

http://www.eng-tips.com/viewthread.c...151053&page=10

Without knowing all the variables of the material and temper of the wheel to start and the temp and time the powder coater will use (is he going to crank up the temp for faster thru put) no one can say what the effects will be. I am going to listen to the wheel mfg. over someone on the net I don't know.

[slowchildmiata]

You may need to reread what I wrote because I think you have misunderstood my position and who I was addressing. I said the risk of the PC temperature cycle having a negative effect to cast wheels is minimal to none. My comments so far have been debunking claims of damage to cast wheels and a quote from a salesman named Emilio (I think you took one of my comments as being addressed to you which it also was not). The reason wheel companies say not to is because some prep methods for stripping the paint can damage the wheel and not to mention the fact that it is a process out of their control that they don't want to be liable for.

You have nothing to worry about, which is the position you have taken.

[slowchildmiata]

To cloud the waters even more

http://www.eng-tips.com/viewthread.c...151053&page=10

Without knowing all the variables of the material and temper of the wheel to start and the temp and time the powder coater will use (is he going to crank up the temp for faster thru put) no one can say what the effects will be. I am going to listen to the wheel mfg. over someone on the net I don't know.

Did you even read the whole link? They cite numbers that say it won't hurt.

Powder coating is a CONTROLLED process the guy you quoted doesn't realize that. You can't "crank up" temp with powder coating.

Read CoryPad's post. His numbers are very conservative and still show ok.

[Robert]

Yes I did.

some say it's not a problem others say it could be.

I have seen enough posts about broken wheels after PC ing, more than I linked to and what the mfg say about it, that it's not worth the risk to me.

Sorry about the debate Dante, this will be my last post on the subject. Everyone can make their own choice.

[slowchildmiata]

some say it's not a problem others say it could be.

The conversation evolved into it being ok when they got a few details and actually ran numbers and found a large margin of safety. You quoted a guy that didn't know any details... and his response made sense for what HE knew at that point in conversation(nothing). You are reading it with blinders on.

I too have seen these threads, but I have also NEVER seen ANY proof for cast wheels that the temperature cycle contributed in ANY way (Like I said earlier forged wheels are different and people keep lumping them together). You are citing a guy as subject expert that doesn't even know the difference between accelerated aging and annealing temperatures.

Sorry Dante, I am also done.

[Dante]

LOL Thanks for the clarifications guys. Healthy discussion with relevant facts to make an educated decision that could potentially f up my car, my family, and/or my wallet are appreciated.

[Robert]

Slowchildmiata,

If I read your posts right. I think we agree somewhat that it can cause problems on forged wheels and wheels that are borderline to start with, at least.

[Nails]

Ok I call BS on Emilio.

snip

The only thing powder coating can do is "over-age" aluminum, but if it is PROPERLY heat treated T-6 it would take several hours to overage and get any significant loss in strength. The drop off is quick after that. So... If the wheel was improperly heat treated originally it IS possible for powdercoating to cause significant loss in strength, but the wheel was already bad.

Looks like you agree with Emilio then. He said the stronger the base design of the wheel the less likely it will fail from improper PC technique.
Keyword here is improper. He also said in later posts on that thread how sand or bead blasting a wheel can cause or expand micro fissures in the wheel and that chemical paint removal and wheel prep should be used instead. These are all logical to me and I can see a powder coater being ignorant of these warnings or not vigilant as to the temperature or duration in the kiln.

[slowchildmiata]

Yes 100%. Forged wheels are RUINED by temperature cycle.

If you have a wheel that was T6 and you powder coat it multiple times you can also overage it and make it brittle. T4 would take even more times before it got past T7.

Of all the failures I have seen most are forged wheels (which based on the science/math is a known no no) and the cast ones have root causes else where (ie lug nuts not tight, wheel spacers that prevent centric with hub creating harmonic vibe to failure, chemical stripping of previous coating that chemically anneals the aluminum, or burning off previous coating which also can anneal the aluminum. (last 2 are improper methods of stripping aluminum, but have been done by people who don't know what they are doing)

My main points are: Powder coating does NOT anneal wheels like some claim and if the cast wheel is in good condition and is standard alloy/ heat treat there is almost no chance of damage being done to the wheel by the powder coating heat cycle.

[Nails]

Then what is the best way to strip paint from a wheel if chemicals anneal the wheel?

[Robert]

Sounds good. I am glad we got that clarified.

[slowchildmiata]

Looks like you agree with Emilio then. He said the stronger the base design of the wheel the less likely it will fail from improper PC technique.
Keyword here is improper. He also said in later posts on that thread how sand or bead blasting a wheel can cause or expand micro fissures in the wheel and that chemical paint removal and wheel prep should be used instead. These are all logical to me and I can see a powder coater being ignorant of these warnings or not vigilant as to the temperature or duration in the kiln.

I wouldn't say that (he lumps forgings in with castings and claims PC temps anneal, and that there is conclusive data showing pc is at fault with NO backing and NO scientific method), but of course stronger designs are less likely to have issues. And I also 100% agree you shouldn't believe everything you read on the internet which is why I am trying to educate. I still stand by baking on powder coating does not damage a cast wheel.

Chemical paint removal is higher risk than sand/bead blasting IMO. Sand/bead blasting errodes the surface and stress relieves it. And from what I've seen in other parts/materials the expansion to micro fissures will make them LESS likely to propgate cracks (the errosion smooths them out so has lower stress riser). I would rather have sand/bead than chemical stripping personally. The risk of wrong chemicals being used is too high.

Not all chemicals paint removers will damage the cast aluminum, but there are some...

[Philipio]

I'm going to avoid the argument on temperatures and simply post my recommendation. I know this might look suspicious being my first post but I'm not a spammer. This just happened to be the first thread I opened.

Specialized Performance Coating

This place is top notch and very affordable. I'm very happy with the work. They were EXTREMELY knowledgeable and took the time to not only explain the entire process to me along the way but make sure I was getting exactly what I wanted. I actually discussed the temperature issue with the owner of SPC over the phone for a good amount of time. He was well aware of the potential issues powder coating can have on wheels and said he would take special care to use lower than normal temperatures.

I had four wheels (17x9) powder coated for $275, prices can vary based on size and color.



http://www.spcoating.com/index.html

1107 California Lane #209
Arlington, Texas 76015
(817) 274-1947

[SixAce]

Philipio, thanks for sharing. What did they use to prep? Bead/sand blast?

[slowchildmiata]

Philipio did you go to their place?

Curious because they used to have all their powder coating done through Top Koat... Wonder if they got their own setup now or were still running it through Top Koat.

[Philipio]

Philipio, thanks for sharing. What did they use to prep? Bead/sand blast?

I believe the wheels were sand blasted but I could be wrong. I got my wheels done back in January I think and don't remember all the details unfortunately.

Philipio did you go to their place?

Curious because they used to have all their powder coating done through Top Koat... Wonder if they got their own setup now or were still running it through Top Koat.

Yes I went in the shop when I got my wheels done. From the looks of everything I never once got the impression they didn't do their own powder coating. They never mentioned anything to me about it either.

[slowchildmiata]

Actually looking at the pics I can tell they do their own now based on the coverage...

Based on the coloration of the bare aluminum they were most likely blasted.