Powder coated wheels

I see many bikes for sale with powder coated wheels done by the bike owner.
The bikes look great, but somewhere awhile back I read that you should never powder your aluminum wheels.
It was a tech type article in one of the moto rags I get (can't remember which one). Their take was that the heat required to melt/bake the coating was borderline annealing temp for aluminum.
As a 20 year tool & die maker I have seen the affect of ill-tempered materials fail many times so this scares me and I always keep looking when I see that mod on the wheels or hub.
So my question for the collective is: is there any truth to this? There has to be a metallurgist lurking on here somewhere.

Im not an expert by any means but IIRC most aluminum is annealed at around 700-750 degrees. This is well above the 300-400 degrees that is seen in your average powder coating job. The only thing I can think of that might be a problem is that in the final stages of the hardening process the aluminum is raised to around 350 degrees and allowed to air cool. Im not knowelgable enough on the topic to say 100% for sure, but I dont think that a low temp pc job is going to weaken your wheels.

I would sugest contacting the wheel manufacturer to find out what specific alloy they use and what type of forging, annealing and hardening proccess' they use then doing your research from there,

-Dan

find out how BMW did their forks on the 650 and DON'T do it like that.

I do metal polishing, (click my "linky" in sig line!) since '92, and have dealt with powder coating aluminum parts lots of times, and I have seen with my very own eyes, catastrophic failures of wheels in particular. The problem lies NOT with baking on the powder, but if something goes wrong or you're not happy with the color, and you have to take OFF the powder. The part has to be heated to twice the temp that it took to bake it on, 700 to 800 degrees, thereby rendering something like a wheel.............JUNK. I had a customer have a giant dually wheel turn to dust!!!!!!!!!!!!!
So, if you want to powder coat your wheels, just make sure you're in love with the color you picked out, because if you not, you're either stuck with it or it's "E-bay" time.


Chris "buffy" W.

the way an aluminum foundry i worked at heat treated is to heat it to 700-750 F, quench it at about 190 F, and then "age' it at about 400 F.
The higher temp is just below the melting point, which allows the molecules to go into solution, the quench freezes the crystal structure, and the aging relieves the stresses.

At least that is how I remember it being explained. a metalergist could explain it better.

At my current job we heat treat steel and the overall process is similar. Heat treating is one of those voodoo/black magic things that has MANY variables and a change to any one of them is usually not good.

I don't think powder coating is a high enough temp to change the metalergy.

Which one, the baking on or the baking off?
Since the fiasco with the dually wheel years ago, I've talked about it with a few powder coating people who all told me the same thing...........you DO NOT want to bake off powder on an aluminum piece that your life depends on. Something like an clutch cover, or speedo housing, it doesn't matter much there, no real stress.

Chris

If I wanted to change the color of my wheels, I'd use a tough paint. Powdercoating seems like overkill for a wheel.

No paint can stand up to tire irons. Powder coat is virtually indestructible. Just gotta be sure you know the problem if you decide you don't like it.

I would not burn powdercoat off aluminum, I was talking about baking the powdercoat on.

(it looks like we were posting at the same time earlier)

I've had a lot of success removing powder coat with aircraft stripper is there a reason the pros don't go this route?

Also maybe I've just had a long string of bad luck but I've never been very impressed by the durability of power coating, it is certainly better than paint but far from indestructible. Especially on things which go off road and meet the dirt often not worth the money IMHO.

What about anodizing wheels? Isn't that a chemical process? Can you even do that with cast?

I'd venture to say that whomever has done your coating for you in the past, sucks. When done correctly, it's nearly impossible to get off. I'm working on a SS skid plate right now for a truck that's been coated, tried "aircraft stripper" just to see if it would do anything. Discolored the coating and softened it just a tad. Take it off, NO WAY! I'm in the process of sanding the whole thing bare first, then polishing it.
I had a chrome shop put a CBR600 F4 wheel in the stripper he claimed, "would take ANYTHING off", left it in for four, that's right, FOUR days, and it didn't take it all off. The guy said he never seen anything like it, the stock Honda powder coating, that is.
Anodizing is a horse of a different color, no pun intended. And, yes, you can do castings, but certain alloy's, like my old K100 RS f/peg mounts and such, will come out grey no matter what color you try to do them in. But anodizing is very tough stuff also, as it goes sub-surface. Only problem is, a lot of the colors will fade when exposed to direct sunlight on a regular basis. The once nice orange on the steering damper of my mighty 950, is faded and dismal looking after 5 years. *sigh*

"buffy the dullness slayer"

Isn't there some sort of UV clear-coat type deal you can put over the anodization? Anodized aluminum looks great if it's done right, that's a shame that it degrades so quickly.
As for paint not dealing with tyre irons, personally I like the effect of painted wheels with a polished lip (though the polishing may also disagree with the irons)

While the local companies who coated the rock crawler tube chassis we built at a former job were certainly of a questionable quality, I've never had a bike frame which was powder coated last very long. Then again nothing can stand up to abrasion and being gouged by rocks and other bikes over time. I should also add, the frames I have stripped took a fair amount of scraping and abrasion to completely remove to coating.

Thanks for the reply, your comments about ano'ing different alloys is very interesting indeed, I was aware that it didn't hold up well to constant sunlight but was unsure how much of a role metallurgy played.

Do you work in the fab business?

Well the answers are what I had surmised on my own, just wanted to see if I was wrong.

I'll continue to steer away from wheel mods, especially powder coats. Too bad I was thinking of getting something that's currently in the FM.
It'would probably be safe, but since I have Super Destructive Motorcycle Powers, I'll pass.

Ah, that's where I come in!
I mounted the tires on my MV's Borrani rims with irons...


I was VERY careful, but they came out OK.

Anodizing aluminum is not always such a good idea. It may have no affect at all on a wheel, but I read a few years ago of an Oshkosh Grand Champion helicopter that crashed due to failure of a control rod that was traced back to the drastic reduction in fatigue life anodizing can have on aluminum.

Ken

You better do all the "Big 4" sport bike riders a gigantic favor and alert Honda, Yamaha, Suzuki, & Kawasaki of this glaring mistake they are making by anodizing their frames, thereby endangering a large chunk of their customer base. Gawd, you would think they would do a quick interweb search like you did before they go and do something like anodizing the frame. Better let Ohlins know while you're at it, those inverted fork "uppers" are an accident just waiting to happen.



Chris

You can't buy a structural component on a bicycle which hasn't been anodized. I have a hard time believing this.

Without getting into the metallurgy of it all, several centuries ago when I worked for Ford manufacturing cast aluminium wheels (cast, machined & powder coated) we only had two additional passes through the powder coating ovens to repair any faults before the wheel was scrapped. Aluminium age hardens naturally and the additional thermal blast from the powder coating curing ovens accelerates the process, so three passes total was all we would allow.
As the only way to soften or restore the original metallurgy is to heat and quench the wheel they are unreworkable, as that process distorts the wheel and you can't re-machine it.


Who knows how many passes through the oven your alloy wheel has had?

Two pack epoxy for me on any aluminium component.

Wouldn't powder coating add a significant amount of weight to the single most important part to minimize the weight on? Seems like a farkle for posers in my book.