I'm looking at having my aluminum wheels powder coated black this summer once the trans is built. I was reading up on a corvette forum (the worlds pickiest drivers) and they were saying that powdercoating aluminum is bad on the wheels. Something about at the temps needed for powdercoating it weakens the aluminum and can cause the wheel to fail. Now granted these wheels were used for racing and stuff but I do plan on abusing my truck down the 1/4 a bunch and I daily drive this thing so they need to last. Just thought I'd get an answer from people who are a little more normal and down to earth.

 

Heating alluminum will aneal it(soften) and make it bend much easyer and it happens at a farely low heat. hate to hit a pot hole and tweek the wheels or haul a load and squish them out of round

how about epoxy paint? my .02

 

Call Mickey Thompson and see if they can stand 400F for 20 minutes? If they can, let me know since I wanna try it.

brnadon.

 

I doubt M/T wants to hear from me. I'm currently a big thorn in their side.

 

Hmmm... know what type of aluminum it is? Maybe you can disguise your voice to call in?

bnraond.

 

No clue but I'll see what I can find out.

 

400 degrees is below the anneal temperature of Aluminum and its alloys. The wheel will most definitely lose strength while at temp (~60% at 400 deg F), but it should be fine once it is cooled. Most charts I use are for sheeting and not huge castings like a wheel, but it should be fine. I seriously doubt the core of the wheel would reach 400 in only 20 mins anyway.

Edit: Found some info on large castings, and it is a fair amount different than sheeting/bar info. There is a definite possibility of losing some strength at that temp... how much depends on the material.

 

Agreed, it would most likely take hours - not minutes to completely heat that cast aluminum rim to the core at 400*. When we heat treat aluminum, it is usually for 8 hours at a time to ensure even and consistent core temperatures. Besides, some aluminum castings won't even accept any form of heat treating and will remain unchanged after heating....I don't have any idea what the alloy of these wheels are either. We powdercoat various aluminum alloys daily and have done frequent strength testing before and after powdercoating with absolutely no change in the temper, tensile and ultimate strengths......as banshee mentioned, 20 minutes will simply not be long enough to noticably affect the temper of the mass of something like an aluminum wheel.

 

So basic consensus is that the metal is not going to get hot enough long enough to damage it. I did a little more research on this and read up that the powdercoating dude can lower the temperature of the oven and just bake the wheel longer that way it doesn't get to the critical 400* some odd degrees. What do yall think about that? I'm tired of having to wet sand these suckers and polish them every week and I'm bored with the whole polished aluminum thing so I'm going to do some tweaking. Thanks yall.

 

Powder coating at lower temperatures is not recommended, I find durability best on the powders I use to be at around 375 for about 14 to 18 minutes depending on the colour. AT Lower temperatures the powder won't fully cure and harden.

Rather than using an oven bake process you may want to consider a infrared heating process, it tends to heat just the powder and you do one side at a time so you don't end up heating the whole wheel.

 

Interesting. I'm just doing a nice gloss black. Nothing fancy. Thanks for the help yall.

 

The cost of the labour is most of the cost, the powder costs nothing, the powder to do 4 wheels would be like 20 bucks or so, why not do something fancy with powder.

 

Are you sure you dont wanna paint them blue? jk

If you do make sure the powder coat is sun resistant. there are two or more types of paint.

one of them, we painted our homemade bumper, lasted only a few months, and then faded. later we painted them with outside lasting paint. still looks great.

 

Big Blue do they have tobe powder coated? I work for tredegar industries (bonnell) one of the largest suppliers and manufactures of aluminum in the U.S. and I assure you that thier are other ways to paint aluminum. If have the box they come in or can find anything on them their should be a number like 6063 T5 or T6, 6061 T6, 6005 T6, something like that. If you can find them we could tell you more about it.

 

http://www.bonlalum.com/Login/index.jsp here is some reading about the company I work for, It tells about the ways we anodize and paint and other processes that we do.