Hey, I've seen a few threads where people say that powdercoating forged wheels is detrimental to their structural integrity. I just have one simple question about this that i didn't see brought up. If running a wheel through a 400 degree oven makes them fall apart, what about any time you touch your brakes? the wheel is in direct contact with that rotor. Wouldn't it be risky for auto manufacturers to put out a product that potentially does such a thing? Maybe your brakes don't get that hot on the street, what about when they're glowing red at the track? Thats over 1000 degrees. Does anybody have anything to say about this? The whole idea seems perposterous.

 

Just because the brakes get that hot doesnt mean its affecting the wheel in the same way that baking it over a period of time at XXX degrees does. 2 different things.

Think of it like this, when you go outside on a 100 degree day youre not standing there getting burned alive, but if you put your finger on a pot on the stove thats 100 degrees, chances are youll be getting burned pretty badly if you hold your finger there.

Poor analogy? Perhaps lol but thats the gist of it.

 

As long as the powdercoater knows what they are doing, you will be fine. Its all about the curing process.

 

Actually, your analogy fights for my point. If youre cooking your brakes at the track, the wheel is held in DIRECT CONTACT with the brake rotor for extended periods of time (like putting your finger on a stove). But when you powdercoat the wheel, youre putting it into a room with high temp. air (like walking outside in the desert). And powdercaoting only heats it to 400 degrees. Glowing rotors require excess of 1000* F. don't you think that the wheel would recieve heat transfer? That's really effin hot. Idk, I just fail to see how powdercoating could heat a wheel more than tracking a car. Unless somebody went to the track and pulled over by slamming the brakes, hopped out of the car and measured the wheel's temperature. Does anybody see my point?

 

The wheel's contact point is not the rotor, it's the hat. While the rotor may be a sizzling 1,000 deg F, the hat is *significantly* cooler as it is not directly exposed to friction. Iron has pretty good specific heat characteristics (lots of energy req'd to change its temperature for a given mass of iron) and I'm sure you'd see temperatures *well* below 1,000 deg F on the hat, even when the rotors are that hot.

Furthermore, the actual points of contact between the hat and the wheel are pretty small; take your wheel off and look for the pattern of "clean" area on the hat. There's a very limited amount of heat being transferred because of the limited temperature of the hat in addition to the limited contact surface area between the hat and the wheel. Also remember there's a big air gap (from a heat transfer perspective) between the rotor and the wheel - this gap insulates the wheel from the heat of the rotor, too.

Powdercoating, on the other hand, sticks the entire wheel into an oven, where it is uniformly brought up to some high temperature (I don't know exactly what this temperature is but you wrote 400 deg F, so we'll use that assumption). The problem with re-heating is that you may change the properties of the metal.

Without understanding what kind of wheels you're powdercoating, whether they were cast, forged, and how they were heat treated in their manufacturing process, you may irrevocably alter the metal's properties for the worse. This could cause unrelieved stresses to build up in the wheel and a subsequent, unpredictable, and catastrophic failure of structural integrity.

While 400 deg F doesn't sound very high, it's pretty much guaranteed to be higher than the temperatures that your wheel is ever going to see even under the most severe braking. Unless specifically recommended and/or OK'd by the manufacturer, painting is the safer way to change a wheel's appearance when compared with powdercoating.