Well I'm not a chemical engineer mate, I've got no idea what kind of metals are used to make those rims, what the melting point is etc. Even if the melting point was a lot higher than 250C it doesn’t mean that the chemical bonds in those metals won't be weakened. I'm not sure if you'd be able to get that kind of information even from the manufacturer himself. In my opinion 250C is safe enough but I am just guessing...is it worth risking your life??

I've done a lot of car related powdercoating for my mates but mainly intercooler piping and the like. Never touched rims b4.

Makes sense I guess

__________________
TD06 - Oink.

perth powdercoaters in belmont... FTW

got my sti rims powdercoated Charcoal Pearl Metalic the other week and they came out bombeddd!!!... only $250 speak to Tim a.k.a SUBASTYLN

__________________
JAY's (Pig Sti)

Was it $250 for all four rims Jay??

__________________
VE SS Blk on Blk

i got quoted $250 to powder coat my rims on the STi, not doing it now, coz I want new ones

Dan, what are u doing to F6 already?

Oh ok that sounds cheap, cheers...

__________________
VE SS Blk on Blk

yer mate all 4 rims for $250 specail price cause where through perth rex.. yippi.

__________________
JAY's (Pig Sti)

nice....yeah i went down there yesterday or the day before.... and it wasnt open..... might give it a go another day.....
reckon they do matt black??....i want matt black... hahaha

__________________
MY00 Impreza WRX
[LTDGC8]

its not ONLY boyz who drive nice cars!!!!

Go to Tim @ Perth Powdercoaters. He did my MY00 rims, price was spot on, finish was stunning and still is (minus bulk brake dust). I went a colour that came in matt only, so he clear-coated them for not much extra, and the finish is very tough and easy to clean.
Had some technical info on hand:
Melting point of aluminium is 660C.
Melting point of Al-Cu alloys as low as 520C
Melting point of Al-Si alloys as low as 570C.
The majority of 'mag' wheels are made of aluminium alloys, but I have no idea what alloys are the most common

The book I have here mentions for a stress relieving heat treatment of an aluminium alloy, soak times "can be as short as 15min". A rough graph indicates stress relieving to occur between 190-280C, with the lower end requiring a longer heat soak of up to an hour. (This is all eye-balled from a rough chart btw, so don't take it too seriously, the values could be quite far off!)

In my opinion, if any stress relieving occurs for such a short time at that temp, this is not a massive concern, it may even be of benefit? If the alloy was hardened I would be more concerned. For example if I kerb a rim I would rather it buckle than crack, especially if I don't spot hairline cracks and continue driving on it!

your brakes will hit upwards of 600 degrees doing a lap of wanneroo

__________________
MY93 Impreza GX 1.8L, 0hp, 0nm