Corvette C5 Magnesium Wheel Refinish??
11-12-2008, 03:04 AM
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Corvette C5 Magnesium Wheel Refinish?? I recently got my hands on a set of rare C5 Corvette Magnesium Wheels. They are Corvette RPO Code N73 made by Speedline in Italy I think. Rear 18X9.5" and Front 17X8.5". They were used on a road track car and cosmetically pretty rough when I picked em up.
Alright...I tried media blasting them and painting them (base/clear) and the moisture got underneath the paitn and it bubbled. They were originally powder coated that gold color from GM. Now if you have seen these wheels before you know there are pressed-in steel rings in each lug hole for strength. These rings are held in with some type of adehsive.
Who knows:
1. These HAVE to be powdercoated?
2. You can't heat them passed 200 deg F. or they warp/weaken?
3. Need to remove steel lug rings before powder, then reinstall after?
4. Special adhesive needed for re-ring?
Anyone who has dealt with these wheels or any magnesium wheel please chime in. Any help is appreciated.
Alright...I tried media blasting them and painting them (base/clear) and the moisture got underneath the paitn and it bubbled. They were originally powder coated that gold color from GM. Now if you have seen these wheels before you know there are pressed-in steel rings in each lug hole for strength. These rings are held in with some type of adehsive.
Who knows:
1. These HAVE to be powdercoated?
2. You can't heat them passed 200 deg F. or they warp/weaken?
3. Need to remove steel lug rings before powder, then reinstall after?
4. Special adhesive needed for re-ring?
Anyone who has dealt with these wheels or any magnesium wheel please chime in. Any help is appreciated.
11-12-2008, 05:00 PM
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Do you know the specific process that was used, temp used to bake? I have conflicting advice, so to heat or not to heat? Is there a cold powdercoat? i just don't see how that adhesive in the lug holes would survive 400 deg. Magnesium is flammable?
What company did you have refinish your wheels?
11-12-2008, 08:29 PM
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Very.. I take it you've never seen a magnesium fire before? Search for "Magnesium Fire" on youtube and you'll find some interesting/entertaining stuff. Best part, is when it's on fire and you put water on it, it actually adds to the fire rather than putting it out.
You should be fine powder coating them though.
You should be fine powder coating them though.
11-12-2008, 08:52 PM
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yes magnesium is flammable but these wheels have a different chemical mixed in them or is not 100% magnesium would car manufactures really install wheels that are flammable in a car accident?
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11-12-2008, 09:01 PM
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I'm hoping not.. especially being made of magnesium that would be an accident waiting to happen. I'm sure they've done something to the extent to help reduce the risk of the wheels burning.
11-16-2008, 02:58 PM
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12-09-2008, 01:59 PM
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Who did you use to do the refinishing?
Nice wheels if I can get them freshened up, or if any of you guys want them I would let them go cheap (or trade).
Bob
12-09-2008, 09:38 PM
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do not media blast magnesium wheels. we had a rare alfa romaeo at my work that was made of 100% aluminum and was all rivited together. anyways the owner send the wheels out and had them media blasted and it pitted the hell out of them. i would recommend soda blasting them.
12-16-2008, 11:46 AM
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Check with a Chevy dealer's body shop, they know what to do with these to refinish properly. It's damned expensive and most anyone who knows how to do this right won't be much cheaper. If memory serves (it's been 3 or 4 years), it used to be 300 a wheel just to get one refinished. There is a thread with wheel weights (search it up) but the magnesium babies are about 2 pounds lighter than the Z06 rims, which are very light in the their own right. It's a big difference if you autocross or have a comfort-sensitive hiney. 
03-07-2009, 02:42 PM
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Powder coating magnesium wheel, the truth After much research with magnesium metallurgists and magnesium companies, here is what I have come up with. There is absolutely no reason you cant powdercoat magnesium, iit is done quite regularly. Heres some numbers for you that are sceptical. Magnesium has an ignition temp of 1107F degrees and a melting point of 1202F degrees, no where near the temps we reach P/Cing (400F)or even outgassing them at 500f. Most magnesium wheels are made from an alloy called AZ91, my motorcycle wheels are AZ91C and most mag wheels today are of an alloy of AZ91E, the latter having fewer impurities in the alloy than my 35 year old wheels. Though heating to the temps required to powdercoat them does soften them, when they return to room temp they are returned to the SAME harness they were before. If your wheel was bent and then straightened ,this heating will actually help by bringing it back to its original hardness. Most of the wheels were made of an alloy that was not originally heat treated, so you are not removing any heat treat p/cing them. Blasting should not pit magnesium anymore than aluminum, the pitting on your alfa wheels was probably hidden under the old coat and revealed after blasting. But heres the thing with blasting magnesium, it will competely remove the corrosion resistant layer built into the wheel, so if after powdercoating, the surface were to get a scratch or gouge down to bare metal, corrosion happens at a rapid pace. I was told that on show pieces this should not be a problem unless scratched or chipped and exposed to the elements. The simple solution to this problem is to have the wheels anodized to give it a profile for the powder or paint to adhere to, or after blasting to run the wheels through another pickling process to bring the corrosion resistance back. Lots of horror stories out there of wheel failures from powdercoating, I dare ANYONE to show me one example with data to show the p/c caused the failure of a magnesium wheel. I can p/c your wheels for a whole lot less than $300 each. Also when it comes to media blasting, if you send it to your local sandblaster, they dont understand what the part they are blasting is for or how much care should be taken on it. To them time is money, so turn the blaster up full and blast away at 10,000psi (exagerated), so you should have them blasted at a much lower pressure, takes longer but doesnt do the damage
Last edited by o1racing03@aol.com; 03-07-2009 at 02:48 PM.
03-07-2009, 03:50 PM
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Here is a set GMMG done for a 1 of 1 2002 Collector Edition Formula
http://www.highperformancepontiac.co...ion/index.html
http://www.highperformancepontiac.co...ion/index.html
