Refinishing/Restoring/Repainting Magnesium Wheels

[tomnj]

I picked up some Cromodora's (like the ones below, not these exact wheels) for my 850 last summer and refinished (spray painted) them silver. I don't really like the way they look, I feel the silver was too bright.

To me, magnesium wheels should be more like a grey/silver or even a silver with some yellowish tint to it. I remember the silver spray paint I used to use in the 1980's used to be more yellowish than today's silver spray paint, which is too bright for my taste.

Is there a proper way to "refinish" a magnesium wheel or a spray color that matches the original look (or magnesium look) best? Dupli-Color Silver Wheel paint is too bright and their metallic grey color is too dark IMO. Maybe a light sanding and clearcoat would be best?

 

[motoTrooper]

Eastwood sells a wheel paint called "Argent Silver" also it has only 50-60% gloss in it. It's supposed to be a warmer tone and more period correct for old vehicles. Here is the link:

https://www.eastwood.com/ew-rally-wheel-argent-silver-paint-areos-12-oz.html

Hope it helps!
-Christopher

 

[twincam69]

I've used Rustoleum metallic matte nickel 7277830 in the past. I like the shade on magnesium wheels and it's not too glossy.

 

[Mark]

I followed this write up when I did mine.

https://stevekouracos.com/restoration/tips-and-tricks/aluminum-magnesium-wheel-restoration/

Media blasted:

Acid:

Alodine:

Drying:

Finished:

I picked up some Cromodora's (like the ones below, not these exact wheels) for my 850 last summer and refinished (spray painted) them silver. I don't really like the way they look, I feel the silver was too bright.

To me, magnesium wheels should be more like a grey/silver or even a silver with some yellowish tint to it. I remember the silver spray paint I used to use in the 1980's used to be more yellowish than today's silver spray paint, which is too bright for my taste.

Is there a proper way to "refinish" a magnesium wheel or a spray color that matches the original look (or magnesium look) best? Dupli-Color Silver Wheel paint is too bright and their metallic grey color is too dark IMO. Maybe a light sanding and clearcoat would be best?


View attachment 21486 View attachment 21487

 

[Dr.Jeff]

Mark, those came out great. And that's quite a process to get there. I'm curious, in your picture of them after media blasting they appear to have a green tint (or is that an artifact of the camera/photo) and glossy (or is that lighting). I would have imagined a blasted magnesium wheel would be a very dull grey looking.

I suppose it might depend on the goal for the car overall; local shows, track, concours, driver, stock restoration, etc..
I've always loved the look of real magnesium wheels in their natural finish.
One thought might be to glass bead blast them, then seal it with a mat clear. That should give the look of raw magnesium.
As far as paint colors, I tried some "magnesium" spray paint from Seymour (the originator of spray can paint and the largest maker in the world). It turned out a lot darker than I expected. More of a dark grey than silver. Like you, I'd like to find something in between. The "argent silver" Christopher referred to looks great. I believe it's the same color as original BMW factory alloys were in the 80's. However it might be a little too 'silver' though...more for aluminum wheels than magnesium? But it is a nice low gloss finish.

 

[twincam69]

I found a couple of pics when I refinished mine. The final finish is the Rustoleum Matte Nickel..

 

[Mark]

Not sure about the green tint, but the wheels were freshly wetted down it that particular photo.

Bare magnesium oxidizes badly, so I wouldn’t recommend leaving them bare.

Mark, those came out great. And that's quite a process to get there. I'm curious, in your picture of them after media blasting they appear to have a green tint (or is that an artifact of the camera/photo) and glossy (or is that lighting). I would have imagined a blasted magnesium wheel would be a very dull grey looking.

I suppose it might depend on the goal for the car overall; local shows, track, concours, driver, stock restoration, etc..
I've always loved the look of real magnesium wheels in their natural finish.
One thought might be to glass bead blast them, then seal it with a mat clear. That should give the look of raw magnesium.
As far as paint colors, I tried some "magnesium" spray paint from Seymour (the originator of spray can paint and the largest maker in the world). It turned out a lot darker than I expected. More of a dark grey than silver. Like you, I'd like to find something in between. The "argent silver" Christopher referred to looks great. I believe it's the same color as original BMW factory alloys were in the 80's. However it might be a little too 'silver' though...more for aluminum wheels than magnesium? But it is a nice low gloss finish.

 

[twincam69]

I used zinc chromate (the green primer in the pic) on magnesium before. I know some say no, but when you look beneath the factory finish that's what seems to have been used. It's been a couple of years and they still look good. Just my experience...

 

[tomnj]

Mark, those wheels look amazing and I like the color, like a light grey.

TC69, the Rustoleum looks good, I just ordered a can and will test it out. In your picture notice the original wheel finish was almost like a platinum color, with a yellowish tint? I'm sure some of that is just age, but that's the way silver paint used to look in the 80's. Todays silver is too bright and colorless (no yellow tint) to reproduce that original finish.

 

[myredracer]

I followed this write up when I did mine.

https://stevekouracos.com/restoration/tips-and-tricks/aluminum-magnesium-wheel-restoration/

I like those! Nice job Mark.

You really have to know what you're doing if refinishing magnesium wheels. The steve kouracas website is the best I've seen. They can be a real problem if they have corroded and have the white powder on them and even to the point of not salvageable. Inspect carefully everywhere for corrosion and don't ignore it and paint over it. Magnesium is also porous and can cause tires to deflate and if moisture migrates through the metal, you've got an irreparable wheel. If they happen to be damaged and needed welding, you need to find a specialist that can do magnesium. I had an aircraft welder repair an 850 racer cromodora wheel once that had a chunk missing off the rim then had a wheel shop refinish the set. You do NOT want to curb real mag wheels. There's a reason cars have aluminum wheels nowadays.

If all of the original finish is 100% good, I would wash & clean the wheels, scuff up the paint with the appropriate grit scotchbrite pad, clean with W&G remover, spray epoxy primer on them and then use the paint of your choice. If using epoxy, it has a recoat window of 2-7 days where you can topcoat it. If you miss the window, you need to scuff all the paint again first.

You might try an auto body paint supply shop and see what they have for doing wheels. You might inquire at a wheel restoration shop and see if they can advise on paint.

I have a set of CD30s. Two of them are badly corroded and beyond repairing. I also have a set of magnesium cromodoras like tomj. I have a media blast cabinet large enough for a wheel and can refinish them from scratch. Taking rims to a wheel restoration shop is definitely an expensive way to go.