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Full Version: Painting Magnesium Rims. . My adventure
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toolguy
I just went thru a long process of figuring out how to paint my Mag / Gasburner rims. . Initially I was going to powder paint them as my nephew has a powder business and it would be no cost to me. . . After some in depth research, we found some potentially big issues with baking / powdering mag rims. .

1st issue was excessive gassing during the baking period. . seems magnesium has a lot of porosity and can produce bubbling in the powder even if they are pre-heated and powdered hot. .

2nd issue was about metal deterioration from high baking temps. . that turned out to be less of an issue if you bake them under 400 degrees but there is lots of internet chat about the metal losing its strength with higher temps. .

3rd issue was what to do if I needed to remove the powder in the future. . powder is very hard to remove with blasting, the usually shop practice my nephews business uses to remove powder is to bake at 600 and burn it off which would destroy the magnesium. . or dip them in a chemical stripper, which I didn't think would be any too positive either. .

4th issue. . Apparently magnesium absorbs and reacts badly to humidity and the atmosphere. . that is what causes it to turn blackish and produce a whitish corrosion on the surface. . This can end up lifting any powder or paint applied over a contaminated surface. . therefore it needs to be painted or somehow have the surface sealed directly after blasting. .

The end of the story was that I bead blasted the factory finish completely off, which had some very hard and durable primer coats. . The base coat was a yellow coat and then a blue secondary coat over that. . took about an hour a wheel to get all the multiple nooks and crevices stripped bare of the factory coating. .

Then each wheel was promptly primed in PPG DP40 metal etching primer. Let these dry overnight. The next morning I shot them with color correct silver single stage Urethane with flattener to achieve the semi gloss surface, Three full coats with 30 minutes between coats.
Total investment for the PPG paint and primer, with catalyst, reducer and flatener came to $320, plus the 5 hours to strip the rims and another half day to paint them.
Probably the hardest part was coming up with a silver paint that didn't have a 'metallic' sparkling appearance. Ended up having one mixed with the smallest flakes available.

I had gone to a good quality paint and body shop before all this when i was in the planning stage and asked for an estimate for them to blast and paint. . Their 'Friend' discount price was $1500 total, priced at $100 per rim to blast and $200 a rim to paint for a set of 5 with center caps. .

If nothing else it's a good sense of accomplishment and the saved money was the bonus. .
sb914
They look great! Nice job
ConeDodger
The 5th issue is they are Gas Burners! They're worth a fortune and if you screwed them up??? sad.gif They look good though! Congrats!
somd914
Nice job beerchug.gif
veekry9
Do you have a pix of the backs?I assume they were done the same.
Color correct,a number of the mix?
Nicely done,the reason I ask.
We were always cleaning post blasting with 'Gunk brand brake cleaner',the compressor lube present in most blaster's supply a contaminant.
Cairo94507
Wow- those look terrific. And, I really appreciate that you posted about your experience and research.

Once my car is done and back in my garage, I plan to find a set of gas burners for it as I love the Six with gas burners and will most likely have to refinish them. Your wheels look perfect. smilie_pokal.gif smilie_pokal.gif smilie_pokal.gif
76-914
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Mueller
Looks great...years ago I had a set of modular Ronal Racing wheels with the magnesium centers. When I 1st got them I stripped them and polished 'em up. They looked great for a while. Needless to say I ended up painting them not too long afterwards.

DCJosh
How do you know they are magnesium and not aluminum? I have not seen anything that says that they are magnesium. confused24.gif I'm genuinely interested. Thanks.
Johny Blackstain
My favorite factory 914 rim by far. They look great drooley.gif

All Mahle 5 lug rims were made out of magnesium, not aluminum. If they're made out of anything else they're not genuine Mahle's. Four lug Mahle's were made out of aluminum. Somebody out there makes 5 lug replicas & they are not made out of magnesium.

If I ever did a 5 lug conversion to an LE I would choose 5 lug Mahle's only. Expensive yes, but somehow seems proper to me.
mepstein
QUOTE(DCJosh @ Apr 4 2016, 10:33 PM) *

How do you know they are magnesium and not aluminum? I have not seen anything that says that they are magnesium. confused24.gif I'm genuinely interested. Thanks.

They are mag. I've owned 2 sets. Need to be painted or they corrode. Very fragile wheels. Not daily drivers. Mine were all right around 10.2lbs each.
DCJosh
QUOTE(Johny Blackstain @ Apr 4 2016, 09:43 PM) *

My favorite factory 914 rim by far. They look great drooley.gif

All Mahle 5 lug rims were made out of magnesium, not aluminum. If they're made out of anything else they're not genuine Mahle's. Four lug Mahle's were made out of aluminum. Somebody out there makes 5 lug replicas & they are not made out of magnesium.

If I ever did a 5 lug conversion to an LE I would choose 5 lug Mahle's only. Expensive yes, but somehow seems proper to me.



Thanks! Now I know!
porschetub
QUOTE(Johny Blackstain @ Apr 5 2016, 03:43 PM) *

My favorite factory 914 rim by far. They look great drooley.gif

All Mahle 5 lug rims were made out of magnesium, not aluminum. If they're made out of anything else they're not genuine Mahle's. Four lug Mahle's were made out of aluminum. Somebody out there makes 5 lug replicas & they are not made out of magnesium.

If I ever did a 5 lug conversion to an LE I would choose 5 lug Mahle's only. Expensive yes, but somehow seems proper to me.


agree.gif ,they have the look and nothing comes close,imagine if they could retool them to 6,7,8 '' with the right offset that would be a dream come true .....sorry just woke up av-943.gif
Johny Blackstain
QUOTE(porschetub @ Apr 5 2016, 04:17 AM) *

agree.gif ,they have the look and nothing comes close,imagine if they could retool them to 6,7,8 '' with the right offset that would be a dream come true .....sorry just woke up av-943.gif

Oh I have imagined/dreamed/fantasized big time over these wheels. Always wanted a creamsicle w/ GT flares & phoenix red, 5 lug Mahle's that filled them out perfectly- sort of a faux factory look.
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