Indy-Guy
Indy-Guy UberDork
3/1/19 10:52 p.m.

As the title says, I need to prep and paint these. 1994 BMW E34, M60. The internet says they're made of Magnesium alloy.  How do I prep them? & What type of paint & or primer?

GTXVette
GTXVette SuperDork
3/2/19 4:13 a.m.

clean as any other metal Heat it to 100 + degrees not too hot and spray with Wrinkle Black while warm, The heat helps it wrinkle

TurnerX19
TurnerX19 Reader
3/2/19 8:37 a.m.

Media blast with glass or walnut shell. Do not use sand. Then, if wrinkle is OK GTXVette is on track. If you dislike wrinkle you need a self etching primer beneath your color. 

Indy-Guy
Indy-Guy UberDork
3/2/19 1:25 p.m.

In reply to TurnerX19 :

What if media blasting is not an option?  Just use paint thinner / engine degreaser / brake cleaner ?  Then blow dry and prime?  I don't care for crinkle paint.

Ranger50
Ranger50 UltimaDork
3/2/19 1:48 p.m.

Scuff pad/brake cleaner then acetone/wipe then self etch prime?

Dr. Hess
Dr. Hess MegaDork
3/2/19 1:52 p.m.

If no media blaster is available, then lots of elbow grease.  I'd start with paint stripper, then sand it or use one of those wheel things in a drill.  Get it all off and uniform. Degrease.  Run through the dishwasher and take it out before the dry cycle.  Then bake it in the over for an hour at like 400F.  Do that while the spouse is away.  Then hit it with whatever paint you want.  I've had good luck with Rustoleum Professional products.  Best to apply when still warm.  Then back in the oven at like 200F or so for a half hour to bake it on.

Indy-Guy
Indy-Guy UberDork
3/2/19 2:28 p.m.

On second, thought, I have access to a sand blaster at work...

Why not use a sand blaster?

Cousin_Eddie
Cousin_Eddie HalfDork
3/2/19 4:02 p.m.

There is nothing wrong with media blasting that cover as long as you can assure that there are no cavities or areas where stray media can hide and then come loose into your engine later. Assuming no baffles or anything like that, blast away.

TurnerX19
TurnerX19 Reader
3/2/19 6:59 p.m.

If sand is your only media blast option I would do the hand sanding labor intensive cleanup like DrHess proposed. I am uneasy about the chemical relationship with sand versus magnesium. Clean out comments remain with any media, get it all out! Also I think 400 degrees is too hot, it risks a permanent warp if the casting is not perfect. Note that most of my magnesium experience is with English race car castings from original Can Am and F5000 cars, where there are no perfect castings. Rustoleum satin dark walnut made them look almost original, it was as close as we could get to the EPA forbidden black electro coating they had when new.

Appleseed
Appleseed MegaDork
3/2/19 11:02 p.m.

I've never heard of sand chemically reacting with anything. 

NOHOME
NOHOME UltimaDork
3/3/19 5:56 a.m.

I would glass bead if I could.

Etch prime is the go-to for the aviation industry and I would get a can of that for your job.

Wrinkle paint out of a can gives me hives because the results are so variable no matter what you do and I have tried all the tips and tricks known to the internet. If you must have krinkle, have it powder coated  or know that 50-50 are your chances of getting it to work out of the can

GTXVette
GTXVette SuperDork
3/3/19 6:10 a.m.

In reply to NOHOME :

Funny you say that as only a couple times out of MANY did I have a redo.    I even got great results Spraying the Spoiler Lip on the nose of the Fiero , Using a Hair Dryer

AngryCorvair
AngryCorvair GRM+ Memberand MegaDork
3/3/19 7:44 a.m.

On my E38 I soaked and scrubbed them in the parts washer, then went over the entire surface with a wire wheel in an electric drill.  Then washed them in hot soapy water, rinsed, then dried with compressed air and sunshine.  Then I used the black wrinkle paint over top of the recommended primer.  They still looked pretty good when I sold it 6 months later.

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