How do you paint Magnesium?

**RobGassit** · 9th June 2011, 12:12

I would appreciate some advise on painting Magnesium please. I have some Marvic wheels and other assorted parts such as swingarm, triple yolks and engine covers. I have the following worries:
a;Stopping corrosion,
b;Not adding too much weight, ie: 5 coats of paint,
c;Would rather do it myself as the parts are rare and valuable so I'm reluctant to give them to some powdercoater who may acid dip them or something and turn them to dust.

I have tried brake caliper paint, fine until exposed to environment for a period of months.
Engine HT paint. Even several coats and baking it only lasted months on a flywheel cover.Possibly my preparation was not adequate or there was salt or some such deep in the material.

Happy to take recommendations on professionals who can be trusted or any advise gratefully received. Cheers.

**Jantar** · 9th June 2011, 12:23

Originally Posted by RobGassit

I would appreciate some advise on painting Magnesium please.....

Happy to take recommendations on professionals who can be trusted or any advise gratefully received. Cheers.

I am not a painting proffessional, and really know very little about paint. But I do something about magnesium and how to handle it. First, I doubt that the items are pure magnesium, rather they will be an alloy of magnesium and that alloy will affect they type of material that can be used. Pure magnesium will corrode rapidly on contact with water.

Be very carefull with any material applied to magnesium, even if it is an alloy.

**marty** · 9th June 2011, 12:35

magnesium really needs to be treated with an anti-corrosion product prior to painting. And they will be magnesium alloy - 100% mag is too soft (but super light!). an old-school aircraft engineer would know

**RobGassit** · 9th June 2011, 12:43

Originally Posted by marty

magnesium really needs to be treated with an anti-corrosion product prior to painting. And they will be magnesium alloy - 100% mag is too soft (but super light!). an old-school aircraft engineer would know

Thanks guys. Yes obviously they are magnesium alloy. Sand cast and paper light though.

**imdying** · 9th June 2011, 12:47

Dymag in the UK used to have a magnesium wheel repainting service, might be worth asking them. Please let me know what you find out, I have a set that needs redoing myself.

**RobGassit** · 9th June 2011, 12:51

Originally Posted by imdying

Dymag in the UK used to have a magnesium wheel repainting service, might be worth asking them. Please let me know what you find out, I have a set that needs redoing myself.

Will do cheers.Watch this space. Some boffin will cough up a result quick smart. I have complete faith in the KB crew..

**imdying** · 9th June 2011, 13:46

**slofox** · 9th June 2011, 14:31

I have a regular customer who works in aircraft assembly here in The Tron. I'll ask him next time he's in...very clued-up dude.

**Grumph** · 9th June 2011, 16:04

The parts need to be beadblasted - but it must be clean dry bead as any contamination, particularly steel will lead to corrosion probs.
Once clean they should be corrosion proofed with a chromate etch prime.
Finish with baked enamel and clear coat - or just clear coat over the chromate.

I've got a Dymag here I made the mistake of powdercoating - chipped round the bead now and I'm really reluctant to try and remove the powder.

**98tls** · 9th June 2011, 16:16

What about anodising them?,didnt think you could myself but http://www.magnesium-elektron.com/ab...esium.asp?ID=2

**DEATH_INC.** · 9th June 2011, 16:24

Originally Posted by Grumph

The parts need to be beadblasted - but it must be clean dry bead as any contamination, particularly steel will lead to corrosion probs.
Once clean they should be corrosion proofed with a chromate etch prime.
Finish with baked enamel and clear coat - or just clear coat over the chromate.

Yup, but I just used a 2k enamel over the etch....

**RobGassit** · 9th June 2011, 16:39

Thanks guys. It's really flooding in now. I have my own blasting box but I'll have to get hold of some beads. I was aware not to use sand. Keep it coming please. Happy for the recommendation of brand products to trust for the chromate and paint.

**imdying** · 9th June 2011, 16:46

I had a snoop around the net, and somebody mentioned not to blast them at all as it has the potential to hide cracks. They suggested doing it the hard way (by hand), but provided no hard evidence

/edit: Having said that, there's plenty of videos on youtube showing soda blasters that people have made themselves... surely can't get much gentler than that?

**gatch** · 9th June 2011, 17:02

Originally Posted by imdying

I had a snoop around the net, and somebody mentioned not to blast them at all as it has the potential to hide cracks. They suggested doing it the hard way (by hand), but provided no hard evidence

/edit: Having said that, there's plenty of videos on youtube showing soda blasters that people have made themselves... surely can't get much gentler than that?

Soda.. Sodium chloride ? Salt ?

Is that wise considering the lack of corrosion resistance of the mag alloy ?