Can you polish mag caes like Alloy one's

[Slakewell]

Just wondering? I just sandblasted my case and noticed it mag. I was planing to polish some of it and painting the rest. Can you get a high chrome type finish?

[GMC]

No

And Mag. has a protective coating under the paint so it shouldn't really be blasted.
Light scrub and sand & then repaint is recommended

[Slakewell]

No

And Mag. has a protective coating under the paint so it shouldn't really be blasted.
Light scrub and sand & then repaint is recommended

Oppss It's a bit late about the sand blasting tip. But thanks.

[MX?]

And oops again....what sort of coating does it (should it) have under the paint?

[Canam370]

Its a dichromate treatment. Where are you - maybe I can point you in the right direction.

[Lozza]

Passivation and chromate, exposed magnesium will oxidies very fast.

[GMC]

Its a dichromate treatment. Where are you - maybe I can point you in the right direction.

Yeah, that sounds like it. I didn’t think you could get it redone easily though as its very toxic?

[mustanggrahame]

You need a friend who is a licensed maintenance engineer for an airline company.
Cheers, Grahame

[LWC82PE]

You could polish and then clear paint it maybe.

[DR]

This has me confused. I simply sanded and polished my RM400 stator cover with 400g wet and dry then Brasso and it is most definitely magnesium Finished it off to something like a shiny mill finish like alloy fork lowers, just the appearance I was after but it would have polished to a near mirror finish if I'd wanted. Polished TM mag covers also by hand and they came up absolutely gleaming They've all been like that for ages and haven't discoloured, corroded or oxidized, nor have they had any sort of protective spray, clear cote or special treatment since..may have had the odd spray of WD but not that I can remember what have I done wrong!

[David Lahey]

I've seen TY250B/C/D type (magnesium) outer engine covers (which are normally painted silver from new) polished to a mirror finish and used in competition. No idea how often they needed repolishing but the owner wasn't complaining.

[mustanggrahame]

I can't be pure magnesium. Magnesium oxidises so readily that a shaving of it will ignite and burn with a match.
Cheers, Grahame.

[MX?]

I had polished the old covers on the XL ....bad move, couldn't keep 'em shiny for any length of time. I've put later model covers on now and was going to re-paint the old ones, but maybe it won't be real successful without the wacky do treatment first?

[Lozza]

I can't be pure magnesium. Magnesium oxidises so readily that a shaving of it will ignite and burn with a match.
Cheers, Grahame.

Very true .Great care must be taken when machining magnesium, fine swarf can self ignite, can't throw water on it as it will explode

[Nathan S]

"Magnesium" is actually an alloy of magnesium and aluminium (and other stuff) - bikes don't use anything like pure Mg, just like they don't use anything like pure Al.

A story from a rally buddy: He got hold of some fairly pure Mg and either by design or accident, it caught on fire. He buried it in his backyard. A fortnight later, he dug it out, and it instantly re-ignited. He covered it in dirt again, and no further studies are planned.

My experience with "Mg" bike parts is like MX?'s - they polished up nicely and I thought I was a genius. Then they tarnished really quickly and looked like pooh.
I haven't had any dramas with painting over bead-blasted magnesium bits, though.