| are the marchesini's alloy or magnesium?
if they are alloy, fine, paint or powder coat, either is an option.
if they are magnesium, be aware, they have a zinc di-chromate coating that protects the magnesium from moisture absorption from the atmosphere, this causes corrosion and makes the material weak and brittle, NOT GOOD! if they are mag, don't get them blasted unless you know you can get the zinc di-chromate plating re done. when getting them painted i would reccomend asking for a dry rub with a scotchbrite pad and painted wet on wet. the finish won't be as perfect as a proper wet rub and sanding between coats but it will ensure the coating stays sealed and intact.
powdercoating magnesium doesn't in itself cause problems but again, they will want to blast them first and there goes the zinc di-chromate coating, another issue is the thickness of the powder, it makes it very difficult to see corrosion taking hold underneath, often looks like crazy trails lifting under the surface, if you see this on wheels you are thinking of buying, run a mile...quickly.
hope it helps,
cheers,
paul.  |