what are judy lowers made from?

[cherrybomb]

Eyebrows.......what eyebrows?

 

[scant]

And I think they'd need to be clear-coated over the top to stop any corrosion.

But not impossible...

Having paint or lacquer on them causes more corrosion than it prevents cos it traps water against the metal and boy does mag oxidise when it gets going!

is that right? why would rock shox, fox paint the forks if it wasnt required?

to answer the question yes you can polish magnesium, but its not as easy as, say plain alu. mark pearce of bromley bike did it to his mag21s BITD (on his 93 fat chance ti) & it looked very cool

 

[cherrybomb]

And I think they'd need to be clear-coated over the top to stop any corrosion.

But not impossible...

Having paint or lacquer on them causes more corrosion than it prevents cos it traps water against the metal and boy does mag oxidise when it gets going!

is that right? why would rock shox, fox paint the forks if it wasnt required?

to answer the question yes you can polish magnesium, but its not as easy as, say plain alu. mark pearce of bromley bike did it to his mag21s BITD (on his 93 fat chance ti) & it looked very cool

In Rockshox case...yes it is. Magnesium alloys oxidise badly if they cannot dry properly and moisture is given no where to go, much worse than aluminium alloys. You get a white powder on the surface. Unfortunately badly applied paint or lacquer finishes cause the best environment for rapid oxidisation hence blown paint being so common on the legs of Judys. (Everyone's seen it around the dropouts and canti studs where the paint gets chipped). If you are gong to keep them waxed and regularly maintained then polished finishes are a much more sensible idea.

 

[scant]

i'll check this with my mate who works on deep sea oil rig applications.
i know in this context alu parts dont have any protection applied, as the white oxide layer that develops IS the protection... & these are parts holding a sh,t load more weight & stress than any bike frame/part will ever see.

 

[cherrybomb]

On the rare occasions that aluminium alloys are used in marine environments they will almost certainly have some kind of surface treatments where high tolerances are necessary. On other applications steel alloys are far more commonly used or plated brass and bronze.

It's also important to remember that the conditions underwater are completely different to a wet suspension fork sitting in a garage with loads of lovely oxygen around.

The alloys used in marine engineering are not the same as the ones used for making suspension forks either. They are specialist materials designed to have very specific characteristics.........(the North Sea Oil industry ca afford it. ) suspension forks are made of very low grade material.

Finally, magnesium and aluminium alloys are very different beasts, where the oxide coating on aluminium stays attached to form a hard protective layer, the oxide formed on magnesium is soft and easily removed and offers little protection to the metal beneath it.

I spent my early working life as a marine engineer and the quality of 'bike' related stuff constantly scares me.

 

[gump]

I polished up some of my Judys, and they looked well tasty. But it does dull very quickly and look a bit rough then. I used a powertool too
Decided this whas not massively practical without some clearcoat protection or something. Yep, they are magnesium.

 

[rc300]

My new sid's "Just add water"