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Corrosion on fork lowers

valve bouncer

Master Dildoist
Feb 11, 2002
7,843
114
Japan
I bought these forks recently and the seller didn't disclose this area of bubbled paint around where the cable guide goes and it couldn't be made out in the pictures. The fork was sold on an "as-is" basis. I'm not sure how concerned I should be about this and was wondering whether they are rideable in this state or is it a lost cause. I'd like to get some views on this before I contact the seller and/or leave negative feedback for him. Fork is a Fox Float 32 RLC. Last photo is the sellers for reference.
WIN_20201217_20_54_21_Pro.jpg
WIN_20201217_20_56_53_Pro.jpg
i-img798x1200-1607600043kpuhym1088035.jpg
 

Nick

My name is Nick
Sep 21, 2001
23,928
14,450
where the trails are
I think those lowers were magnesium, and magnesium doesn't corrode very easily. I'd scrape the paint off and see if it's showing signs of a problem. More likely there was some minor damage or rub and they did a shitty job of repainting over it.
 

canadmos

Cake Tease
May 29, 2011
20,192
19,158
Canaderp
Don't know. Are you thinking brake fluid?
It could be possible, maybe some dripped down while bleeding the lever? Though I've not seen what dot fluid does to paint personally, like does it bubble like that or just turn it to goop?

Are the bubbles squishy or solid?
 

Jm_

sled dog's bollocks
Jan 14, 2002
18,855
9,560
AK
I think those lowers were magnesium, and magnesium doesn't corrode very easily.
ummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm...

I know there have been corrosion issues with magnesium in aerospace. Not sure if it's just oxidation or galvanic though.
 
Last edited:

Westy

the teste
Nov 22, 2002
54,241
20,022
Sleazattle
Magnesium corrodes very easily to the point where it can catch fire. I know, I have burned some lowers in a fire.

However magnesium bike parts are alloyed with aluminium which gives them better corrosion resistance.
 

Westy

the teste
Nov 22, 2002
54,241
20,022
Sleazattle
If returning the fork isn't an option I would sand/scrape it back to inspect. If all is good respray.

I would say the bubbled paint is more of a liability as it can trap sweat and moisture and accelerate corrosion.
 

valve bouncer

Master Dildoist
Feb 11, 2002
7,843
114
Japan
If returning the fork isn't an option I would sand/scrape it back to inspect. If all is good respray.

I would say the bubbled paint is more of a liability as it can trap sweat and moisture and accelerate corrosion.
I don't sweat. I glisten.
 

Nick

My name is Nick
Sep 21, 2001
23,928
14,450
where the trails are
ummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm...

I know there have been corrosion issues with magnesium in aerospace. Not sure if it's just oxidation or galvanic though.
Magnesium corrodes very easily to the point where it can catch fire. I know, I have burned some lowers in a fire.

However magnesium bike parts are alloyed with aluminium which gives them better corrosion resistance.
Im not a real scientist. :nerd:
 

Westy

the teste
Nov 22, 2002
54,241
20,022
Sleazattle
Im not a real scientist. :nerd:

Fun fact: Magnesium likes oxygen so much it is used to manufacture titanium. Titanium oxide is reduced by mixing it with molten magnesium which strips the oxygen leaving pure titanium. Titanium is actually very plentiful but is expensive because you basically have to purify magnesium to purify titanium.
 

crashmtb

Chimp
Dec 14, 2020
40
41
I’m not a materials engineer, but that looks like filiform corrosion. Did that fork come from a humid place with salty air?