Ok ive watched, aaroncakes vids, pineapples videos, and researched on the forums back to 2002. Spent the day cleanin some rotors in the parts washer. I worked on one rotor while the other soaked in the deeper end of the tub. Used a Water based degreaser.

Spent about an hour this morning scrubbing what i could off the rotors, It wasnt doing much good so i left them in the tub to soak for about 2 hours, came back and hit them with the Brass wire brush again and made some good progress. What i found was on the inside and outside face, i had these weird little spots appear. Its not physically damaged, i cant feel any difference, its still smooth.

After seeing this i took them out and ran them under warm water in the sink, and dried them off.

Ive read of people soaking their rotors in simple green, kerosene ect for days before cleaning.

Any ideas as to whats goin on here? Im not sure if i fucked them up here somehow.

 

Kancer!

 

The spots are where the cadmium plating has been etched away by the cleaner. It's no problem.

Few people end up preserving the plating when cleaning rotors. Always amusing to see pictures of beautifully clean raw steel rotors proudly posted up, only to realize that the rotors should be gold due to the plating. Functionally there's no difference...just the lack of plating makes them more prone to surface rust if left in the open air.

 

phew!, when i started cleaning these i saw nothing but beautifull goldness, and i remember in your video you saying that its a good indicator....so i had my hopes up! and then i saw the spots later in the afternoon and i started bangin my head on the wall lol

 

Something I've never heard before, good to know.

 

Oh thank god i just started cleaning mines and was hella worried

 

Cadmium has a LOWER melting point than Lead. I'd say after 20+ years of combustion chamber service, the cadmium is gone, no?

PS
the rotors would be raw iron, not steel

 

the rotors are steel. and i believe it is zinc, not cadmium.

try to avoid letting the rotors sit in water based degreaser for more than a day at a time to avoid the plating from getting etched.

 

yarg!!!

 

Ehh.. Cast iron but, almost like cast steel. Not steel. If you machine on one the chip is powdery and small (typical cast iron is a powder). They will dent or deform (unlike what we all think of when talking about cast iron) and are extremely soft. The Mazda video shows them hardening the corner seal area. Cast iron has a hardness but heat treating and quenching have only slight effects as opposed to carbon and alloy steels.

Your guess is as good as mine but I say it's somewhere in between like a ductile cast iron/cast steel.