Technical & Reference Section > Tech and Restoration

Primo gen 1 cranks - anodised?

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oldtired:
machine polish ?   sizal mop with rough/first cut compound will take off the black and  or any coating on them  :daumenhoch:   

try a quick dip in caustic soda, if it's anno the black will come off more or less straight away ,  don't think they are, but, if they're  hard anno has to be polished/cut off as it's part of the alloy not a dye on the surface.

chubby:

--- Quote from: 20to26 on November 22, 2018, 09:19 AM ---Thanks guys. This is what mine look like at the mo, I can’t quite tell if there’s a clear coating but I suspect there maybe now based on what you’ve said:

--- End quote ---
Same as mine were dude

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20to26:
Thanks guys. Looks like I'll need to send them to a polishing shop to get a pukka job done.

midschooljon:
They are anodized but the quality of alloy was bad so when you put them in caustic soda "smutting" occurs. Its basically the impurities in the alloy recating with the solution that has removed the anodizing. To get rid of the black "smutting" you need to put them in an anti oxidant solution just like you would to remove rust.

The only times I have ever had to do this was on early primo cranks, and first gen S&M clamp on stems. Ironically both these parts came out around the same time, so the alloy doing the rounds in the late 90's must have been full of rubbish.  :LolLolLolLol:

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