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Technical & Reference Section => Tech and Restoration => Topic started by: 20to26 on November 21, 2018, 02:37 PM

Title: Primo gen 1 cranks - anodised?
Post by: 20to26 on November 21, 2018, 02:37 PM

Hi, I have a set of Primo gen 1 cranks that I want to polish up for a new build - does anyone know if they were anodised or can I just polish away?

Title: Re: Primo gen 1 cranks - anodised?
Post by: chubby on November 21, 2018, 02:44 PM

Mine had a flaking clear coating over them. Didn't come off with paint stripper or oven cleaner. Had em vapour blasted in the end..

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Title: Re: Primo gen 1 cranks - anodised?
Post by: Gary72 on November 21, 2018, 07:31 PM

I’ve got a set that also appear to be flaky, Never looked closely but kinda of assumed it was chrome flaking like chrome rims of the 90’s

Title: Re: Primo gen 1 cranks - anodised?
Post by: Gary72 on November 21, 2018, 07:34 PM

I did have a later set that seemed to have a very slightly rough finish. I sand blasted them and painted them satin black and ended up with a really nice finish.

Title: Re: Primo gen 1 cranks - anodised?
Post by: 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:

Title: Re: Primo gen 1 cranks - anodised?
Post by: oldtired on November 22, 2018, 06:35 PM

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.

Title: Re: Primo gen 1 cranks - anodised?
Post by: chubby on November 22, 2018, 07:05 PM

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:

Same as mine were dude

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Title: Re: Primo gen 1 cranks - anodised?
Post by: 20to26 on December 05, 2018, 11:50 AM

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

Title: Re: Primo gen 1 cranks - anodised?
Post by: midschooljon on December 29, 2018, 11:06 PM

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: