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RADBMX.CO.UK  |  Technical & Reference Section  |  Tech and Restoration  |  Primo gen 1 cranks - anodised?
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Author Topic: Primo gen 1 cranks - anodised?  (Read 820 times)

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Offline 20to26

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Primo gen 1 cranks - anodised?
« 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?

Offline chubby

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Re: Primo gen 1 cranks - anodised?
« Reply #1 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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Offline Gary72

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Re: Primo gen 1 cranks - anodised?
« Reply #2 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

Offline Gary72

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Re: Primo gen 1 cranks - anodised?
« Reply #3 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.

Offline 20to26

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Re: Primo gen 1 cranks - anodised?
« Reply #4 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:


Offline oldtired

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Re: Primo gen 1 cranks - anodised?
« Reply #5 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.
« Last Edit: November 22, 2018, 06:48 PM by oldtired »

Offline chubby

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Re: Primo gen 1 cranks - anodised?
« Reply #6 on: November 22, 2018, 07:05 PM »
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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Offline 20to26

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Re: Primo gen 1 cranks - anodised?
« Reply #7 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.

Offline midschooljon

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Re: Primo gen 1 cranks - anodised?
« Reply #8 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:
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RADBMX.CO.UK  |  Technical & Reference Section  |  Tech and Restoration  |  Primo gen 1 cranks - anodised?
 

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