crank arm polishing

[legrandefromage]

danson67 has been looking into stripping anodising.

viewtopic.php?f=1&t=391052&start=20

Oven cleaner can work but it can and often marks the aluminium.

There are various recipes on the web using phosphoric acid and chromic acid but this has to be heated and isnt really suitable for home use unless you have a good workshop:

The composition of that bath is 80 grams of chromic acid in 3.5 liters of water, add 140 ml of 85% phosphoric acid, add water to make 4 liters. The bath is operated at 190 - 200 °F. Immerse the part for 15 minutes and then rinse well in water

other than that its a long and painful process with lots of different grades of paper and polish.

 

[gibbleking]

other than that its a long and painful process ..sounds like being married...sounds like a lot of time and effort is required...

 

[legrandefromage]

I have a set of similar period Specialized cranks and they are taking an age to remove the finish.

XT M730 cranks are anodised too so any absurdly shiny ones you meet are not original, whereas the DX were 'bare' and polish lovely.

 

[Peachy!]

Most anodising firms would make a nice job. But with a minimum order charge of £250 you need quite a few bits to make it worth your while & then only if they are for keeps, not worth it if you’re pushing them on. Other option is to get a powder coating company to vapour blast then clear powder coat. But you may as well let the next custodian pay for that. Here are some bar ends I had done recently for £10

 

[gibbleking]

id forgotten about having the sprayed.hmmmmm

 

[Peachy!]

id forgotten about having the sprayed.hmmmmm

No paint on these, that’s fine vapour blasting then clear powder coat. Much tougher than paint

 

[dyna-ti]

I've found a belt sander very good for removing the grounding marks from the end of the crank.