Anodised Crank Arms, Blue Doesn't Match. Darken, lighten or remove?

[Wayne Ryder]

Expertise needed, gents.
Some years ago I bought an Odyssey Black Widow crank. When it arrived the arms were odd lengths (175 and 180 I think), which came as news to the seller who'd used them for ages and not noticed. He kindly offered a return, but it seemed very possible that sooner or later I'd find a donor arm. Every so often I'd check our favourite auction site, but nothing for bloody ages.
When one appeared last week, I pounced on it.

Well, it arrived and it's tip-top. S'just I'm not sure about the colour. My original pair is a darker blue, the 'new' arm is much lighter.
So, is there a way of fading the darker arm? Would it be better to wait several more years and get them both redone? Would that even work, since they're not bare to start with?
Or is it a case of strip & polish, or possibly paint?

[oldtired]

 i assume there are anodized,  its easy to take the color off if they are  ,i don't think silver black widows were polished so it'll easy just to clean em after the color is gone , this will be the simplest and quickest option

you can fade the anno with a mild caustic solutuion but its very hit and miss and the parts have to be very clean before you start to avoid a patchy finish ,parts i've faded look as if they are old and been used , the anno tends to dissolve quicker on the coners of parts,

the only way to ensure a good color match is to have them re anodized , 

[BMX1973]

Is all the arm coloured? Would anyone notice as on opposite sides? If you can live with it at least you can keep the original finish. 

[deeman]

Is all the arm coloured? Would anyone notice as on opposite sides? If you can live with it at least you can keep the original finish. 

^^this.....as they on opposite sides is it really that noticeable?

[MartyC]

The anodising fades in sunlight/uv so try placing the darker one on a window sill that gets a lot of sunlight for a few weeks 

[BMX1973]

If your not going to use them at the moment, try this. Or if you can hold on until the summer even better. Then you can retain the original finish. 

The anodising fades in sunlight/uv so try placing the darker one on a window sill that gets a lot of sunlight for a few weeks 

[Wayne Ryder]

If your not going to use them at the moment, try this. Or if you can hold on until the summer even better. Then you can retain the original finish. 

The anodising fades in sunlight/uv so try placing the darker one on a window sill that gets a lot of sunlight for a few weeks 

Thanks everyone, this is all useful stuff. There is a noticeable difference in shades of blue, unfortunately.
The UV fading might work, but will probably take till next September. I tried this on a pair of shoes, one of which I'd not noticed had some display fading. Didn't really work on suede. I can't help wondering if anyone I know has a sun bed...

[oldscool]

Spray on oven pride works. Spray it on as fast as possible so its on an even length of time an clean it off quickly, Keep doing it until you get the shade you want. 

[Wayne Ryder]

Spray on oven pride works. Spray it on as fast as possible so its on an even length of ttime an clean it off quickly, Keep doing it untill you get the shade you want. 

That sounds just like my kind of method. Might give that one a punt.

[Chris123]

Using sodium hydroxide to try and fade anodising is a stupid idea. The dye is trapped in the anodising, removing the top of the anodising will open the pores where the dye is contained, it'll all come out, you can't control how much you remove!

It's unlikely two weeks in the sun will do anything, perhaps you could leave them there for a couple of years on a kebab rotisserie so they are evenly faded?!!!!

Get them re-anodised at a company that is used to re-anodising parts.

[CustardLips]

Sounds like a load of fookin about to me... get em stripped and re-anoed or strip and polish em.