Anodizing XT cranks.

[Drew.]

Just a plain and simple question, would it be possable to anodize a pair of Shimano XT cranks black? Or would the anodizing that's already on it have some affect?

Cheers.

 

[bighitter]

no you cant, due to the steel spindle

 

[skwiz05]

no you cant, due to the steel spindle

Oh yes you can...but dont just take it to any one....

Research the companys processes for anodising as they are not all the same.

Depends on which chemical/processes are used.

If done carefully, the ally should anodise fine, with the steel insert probably blurry or maybe slight stain, but have to watch the join (interface area) between the two metals. Masking is possible. Best bet to remove old surface (rather than acid dip) is bead blasting.

And youll probably get away with a thin (cosmetic) finish rather than a 'hard' ano finish due to having to be careful with the steel.


Just do your research and you'll be right.

 

[bighitter]

It can't be done, as the steel spindle will corrode

you can polish them up and they look awesome though

 

[ovadahill]

you can polish them up and they look awesome though

or buy Saints

 

[udi]

Skwiz -
Bighitter is correct, you don't seem to understand how anodizing works. You cannot expose steel/chromoly parts to anodizing (read below for why). Also, the XT cranks have a pressfitted steel spindle (ie axle) into the driveside arm, not pedal inserts. You would damage either obviously, but the spindle is going to be near impossible to mask/work around and still have the full driveside arm neatly anodized.

So put bluntly, no it is not possible to anodize them

Edit -
I'm no chemistry buff (calling toodles) but to my knowledge anodizing forms an anodic oxide layer over the aluminium which helps protect it, whereas it will have the opposite effect on steel and greatly increase corrosion (iron oxide = rust). I've also read multiple times that steel/brass/bronze will actually burn off in the anodizing tank unless masked. Steel needs a cationic coating to protect it.

 

[skwiz05]

Skwiz -
Bighitter is correct, you don't seem to understand how anodizing works. You cannot expose steel/chromoly parts to anodizing (read below for why). Also, the XT cranks have a pressfitted steel spindle (ie axle) into the driveside arm, not pedal inserts. You would damage either obviously, but the spindle is going to be near impossible to mask/work around and still have the full driveside arm neatly anodized.

So put bluntly, no it is not possible to anodize them

Edit -
I'm no chemistry buff (calling toodles) but to my knowledge anodizing forms an anodic oxide layer over the aluminium which helps protect it, whereas it will have the opposite effect on steel and greatly increase corrosion (iron oxide = rust). I've also read multiple times that steel/brass/bronze will actually burn off in the anodizing tank unless masked. Steel needs a cationic coating to protect it.

I did say masking is possible....so you are no chemistry buff...
Please explain my nice nice shiny blue anodised cranks then??????????????????????????????????????????????????????

And I DO understand perfectly how anodising works....(as its one of the many jobs the company I part own does...)

A 10-15 micron surface is possible, but going for a 80 mic hard finish probably will damage the steel.....


And heres one for the sceptics then.........Can you make a piece of wire cut (or erode) diamond?

 

[fatnold]

i would be extremely careful with the mixed metals and anodising. i carelessly sent a prep'd frame for anodising with the drink bottle mount inserts in tack. the frame came back with the bottle mounts gone...ie, eaten away. and yes i had instructed to do only a light etch.

 

[udi]

I did say masking is possible....so you are no chemistry buff...
Please explain my nice nice shiny blue anodised cranks then

Aren't you a polite little princess today. If you actually owned a pair of XT cranks you would see the difficulty in masking the spindle from both sides in such a way that acid did not reach them.

Are your nice shiny blue anodized cranks M760 SHIMANO XT's? Didn't think so. Also refer to above post by fatnold.

 

[toodles]

Nope. Attempting to do so would dissolve the steel out of the aluminium. In fact, the redox reaction at the aluminium/steel interface would get very hot and crack the aluminium around the spindle. With aluminium's entropy, the steel would become a sacrificial cathode and would dissolve rapidly in the solution. There are specialist anodising mobs who would give the job a go, but it would be silly expensive.

Polishing XT cranks looks sick.

 

[skwiz05]

Aren't you a polite little princess today. If you actually owned a pair of XT cranks you would see the difficulty in masking the spindle from both sides in such a way that acid did not reach them.

Are your nice shiny blue anodized cranks M760 SHIMANO XT's? Didn't think so. Also refer to above post by fatnold.

My XTs are older, but have steel inserts, and came out quite fine.

BUT, yes its not an easy process, wasnt denying that. The question asked was: is it possible? Answer was yes. However, the likelyhood of him finding someone other than the run-of-the-mill anodiser who would have the right gear or guts to risk doing it safely is slim.

We have also played with monel sheeting...and for those in the know its a also a bitch to work with....



And as a further sidenote to my earlier wire/diamond question.......the machine is called an EDM. Havent found a material we cant cut with the electro-discharge process.