I've learned something today.......

[Jan-Cor]

Yeah really, I have a new experience I like to share with you retro builders!

Recently I bought a nice AC Crankset complete with small chainring and red anodised spider.

Because of my Retro project, I do like silver, alu or whatsoever, but not red.
So I did some surfing on Google how to remove the anodised layer of aluminium.
And I did find it to make a long story short: put it in some caustic soda, wait a few minutes, use lots of water to clean it and you're ready

Yeah, totally true. Unfortunately it also lost some aluminium material :facepalm: :facepalm:
The chainring bolts do not fit anymore, the tread is still in but the tread diameter is far to wide, the bolts fall through the hole :roll:
The holes to mount it on the crank are also wider, still fits but has some play....

Probably I did use too many caustic soda (not too long, it was only two minutes) or the caustic soda is too aggresive, I am not sure at this moment.
Unfortunately I did not measure the spider before the treatment.
The colour is right, yeah.......that's true :mrgreen:

Can someone help me to get a new spider in aluminium or black colour ?? :roll:

I just want to share it with you guys, so: be carefull when you are thinking about removing the anodised colour

 

[Rampage]

Re:

What temperature was the caustic soda?

 

[Jan-Cor]

Re: Re:

What temperature was the caustic soda?

just these small white balls and added boiling hot water on it.

 

[sparkiegaz]

Great for clearing blocked toilets and drains also feller,,don't stand with you hand in the water tho,,,,

 

[Rampage]

Re:

You should use cold water, you can get a very nasty reaction and it can explode adding it to warm / hot water. The fumes given off at those temperatures can badly injure you also.

That's why it happened.
Why did you add boiling water?

 

[Jan-Cor]

Because the description on the bottle did say so.
It is normally used if you have a clogged drain.

 

[poweredbypies]

Have used caustic to strip anno plenty of times think you left it to long.

 

[Jan-Cor]

Only 2 or 3 minutes, no longer !

 

[Rampage]

Re:

http://www.sciencelab.com/msds.php?msdsId=9924998

If it says to use with boiling water then that is ******* irresponsible.

 

[spokes]

Re:

I put a new hard anodised saucepan in the dishwasher and it came out stripped of its anodised bottom. Maybe that would work for bike parts also. If not at least they would be very clean..