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Amsterdam, Netherlands
Welcome to my BLOG about my pasion for retro mountainbikes and everything around that. I love to read your comments in the GUESTBOOK (on the right side) or email me : basads (at) gmail (dot) com thanks for reading, Bas

Saturday, 22 November 2008

De-Anodizing bike parts

Let me first explain wat anodizing (anodising) is;

Anodizing, or anodising, is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. Anodizing increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than bare metal. Anodic films can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light. Anodizing is also used to prevent galling of threaded components and to make dielectric films for electrolytic capacitors. Anodic films are most commonly applied to protect aluminium alloys.
Anodization changes the microscopic texture of the surface and can change the crystal structure of the metal near the surface. Coatings are often porous, even when thick, so a sealing process is often needed to achieve corrosion resistance. The process is called "anodizing" because the part to be treated forms the anode electrode of an electrical circuit. Anodized aluminium surfaces, for example, are harder than aluminium but have low to moderate wear resistance that can be improved with increasing thickness or by applying suitable sealing substances. Anodic films are generally much stronger and more adherent than most types of paint and metal plating, making them less likely to crack and peel.

I received a Syncros seatpost a couple of weeks ago and this arrived a bit more scuffed then expected, in a condition i do not use for my bikes and therefore i was thinking about de-anodizing the post (and maybe re-anodize in the future) so it looks better then scuffed black.
I've looked around on the internet and found out that putting the item for 5 minutes in caustic soda will do the trick (caustic soda is used to unblock a blocked sink.
Because i did not want to try it on the seatpost to start with i took some old Hope QR's apart and put them in,..
These were scuffed too and i couldn't care less if it went wrong ;)

This is how they looked;

and this is what i used.
Unfortunately is it in Dutch but it is a 2 component soda from the brand HG

You have to put from both bottles even parts in a small box (I use the old Chinese restaurant rice boxes ;) )
enough to put the part under

I put it in,..and after 2 minutes you could see the soda do it's work

After 4 minutes i took it out with a clamp and rinsed it of with cold water.
It turned black but all the red was gone.

I took some stainless steel polish and polished it up,..and the black came right of,..
After that i took some silver polish but i do not know if that made a difference although the cloth became grey using it.
This is how it looked after the polishing, the whole "project" took about 20 minutes,..and the result looks nice
Even the HOPE brandname is still visible

Next up was the seatpost.
Because i did not have to box big enough i used my parents sink and the yellow patch.
I put it in the caustic soda en put it on the post and almost immediately the black came off (purple)

Same process, rinse with water,..and polish,...
Also very satisfied with the result.
Black Syncros decals are on it;s way from Gil_M

I am very pleased with the result , especially if you look at how easy it goes.
There are also some ovencleaners that might work,..bit "saver" but less strong so my might have to put the parts in longer to get the same result


Casper said...

Wow, good tip! I want to build my own retroish bike but I want all the items to be black. With this tip I don´t have to pay attention to colours that are on Ebay.
Do you know if this process has any consequenses for reanodizing=



ADHD No12 said...

Hi Casper,

from what i heard this process is a good one when you are about to reanodize,.
But do you want to do that yourself? i guess not,..i might want to have the seatpost reanodized here in amsterdam, i will kep you guys posted.


Kunal said...

Hi there. Nice blog. You have shared useful information. Keep up the good work! This blog is really interesting and gives good details. aluminium components, aluminium gravity die casting.

micheal johnson said...

Metal components are getting popularized these days so often.These components which are not only used in bikes but also in other vehicles too. For a metal component to be used for a longer period then it should be made out of good quality.So buying good quality Metal Components will be the right choice for that.