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Anodizing
Stuart_B - 23/7/08 at 03:48 PM

hi all, is it possibly to Anodizing copper?
as well what do you need to Anodize copper? and where to get the parts from?

thanks

stuart


nick205 - 23/7/08 at 04:02 PM

You can't anodise Copper, but it does paint and powder coat nicely.

Why did you want to anodise it?


Stuart_B - 23/7/08 at 04:06 PM

quote:
Originally posted by nick205

Why did you want to anodise it?


just so i can say i have had a go with Anodizing, and i have some copper water pipes and a copper oil cacth tank.

so you can only anodise alu or can you anodise any think else?

thanks

stuart


tomblyth - 23/7/08 at 04:55 PM

No but can be treated to simular protective layer

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, although processes also exist for titanium, zinc, magnesium, and niobium. This process is not a useful treatment for iron or carbon steel because these metals exfoliate when oxidized; i.e. the iron oxide (also known as rust) flakes off, constantly exposing the underlying metal to corrosion. "Stay-Brite" is sometimes used as market name for products made from anodised aluminium such as brass replica.
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.


Copper can be treated though to form a similiar protective layer. exposed to the air and water, an oxidation reaction takes place that changes the color of the cooper. First the copper changes from pink to brown, thin to black. Finally the copper is covered with a blue-green material called patins (puh-TEE-nuh). The patina is made of copper sulfate, a compound of copper and sulfur. (some times called Verdigris )Once copper has a patina, corrosion stops and the cooper may lasts for hundred of years. see St paul dome or the Statue of Liberty

[Edited on 23/7/08 by tomblyth]


David Jenkins - 23/7/08 at 05:07 PM

The down-side is that the patina is poisonous! (ask anyone who has to handle old copper).

As an aside, one traditional way of turning a new copper roof green was to pee on it! Not that I'm recommending it, you understand...