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Difference Between Type I and Type II anodize

I would like a detailed explanation of the difference in the end product when using Type I or Type II anodize on Aluminum plate. Any Help?

John Hart
1998

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1998

Type I, (chromic acid) is used for parts:

• having riveted or welded joints, or recesses within which is difficult to rinse properly
• which have total dimensional tolerances of from 0.0003" to less than 0.0005"
• where machining after anodizing is not desirable
• with less than 5% copper, no die castings shall be treated by this process.

Type II, (sulfuric acid) is used for parts:

• where coloring and decorative purposes are important
• which require hardness and resistance to abrasion
• on airplanes its use is restricted to parts not subject to stress and not containing recesses in which the anodizing solution might be retained.

Also see MIL-A-8625 / MIL-PRF-8625 [on DLA].

  
Tom Pullizzi
Falls Township, Pennsylvania

What base is anodizing dye. Is it oil or water and can I buy it in small amounts? What is the price?

Billy Doyle
- Grand Prairie Texas us
2000

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It is water based, Billy. You may be able to buy Rit Dye [affil links] in small amounts for a few dollars if your needs are non-rigorous, but purpose-designed dyes for anodizing are more expensive and sold in larger quantities.

You not told us about your needs or the application or the rigors of exposure. Without that input t's kind of like asking how much boats cost. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2000