mike blood

Topic: Part is longer than the tank

Good morning,

I'd like to pose two questions: #1= Let's assume you have some 6061 parts that are physically longer than your baths. Can you clean, desmut, anodize, dye and seal one half and then flip the part around and repeat the process and get away with it?

#2= My anodizing line is a small home / hobby type line using several 6 gallon coolers. I get varying results in the outcome of the parts especially when dying black. I've tried anodizing @12 amps for an hour and lower amperage for longer periods of time. My guess is that due to the size of the bath, the temperature is getting away. My question is this: Better to anodize at higher amperage for less time, or lower amperage for longer. Thanks in advance for any insight anyone might have - Mike


Re: Part is longer than the tank

#1: Generally, this approach will fail.

#2: Typically, the lower the temperature and the higher the current density, the harder the oxide layer will be. When you see kitchenware that is hard anodized, this is what they are doing (kinda sorta). A lower current density and higher temp will give you a softer layer, and your colors and dyes may look washed out. If you want repeatable, consisten color, you need to control your temperature. Use an ice bath outside of your tanks. Make sure you have good solution movement.You can even use a small pond pump (Eheim) inside of an ice bath and have it pump the ice water through a heat exchanger (titanium or aluminum), which is inside the anodize bath.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC

mike blood

Re: Part is longer than the tank

Dustin, thanks for the response. I'll give that a shot