Rectifier Voltage

[anodizeme4ever]

We are in the process of having a rectifier built to accomodate future plans. Wanted to know if anyone has any experience with these - looking at having a 200 - 300 amp built and want to know if the voltage needs to be any higher than 30 volts for anodizing.

[sswee]

I'd be happy to find one that would do 50 or 100 amps CC that wouldn't break my bank. 30V should handle up to a 12 ASF. It all depends on if you will want to get into the higher CD's.
SS

[anodizeme4ever]

So, would you go higher on the voltage to do say 3000 sq. inches?

[sswee]

The voltage needed depends on the current densities you are going to run. Running a 3000" SA at a 4.5A CD calculates to a 93.75A setting with a peak voltage of 11.25V . If you are runniing LCD, then 30V will work.
SS

[anodizeme4ever]

What is your formula for calculating this?
Also, I want to increase current to 12 amps/sq ft

[sswee]

All my calculations are from the 720 rule and the results from Fibergeeks tests where he compared CD's, material types and other parameters. He measured the coating thicknesses with a current eddy meter to help verify his results.

If you plan on going to 12ASF, which is the highest with a 1:3 acid ratio, then I would try to go to a 40V supply. The calculation for peak voltage is CD x 2.5 . This is effected by several parameters and with an accurate SA will vary +-5V and I would add a extra 5V for possible miscalculation of SA.
SS

[anodizeme4ever]

So if I were to maintain a maximum current of 6 amps, would a 0-15 volt, 185 amp CC/CV rectifier do the job?
Where can I find Fibergeeks tests?
Thanks again.

[sswee]

0-15V will work, 0-18V would be better. Running that many amps in a tank will generate some heat, how are you planning to maintain the tank temp.?

I was lucky enough to start anodizing before Fibergeek passed away and talked to him on the forum quite a bit. His test results are scattered in the forum posts. You can run a search on posts by him to find the info he posted. I don't have a place where all the results are together.
These are his test graphs:
http://forum.caswellplating.com/phot...user/5846/sl/f

SS

[anodizeme4ever]

Going to have a 75 gallon rectangular tank inside a 140 gallon rectangular tank with ice water circulating around it. I have tried several methods and feel this is the best - works out to almost the same ratio of water to cool the anodizing. Also going with circulating pump for the acid to keep heat off parts.

[sswee]

I'm setting up a 60 gal tank now. I decided to go with a chiller unit. Let me know how it works. The pump for agitation will help alot. I've been using a pump for awhile. I like it much better than aeration.
SS