Questions on 720 rule and rectifier

[hvacman250]

1. I was planning on buying Caswell's 20 Amp Constant Current Rectifier , but they have been back-ordered for awhile. Any Caswell people know when this will be back in stock, or where I can buy something along the same lines?

2. I'm still confused by the 720 rule and how to apply it. ( I am using a 10 amp, 15 V DC power supply. There is an adjustment knob that I believe increases voltage; thtas it. If I turn it up, the voltage and amps go up)

Example: 190 total sq in / 144 = 1.32 sq ft
Target current density at 6
1.32 x 6 = 7.92 amps to the parts

I had my PS full blast, and it was drawing about 5 amps. Thats all I could get out of it. I ran at 2 hours (5xxx and 6xxx parts) and the dye took great (deep red).

But, I'm guessing I don't have a full 1 mil build. Is that so bad?

If I do 720 rule: 720/5 amps (pulling)= 144, 144 x 1.32 sq.' = 190 min in the tank

So I only did built a .66 mil because I did 2 hrs instead of 3?

[acidrain]

Yes, you have it correct.
Your amps may be low because of a couple of factors:
Acid/water ratio will affect resistance.
Tank temperature will affect resistance.
15 volt PS may not be enough to run 6 amps per sq. ft.
Ano thickness will affect color. You'll want to ano to a full 1mil for black and other dark colors. .75mil is fine for medium colors, and .5mil for gold and clear.
GL