[luminous]

Any number from 3 to 6 is fine. The main advantage of the higher numbers is speed. To achieve a given coating thickness, a CD of 6 amps will only take half as long as a CD of 3 amps.
If you've got the time, there's nothing wrong with the lower CD. You should get similar results at either end of the range as long as you adjust the *time* accordingly.
According to the 720 rule, for a 1 mil coating a CD of 6A/SqFt gives 720 / 6 = 120 minutes. A CD of 3A/SqFt gives 720 / 3 = 240 minutes. For a coating thickness of 0.75mil you would use 3/4 of the time indicated by the 720 rule.

The main disadvantages of the higher CD's are:
1) In order to push a higher CD, the power supply also needs to have a higher maximum output voltage than is required with lower CD's.
With a CD of 4 amps/SqFt you can probably get away with a power supply that only does 12 volts max. But with a CD of 6A/SqFt you may need 15-16 volts or more to get the desired current. So the maximum VOLTAGE of the power supply limits your maximum CD, and the maximum CURRENT of the supply limits the maximum square footage of your work.

2) Higher CD's put more heat into the ano tank, so you may also need an improved tank cooling system to keep the temps in the "happy zone" and avoid dissolution problems.



steve