OK, I have finished the 4 etchings using the sampler image.  I did not replicate any of the conditions so, yes I know, I may just be looking at variation and not a real signal to draw a conclusion.  However I am getting a lot of advice to be kind and gentle with the current and that electrodes close is better than far away. The results certainly reinforce that recommendation.

 

Plate 2  -etched depth 3 mil  -5v   -.25 amps  -electrode distance 2.0”  -rating 1

 

A rating of 10 being the best and a rating of 1 being the worst for etch quality.

 

Now, I am also being told that I really need to be focusing on amps and not voltage.  I really do not understand the laws but I do understand changing levels and changing variables and measuring responses. If I stopped right now, I would put my electrodes close together and run 1 volt instead of 5.  I guess I could experiment  with a range of voltages below 1 and keep the distance constant.  Or maybe I should be exploring the design space of reducing the distance to below 2 inches.  This could go on forever.  

 

If I didn’t know that I could vary current then I might be tempted to run another 2 level 2 factor experiment like distance at 2 and .5 inches and voltage at .5 and 1.

 

I am tempted  to jump off and vary the current and let voltage float.  That would suggest holding the distance to 2 inches and setting amperage to a range from

.05 to  .5.  From my experience so far, I know that if I drop amperage for my standard target then voltage will also drop. Since I believe that lower voltage is better for some reason at a fixed amperage and knowing that etch depth is a function of current density and time, then exploring amperage seems to be the thing to do.   Since, a lower amperage is going to drop voltage that seems to be a good thing.  Of course  reducing amperage is going to reduce the amount of etching so I guess I would need to also increase the time of etch to evaluate plates at a constant etch depth.  Huh?  

 

Or.......

 

OK ,one of you saavy statisticians who also kinda’ know this process , please make a suggestion for my next experiment. =)