DP and Norm,
Credit and thanks to you gentlemen for the progress I made yesterday. And, I’m afraid, shame and disgrace on myself. Norm your comment that something was clearly wrong – and DP, your observation that my parts looked burned lead me to investigate my power supply.
Yes, there was a problem. I found that current was fluctuating from 0 to 3.6 amps. Obviously the cause of recent poor results. Last week, I had it ‘dialed in’ at .9 amps and since my bolts and batches have been roughly the same size, it seemed to be working fine. I left the settings alone and only turned on the power switch. Something went awry. I’m embarrassed!
I got this ‘Dr Meter’ power supply through Amazon before I started plating. Dialing up current or voltage has always been a bit finicky. Turn a knob just slightly and it hunts up and down the scale before settling. If you have a suggestion for something better, I’d probably replace it.
NOW THE GOOD NEWS!!
Once I identified the power problem, I had some success with the black chromate. It’s not great, but we’re moving in the right direction.
Suphuric Acid!
DP, I started experimenting with sulphuric acid for the initial bath; based on your advice. Yesterday I tried your method of giving the part an acid dip between zinc ‘stikes’ and before chromating. I think this made a big difference. Thanks!
Norm, All my chemistry is from Caswell, including two batches of zinc solution. I’ve gotten great results with it. I’ve also gotten equal results with the homebrew. Going forward I’ll probably standardize on all Caswell, just to be consistent. Thanks for all your help!
