Safer electroplating solution 4
I have been wanting to try a zinc anode with this solution. I did manage some successful plating of zinc with the old, tainted TSP, so this should be a breeze with the good TSP.
Experiment 1: Steel parallel as a target; cleaned with AJAX and stainless steel wool. Area estimate 2 in^2
09:17 : start. T=51C; 0.2A
09:30 : Looks like a nice coating looking though the glass vessel
09:58 : stop; t=58C;
Result: Uniform, matte gray coating. The grinding marks are still visible. SS wool cannot remove the coating.
After letting it sit with a little water on top I see a lot of rust. Apparently no plating occurred, but just an etch of the surface. :(
Experiment 2: Use existing bath to try and coat a brass rod. Area ~ 2.5 in^2. Current 0.2A
10:14 : start; T=56C
10:31 : no sign of deposition
10:59 : no sign of deposition; solution becoming turbid
11:11 : T= 54C; increasing current to 0.86A, at which point I am voltage limited to 31.6V
11:21 : current is up to 1A. No longer voltage limited. There is some plating visible towards the bottom of the rod and on the side towards the anode.
12:12 : T=60C; stop;
Result: Light gray coat. Brass seems to shine though a bit, so the coat is very thin. But it is strongly adherent.
Experiment 3: use same plating bath on SS spoon
12:34 : start; T=50C; 1A
12:54 : stop; no sign of deposit.
Experiment 4: Same bath on steel parallel again. This time higher current, since it took a long time to deposit anything on brass.
17:42 : start; 1.0A T=34C
19:47 : stop; T= 53C
Result: Black on one side. The other area looks like a contour map. gray to black.
Letting water sit on it again yields rust. No plating was achieved.
Experiment 5: Try to plate onto copper. The target is a small coin. Current 0.1A
09:18 : start; T=23C
09:33 : stop; looks like we plated something.
Result: There is a better looking deposit towards the surface of the solution. A scratch test shows that there is copper below the deposit, so we did not just remove the copper.
Experiment 6: Try to plate another coin with lower current of 0.05A
15:17 : start; T=24C
15:57 : stop; no sign of deposit. remove coin.
19:00 : continue; T=23C
20:35 : stop; T=55C; no clear sign of deposit; maybe very light. remove coin.
08:26 : continue; T=23C
12:05 : stop.
Result: Dark gray coating on penny, but I tried to polish it with Brasso, which took it right off. That may have been ill-advised.
Summary: It seems to be quite difficult to deposit zinc with this solution. Back when I worked with the tainted solution, I managed to quite easily first copper plate a stainless steel spoon and then put a tick coating of zinc onto that. It is surprising that with the good solution it seems harder, so that merits another look in the future.
Finally, the zinc anode got badly corroded even though hardly any zinc was deposited.