I need to set a number of threaded bars into cement, to hold a new gatepost. When I cut the bar into shorter pieces, the metal near the cut became red hot, presumably hot enough to evaporate some or all of the zinc with which the entire rod was plated.
Now I want to plate zinc back onto the ends, and have had mixed success so far. I dissolved some zinc oxide with hydrochloric acid and hooked it up to a little PV panel I have, and after a while it seems there is a light-coloured deposit on the cathode. The pencil-lead (6B) anode is no longer as smooth as it first was, but it doesn't seem to be losing (much) of its bulk. I assume it to be zinc, because... well what else can it be? It plated thick enough that I had to (ab)use a nut to re-cut the thread, leaving a light-coloured shiny surface that gives me more confidence that it is, in fact, zinc.
Problem: the edges of the threads seem to be taking more zinc than the valleys. In some cases the thread's valley doesn't show any evidence of plating. The fractal-like deposit on the edges is quite pretty actually, pity I can't take a (good) closeup photo.
Is there anything I can do (perhaps using some other common(ish) kitchen chemicals?) that will result in a more uniform layer of zinc? Is it worth trying lower / higher current or pulsed current? Am I overthinking things - is it even necessary for the whole stud to have a layer of zinc?
