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Originally Posted by XK120DHC
Peter;
Unlike most newbies,you seem to have a good grasp on the concept of plating.. That's a good thing..
On the Anode, you will be okay for small parts no larger than about 10 sq inches.. the USA Kits include two 4"x8" anodes, so depending on the size of the parts to be plated, you might think about getting a new pair of Zinc Anodes... just in case. (anodes get consumed, so they will be used eventually).
On the SD416, again, not knowing what the stuff is, I can only say we use a product called SP Degreaser that requires a "working temp" of 140F-200F degrees to "cook" the grease/dirt off the part.. Of course, follow the instructions that came in your kit, but you can "experiment" with some higher temps on old scrap to check-out the results (better, worse, no different, etc.)
You noted the Hanging Wire suffered the same problem as did the cast part, you are correct that this is a good indicator of what's happening, assuming that the wire is not lacquer coated (I ran into that problem, no plating current got to the part at all! Took me a while to figure that "glitch" out!). Of course it wouldn't hurt to insure the "Pos" and "Neg" cables from the Power Supply are connected correctly.. Hooking them uo backwards can ruin certain plating solutions.. I don't know if it will ruin the zinc solution, or not..
That just leaves the temp of the plating solution.. it has a working operating range that it needs to be in to plate effectively.. I assume your kit came with 300Watt Tank Heater and a thermostat of sorts .. if so, double check the solution's temp with a glass cooking "Candy Therometer" (and never use it for cooking, again!).. these are common over here, mostly used for making home-made candy, fudge, etc.
Another thing you need to add to "the business of plating" is some good/detailed records-keeping.. record things like: date, solution temp, if brightener was added or not, plating Start & End times, surface area of part being plated, amps per square inch (A/SI) used on that piece (and a "fixed" A/SI is NOT cast in stone, experiment with that, as well, until you find the one, or range, that works best for you), results of the plating.. i.e. pits, dull, inconsistant coverage, etc. This helps you to figure out what went wrong so you don't make the same mistake again.. Always strive to make new mistakes ;-}
Experiment on some scrap until you get the hang of zinc plating, then post back here to let us know how you did..
Regards.
Charles.
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I'm making some progress.
Having checked all the temps (using an infra-red non contact thermometer), I blasted, degreased, acid dipped etc a part - re-checked the surface area (e.g. current) as well and tried again
I also checked the wire wasn't laquered (with a continuity tester).
The part still came out covered in a dull grey (almost furry) layer, but blasting that revealed a zinc finish underneath.
So it is plating but I assume the part shouldn't really have the dull grey coating that needs mechanical removal (briefly dipping in acid solution isn't enough) afterwards.
Could that be from contamination of the solution?
Or is it simply a current issue?
I'm ruling out cleaning issues on the grounds that I've tried items that are pretty clean (blasting, degreaser, acid dipping - and also items fresh from being machined on my lathe), and problems would only really affect part of the item not the whole item.
I will certainly look into more anodes, as you say I will need them for larger parts, what I'm wondering is should I try a new plating solution as well
Thanks
Peter