if it was me, I would get a (fused) varible transformer( variac), and a step down transformer (voltage output you desire, and a little excess wattage or VA), (secondary windings of transformers can be modified as secondary coil is outside winding). A large rectifier bridge (Higher amperage capacity double good ), or use four diodes to make your own bridge rectifier. A large electrolytic capacitor (polarized with large microfarad,double the voltage minimum), a large ceramic varible potientiometer (resistor), (another option make your own).
alot of these materials can be scrapped from old equiptment.
The primary for variac, is the source for power( AC power input), the secondary of variac is wired to the primary of your stepdown transformer, the secondary of the stepdown transformer is wired to the AC terminals of your diode bridge rectifier(~), the positive of diode bridge rectifier go's to positive of your capacitor, and is also the anode lead to your electrolytic plating cell, the negative of the diode bridge rectifier go's to the negative of your electrolytic capacitor, which is also the negative lead to your electrolytic plating cell,
the variac will control voltage output, it is a transformer you control the voltage output with a knob on the transformer (tv repair men use them), (old lighting Flourecent dimmers was variacs).
the varible resistor is wired in series with the positive lead to electroplating cell controlls the amperage to your cell, A light bulb can work in its place of varible resistor (potentiometer), and has the advantage of not only limiting current but also being an indicator as to what amperage cell is pulling from load and if cell is shorted lamp protects your power supply from burning up,by just lighting bright.
another option for varible resistor a piece of ceramic wrapped with stainless steel (wire feed welding wire) and tapped for current desiered, this and any resistor limits current by dissapating heat, and this will need to be mounted in air away from shorts or anything flammable, it will basically be like an electric heater, in fact electric heaters also male great resistors, but I am getting off of subject here.
all wireing needs to be able to sized for the curent within the circuit,
amperage meter can be added as well as voltmeter,
power supply's are very easy to build, they are in almost everything;
they can also be scavanged from other equiptment, there are different type's of power supply's for different applications, but they all fall into similar catagorys.and follow certian principles.
there are also other ways you can put together a plating cell power supply.
Example 6 volt battery charger able to handle amperage you require, plugged into a variac, which plugs into ac outlet.
P.S the term rectifier for the power supply is an old term , that kindof confuses me somewhat when you are asking about a power supply, as when I say rectifier it means diode or to change from AC to DC, platers may use this terminology, similar to how in mechanics we use the term condenser in your vehicle (points and condenser) condenser is an old term for capacitor, and with vehicles we still call them condensers not capacitors,
I can not help if you just want to buy one, but if you decide to build I can.
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I haven't done much with zinc except for electroless, but I have plated copper, tin, chromium, silver, gold and rhodium commercially. If you monitor it at the start of the run, you should be all right. The reason you have to watch it at first is that initially you have a battery consisting of the zinc anode and the base metal with the solution for an electrolyte, aiding or bucking the applied voltage. As soon as a significant layer of plating builds up, it becomes a battery with both electrodes the same material, so it contributes zero volts to the circuit. That usually happens quickly and after that the current will be fairly stable. I never used a resistor in the circuit. Zinc should not be especially sensitive to ripple so your filtering should be adequate. Chromium, for example, is sensitive to ripple and really doesn't like it.
Most of the time is is a good idea to "go in live", turning the power on before dropping the part in the solution. The reason is that sometimes there will be an adverse reaction between the base metal and the solution. Sometimes it deposits metal electrolessly with a poor bond. Plating properly over it doesn't help. You do need to get the whole part immersed quickly so the initial current density will be correct over the entire surface. You may have a problem with your capacitor charging to the peak value of the AC causing a surge.
I don't know what the market is there, but around St. Louis used regulated supplies are common. They usually are both voltage and current controlled and often can be found for less than the cost of the components.
Bill
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