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DC Power Supply and plating


#1

Purchased a ‘used’ DC power supply… I am using a pen plater.
Plating gold on to silver. Not sure which terminal is the plus and
negative (no mark). Seem to do very poorly both ways ( trying each
terminal as the anode). Gold is dull, not ‘stuck tight’. Have clean
very well.

DC unit will only plate to 9 volts (although meter goes to 15,
understand that the unit doesn’t have to offer the 15) … when
plating at 9 (or any other voltage) volts, the amp meter does not
register, Is this usual???

Help!!!
Thanks,
Jim


#2

G’day

Purchased a 'used' DC power supply.. I am using a pen plater.
Plating gold on to silver. Not sure which terminal is the plus and
negative (no mark). 

What you need is a solution of an acid/alkali indicator, such as
litmus, even red cabbage or beetroot liquid would do. Add a pinch of
salt Epsom salt would be better - and place the two bare wires in
the liquid. The liquid around the negative wire will turn blue, and
it will stay red around the positive.

plating at 9 (or any other voltage) volts, the amp meter does
register, Is this usual???

The amount of current flowing - amps - in any circuit depends on the
total resistance of the circuit. If the power supply has an inbuilt
high resistance then it will not supply high current. The amount of
metal deposited from a plating solution per unit of time depends
upon amps times volts - watts, or work done in metal deposition; if
the wattage is low the deposit of metal will be low and poor.

Many DC power supply units are designed for use with electronic
devices which use very little power- current - and so the internal
resistance of the supply is high. Perhaps that is what you have.

Actually the easiest way to check the polarity is to use an external
meter, but you probably don’t have one. Another point is that your
plating solution may be old, or lacking in gold.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#3

Jim

I am not in any way shape or form and expert on plating by any
method, but I do know power supplies.

While polarity may not be marked, you can still tell the positive
from the negative. The terminals should be red and black, black is
the ground. In the absence of this, there may also be two posts close
together which will allow a strap to be placed across them. This
would be a floating supply, and would require that you place the
strap to the near post to set a polarity. In the absence of both of
these identification schemes, you may get a multimeter to determine
polarity of your supply. The next thing I would check on is current
from the supply, seems all of my reading on the issue of plating
requires a low voltage and significant current for plating to work
effectively. If your supply is not capable of putting out at least 1
amp of current, it may not work no matter what the voltage.

Terry


#4
While polarity may not be marked, you can still tell the positive
from the negative. The terminals should be red and black, black is
the ground. In the absence of this, there may also be two posts
close together which will allow a strap to be placed across them. 

I have a millimeter…but how would I tell the polarity when using
it???

Jim


#5

Hi John…

Good to hear from you…Hope all is well… Thanks for the advise on
polarity… I’ll get it a try… As to the gold… the gold solution
was very old… like 2 years but had never been opened…would that
make a difference???

Jim


#6

Jim

I am uncertain as to what you mean by millimeter, my answer was in
response to a used power supply a person had purchased. What is a
millimeter? (Please don’t say 1/10 of a centimeter) :slight_smile:

Terry