Power supply

[aalamo]

Hello,
In page 18 of the manual (power source section), there is a diagram of a simple set up of a power supply that suggests the use of a 6-volt battery, bulbs or rheostat, an ammeter, and a voltmeter. I want to build my power supply following that diagram. However, since electronics is not my background, I would like to have some help here. FYI, I want to use the rheostat instead of the bulbs, and I will be doing only copper plating (specifically flash copper). What specification should the elements of the diagram (rheostat, ammeter, voltmeter, and battery) should meet? And, once built how does it operate? What should I look for when reading the meters? I am very new at this so please any help would be greatly appreciated.
Thank you
Alfredo Alamo

[Fibergeek]

The first thing is to establish how much surface area you want to plate at a time (how large is your largest part). This will determine the current that the power supply will need to be capable of. Flash copper requires 9 Amps per square foot of surface area. You could also state this as 62.5 mA per square inch of surface area.

As an example:
Say that the largest piece you intend to plate is less than 48 square inches. This requires 3 Amps (144 / 48 = 3) The voltage required for electroplating is low, never over 6 Volts. In the case of copper I doubt if its over 2 volts.

So, how large is your work?

[aalamo]

Fibergeek,
Thank you for answering. The largest piece is never going to be bigger than 60 sq". However, how do you calculate square inches when the piece is three dimensional? But in any case, my pieces will never be more that 12” tall, 5” wide, and 5” deep.
Thank you
Alfredo

[gsw3]

Just buy one!

Alfredo, not to disappoint you, however, by the time you buy all the stuff you need to build the power supply, you will have spent at about $165.00
(unless you may already have some of the items).

Analog Volt Meter: $15.00 - $20.00
Analog Amp Meter: $15.00 - $20.00
Rheostat (large wire wound type) $35.00 (could be more however)
6V high capacity GellCell $40.00 - $60.00
Battery Charger (if you do not have one) $25.00 - $35.00
Enclosure for meters and rheostat: $15.00
Plus your time and frustration factor (looking for/buying all the items).

Also, you will not have the fine control when doing small items because of the resolution of the Analog meters (usually on the $15.00 type meters they are 0-12Vdc and 0-10Amps). Kind of hard to read 1.75V @ 100Ma. on those type meters.

In other words, buy the Caswell 20A CC/CV power supply ($300.00) and you will have everything you need.

Over the many years of my life I have found that sometimes the old "I'll just make it myself" is not an economic and smart choice.

Just my .02

George W.

[gsw3]

Assuming the piece was solid (or a closed welded sheet metal box) using your 5 " x 5" x 12" example:

Bottom: 5 x 5 = 25 sq in.
Top: 5 x 5 = 25 sq. in.
One side: 5 x 12 = 60 sq. in (times (4) sides = 240 sq. in.)

So the total would be 290 sq. in.

Don't forget if you are plating sheet metal to figure both sides of the metal sheet!

George W.

[dadkar2]

AAlamo,

I agree 1000% with George. Please do not get caught in the trap of thinking you can design a power supply for less than you can buy one. I am in the electronics industry and it is my full-time job to design instrumentation products, including power supplies. I would STILL buy one even though I could draw out a schematic and parts list in about 10 minutes. In my present plating shop, I have two which I purchased. It's just NOT economical to do it--nor worth the time.

If you've never done it before, you will sink a ton of time into it and may never have a supply that works anywhere near as well as Caswell's.

Given what you're trying to do, don't mess with light bulbs and batteries. Just buy the power supply. You will be thankful to have a "stake in the ground" and one less variable to deal with when something in the process doesn't work later.

Capital equipment should be thought of as a depreciating expense. From a financial point of view, don't think of it as a big one-time expense. It really "amortizes" over the life of the equipment. A power supply will last 10 years. That is $30/year, or less than $2.50 per month. You'll pay more than that for protective gloves that you throw away.

Kind regards,
Ken