What voltage is needed to copper plate

A. Others on this site can hopefully supply the 'typical' voltage/current needed. As for using a welder, low cost (AC) arc welders supply in the 30 to 80 volt range. If you're handy, you could buy a cheap one and remove some of the secondary winding to give a lower voltage. It's directly proportional, to halve the voltage, remove half of the secondary. For plating you need DC, which means you need a rectifier. You'll lose a couple volts in the rectifier, so take that into account when modifying. For availability, try a replacement rectifier for a DC welder. You might also need a fan to keep the rectifier cool. I suggest this route of AC welder plus a rectifier because DC welders have an extra inductor (coil) in them that you don't need, thus driving up the price. It comes down to the local market as to which approach is more cost effective.

A. Glenn,

Electroplating depends on amps rather than voltage. You just need volts to drive the current across the resistance of the tank. The amps you need depends upon the surface area and the type of plating solution. I expect you will use an acid copper sulphate ⇦ this on eBay or Amazon [affil links] rather than the cyanide process but this gives poor adhesion on steel or diecast parts. (you can minimise this by putting the parts into the tank 'live'. The other problem you will have is the need for some 'brightener'. These are proprietary chemicals. A little goes a long way so any friendly plating shop will probably give you a little. A welding unit could potentially run a very large copper tank. A small battery charger ⇦ this on eBay or Amazon [affil links] would be more practical run at 6 v max. and some means of controlling and measuring the current would be useful. If you have limited control I would try about 2-3 v. A brown 'burned' deposit means probably too much current or no brightener. Give it a try & come back if you have problems. If you don't know how to handle acids then find out FIRST.

A. Hi Phoebe. We have written a presentation on amperage, voltage and Faraday's Law which I think you will find quite understandable regarding your interest in the process of molecular exchange and transfer.

After you have read it, you will realize that you need to know the surface area of the steel cable and the thickness of copper you desire in order to figure out how many ampere-hours you will need, but the volume of solution is not involved in the calculation (although it can be important in some ways).

Since you are presumably not in a hurry, you can simply use the low voltage Geoff suggested and plate for a long enough time to get the required ampere-hours; I think 8 volts will prove too much and will result in burning. But please also recognize, if you don't yet, that you need DC to electroplate; AC will de-plate as fast as you plate :-)

Regards,

A. Hi Phoebe

I agree with Ted, but have I spotted a problem?
Your question suggests that the cable is already nickel plated.
To get copper to adhere to nickel plating it must be done immediately (not in five minutes!). That is nickel plate - rinse - copper plate; and certainly not allowed to dry in between steps.
Any delay means that the nickel surface must be re-activated.

A. Yes, per Faraday's Law the thickness of the plating is directly proportional to the current flowing to that spot.

Regards,