The authoritative public forum
  for Metal Finishing since 1989
-----

Brush plating a hole

I wish to brush plate the INTERIOR diameter of a hole which is about 1/4 inch in diameter and about one inch long. The walls of the hole are german silver and I wish to plate about .001 or .002 inch of nickel over the whole length of the one inch hole. I am told that I can not plate a depth that is deeper than the diameter. This would mean that I could plate no more than a 1/4 inch of the one inch hole depth. First question is; Is it true that the depth of plating is no more than the diameter of the hole? Second question is; if the depth of plating is limited do you have any other solutions.

Jerry Cadwell
consulting engineer - Shoreham, New York
2000

Re: Your 1/4" diameter vs depth of plate allowance; I think you have bath plating, or flame spraying confused with brush plating.

Re: Substrate; Are you plating a solid silver substrate, or just applying Ni over plated Ag? There could be repercussions to a plated Ag when you clean/activate it prior to brush plating the Ni.

Re: Brush Plating a hole. Yes you can - if your anode is long enough, and preferably a rotating anode.

Noel Gibilaro
- New Britain, Connecticut
2000

---

To Jerry Cadwell:

The CVD process (chemical vapour deposition) can do nickel coating inside tubes, for pieces such as the one you describe. We have applied a nickel coating of 1 micron or less (in fact, we can go up to 1 inch if needed!) of pure nickel to the inside diameter of tubes. One example of successful nickel coating was on 1 inch long ceramic tubes with an internal diameter of 330 microns. We put a uniform coating of nickel 0.3microns inside the length of these tubes.

The CVD process is not by line-of-sight, and nickel can therefore be deposited inside tubes, or deep cavities, or inside closed cans.

Sincerely

Mick O'Meara
- Toronto, Canada
2000

---

Jerry,

Depositing nickel into a 1/4 inch x 1 inch hole is no problem. The brush plating process can easily plate this part with .001-.002 in. of nickel, provided the proper processing steps are followed.

Chris Helwig
- Valencia, California
2000