Short answer
Degrease the pin with an absorbent pen at 10 to 12V DC, plate a nickel underlayer at 5 to 6V wherever base copper shows, then brush 24K gold at 6 to 8V. A standard gold pen deposits about 0.5 µm in 2 minutes on a 1 in² area. All three pens, the power supply and cables come in the $400 Contact Repair Kit.
When brush plating is the right fix
Tank plating means removing the part, masking everything you do not want plated, and sending it to a plating line. For a handful of worn pins on a connector that is still installed, that is days of turnaround for a few square millimeters of gold.
Brush plating puts the solution in the tip of a pen. Metal deposits only where the tip touches, so you can restore one pin at a time at the bench or in the field. Electronics rework shops, aerospace MRO crews and avionics repair shops use this workflow on connector pins, edge connectors and switch contacts.
Why nickel goes under the gold
The gold pens plate over gold, nickel or silver. They do not go directly onto copper. If wear has exposed the copper base metal, you need a nickel layer first. Nickel plates directly over copper and acts as the diffusion barrier that keeps copper from migrating into the gold.
If the pin is brass or steel rather than copper, add one more step before the nickel: a copper flash with the Copper pen (PL-1010). If only the gold is worn thin and the nickel underneath is intact, you can clean and go straight to gold.
Step by step
- 01
Remove oxide and discoloration
If the surface is discolored or oxidized, polish it with a fine metal polish until the oxide is gone, then wipe it clean with a lint-free cloth.
- 02
Degrease at 10 to 12V
Set the supply to 10 to 12V and use the Absorbent / Degreaser pen (PL-1002). Connect the part to the negative (−) lead of the power supply and the pen to the positive (+) lead. Hold the pen so the whole tip touches the surface, and move it lightly back and forth in a slow stroke. Small bubbles form as oil and grease come off. Rinse with water when done. Stainless steel takes the Stainless Steel Degreaser pen (PL-1014) instead.
- 03
Copper flash, only on brass or steel
On non-copper pins, plate a thin copper layer with the Copper pen (PL-1010) at 6 to 8V so the nickel has a compatible base. Rinse. Skip this on copper pins.
- 04
Nickel underlayer at 5 to 6V
Plate nickel with the Nickel pen (PL-1006) over any exposed copper. A standard nickel pen lays down about 0.4 µm in 2 minutes on a 1 in² area. Rinse.
- 05
Plate 24K gold at 6 to 8V
Switch to the Gold 24K pen (PL-1003), set 6 to 8V, and stroke the pin until you have an even gold finish. About 0.5 µm in 2 minutes and 0.8 µm in 3 minutes on a 1 in² area.
- 06
Rinse and wipe
Rinse the part in water and wipe it with a soft cloth.
How much gold you can build
Standard pens reach a maximum of 1.5 to 1.8 µm. Heavy-duty pens carry more solution per cartridge and reach 3 to 3.6 µm, with the Gold Heavy pen depositing about 0.8 µm in 2 minutes. Each pen holds 10 ml of concentrated solution and covers roughly 300 square inches.
| Pen | 2 minutes | 3 minutes | Maximum |
|---|---|---|---|
| Gold 24K (PL-1003) | 0.5 µm | 0.8 µm | 1.5 to 1.8 µm |
| Gold 24K Heavy (PL-1016) | 0.8 µm | 1.2 µm | 3 to 3.6 µm |
| Nickel (PL-1006) | 0.4 µm | 0.6 µm | 1.5 to 1.8 µm |
| Nickel Heavy (PL-1020) | 0.8 µm | 1.2 µm | 3 to 3.6 µm |
Standard or heavy-duty kit
The Contact Repair Kit (PL-1000C, $400) includes the power supply, connector cables, and the Absorbent, Nickel and Gold 24K pens. Bought separately those parts come to $520.
For production-volume work such as switch-bank refurbishment or multi-pin connector repair, the Heavy Duty Contact Repair Kit (PL-1000CHD, $525) swaps in heavy-duty nickel and gold pens for thicker deposits and fewer cartridge changes.
Frequently asked questions
Can I gold plate directly onto copper connector pins?
No. The gold pens plate over gold, nickel or silver. Plate a nickel underlayer over the copper first, then the gold.
Do I have to remove the connector to re-plate it?
Usually not. Brush plating only deposits where the pen tip touches, so pins can be restored in place without pulling the assembly for tank plating.
What voltage do I use to gold plate a pin?
Degrease at 10 to 12V DC, plate nickel at 5 to 6V, and plate gold at 6 to 8V. The part goes on the negative lead and the pen on the positive lead.
How thick is brush-plated gold?
A standard 24K gold pen deposits about 0.5 µm in 2 minutes and 0.8 µm in 3 minutes on a 1 in² area, up to 1.5 to 1.8 µm. The heavy-duty gold pen reaches 3 to 3.6 µm.
Which gold should I use for electrical contacts?
24K. Pure gold gives the best conductivity and corrosion resistance for connector pins, edge connectors and switch contacts.
Not sure which pens your part needs?
Tell us the substrate and the finish you need. The people who build the system will tell you the sequence.