Short answer
Polish off any rust, degrease at 10 to 12V DC, then stroke the zinc pen over the bare steel at 6 to 8V. Zinc plates directly onto steel and most other metals, except aluminum and chromium, at about 0.3 µm in 2 minutes on a 1 in² area. One $65 pen covers roughly 300 square inches.
Why zinc protects steel
Zinc is a sacrificial coating. Where zinc and steel sit together, the zinc corrodes first and the steel underneath is spared, which is why galvanizing works. Once a scratch or worn spot exposes the steel, that protection is gone at that spot.
The zinc pen electroplates real zinc metal onto the exposed area, so the repair works the same way as the original coating: it is a metal layer bonded to the part, not a coat of paint sitting on top of it.
Good jobs for a zinc pen
- Scratched or worn galvanized finishes
- Exposed steel fasteners that have lost their zinc
- Zinc surfaces that have lost their protective layer over time
- Field repairs where dipping the whole part is not an option
Step by step
- 01
Remove rust and oxide
Polish the area with a fine metal polish until the rust and discoloration are gone and bright metal shows. Wipe it clean with a lint-free cloth. Zinc will not bond over rust.
- 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
Plate zinc at 6 to 8V
Set the supply to 6 to 8V and switch to the Zinc pen (PL-1013). 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. Overlap slightly onto the surrounding zinc so the repair blends into the existing coating.
- 04
Build up with more passes
The zinc pen deposits about 0.3 µm in 2 minutes and 0.5 µm in 3 minutes on a 1 in² area, up to a maximum of 1.5 to 1.8 µm. Keep working the spot to build thickness.
- 05
Rinse and wipe
Rinse the part in water and wipe it dry with a soft cloth.
What it will and will not do
The zinc pen builds up to 1.5 to 1.8 µm, which is far thinner than a galvanizing line puts down. It is a touch-up and spot-repair tool for damaged areas, not a way to galvanize whole parts. For new parts that need a full coating, send them to a galvanizer.
Zinc plates over any metallic surface except aluminum and chromium. The Micro-Metallizer system does not work on aluminum.
What you need
The Zinc pen ($65), the Absorbent / Degreaser pen ($65), the power supply ($220) and connector cables ($20): $370 in all. If you already own a Micro-Metallizer supply, or any variable DC supply up to 12V at 0.1A, the two pens are $130.
Frequently asked questions
Can you zinc plate steel without a tank?
Yes. A zinc plating pen holds the solution in its tip and plates only where it touches, so you can re-zinc a scratch or a fastener in place at 6 to 8V DC.
Can I use a zinc pen on rusty steel?
Remove the rust first. Polish the area to bright metal and degrease it, then plate. Zinc will not bond over rust.
How thick is zinc from a plating pen?
About 0.3 µm in 2 minutes and 0.5 µm in 3 minutes on a 1 in² area, up to 1.5 to 1.8 µm. That suits touch-up and repair, not full galvanizing.
Can you zinc plate aluminum with a pen?
No. Zinc plates over any metal except aluminum and chromium, and the Micro-Metallizer system does not work on aluminum.
How much area does one zinc pen cover?
Each pen holds 10 ml of concentrated solution and plates roughly 300 square inches.
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.