Painting Nickel Plated Parts

Q. We manufacture parts that are plated with nickel and would like to know if you have any suggestions for a primer for nickel-plated steel? We would like this in both water- and solvent-based systems. –D.S.

A. Although difficult, coating nickel-plated parts can be done, but you must first follow a few preparation basics. I do not know what grade of nickel you are wanting to coat, but as a general rule, you will still want to first clean the plated metal with a water-based degreaser, along with a scotch-brite pad, or a heavy duty sponge. Next, thoroughly rinse the degreaser off with wet rags and completely dry the entire surface. If you have an oven, it would be a good to place the parts in for 15-20 minutes at 120°F. Once parts are completely dried and cooled, use a good quality painter’s tape to mask off any area you do not want to be painted. (Cheap tape with poor adhesion often blows off while you’re spraying.) Next, there are many options when it comes to primers in both solvent and waterborne systems. But as a general rule, here are a few recommendations:

You will want to use a primer system like a galvanizing metal etching product. Typically before the nickel plating will accept paint, it requires some form of a pretreatment/acidic primer, formulated with the ability to etch durable metallic surfaces applied after the initial cleaning. This is referred to as mechanical etching. After the primer has sufficiently dried, follow the manufacturer’s recommendations as to the sanding preparation that needs to be done before the final enamel topcoat. I have also heard of people using solutions of 30 g/L of sodium or potassium dichromate at 85°C for a minute, which will sufficiently etch the surface for painting. If you incorporate this etching process, completely rinse and dry the surface before any coating application.

Lastly, with both the primer and final enamel, spray with the manufacturer’s recommendations and close attention to application parameters, noting that improper mil application can actually promote flaking.