Electroless nickel plating inside blind holes

A. 1st, 2 microns of EN is not enough to "prevent" rust.
2nd, it requires an extreme amount of rack manipulation to get even some of the blind holes to plate. If the parts are not too big and too heavy, you may have better luck plating them in a barrel with heavy air agitation under the barrel.

Unfortunately, the part design did not consider plating.

A. To start with, ask your supplier to add a wetter to the solution.

Another solution which maybe less practical is to take out the parts from the EN every 3-5 minutes, tap on the rack and return it to the solution

A. Another reason can be insufficient degreasing or pretreatment of the pieces. If you do not rinse the pieces well enough, it can happen that the holes will not receive the right amount of ENP.

A wetting agent is very easy to make, so there is no need to buy such a thing.

A. Hi, Laban.

A wetter solution is a surfactant that reduces surface tension. One such chemical is sodium lauryl sulphate. Wetter is not so much something you add to improve coverage in holes, as something you maintain for good plating. But one of the ways it may assist in plating in holes is by removing clinging hydrogen bubbles.

Regards,