When I previously installed nonmetallic cutlass bearings in the old housings, I used a stainless steel
tube brush dipped in alumaprep and alodine to clean and prep the surface. Once that step was dry, I coated the inside and the bearing exterior with epoxy
barrier coat and slid the bearing inside. exactly as you described. This left a continuous epoxy
barrier coat all around the bearing that was continuous with the barrier coat on the hull
, struts, and bearing housings. I plan on using the same approach this time around, though I may add some colloidal silica to thicken the mix to improve its gap-filling abilities.
There are a couple of different corrosion
issues we aluminum
boat owners have to be concerned about. Zincs won't stop the more common oxidation corrosion
, which causes the white powder on aluminum
. I agree with you that grease won't be a very long-lived solution there. Epoxy barrier coat is definitely the way to go.