Refinishing the lower units

[Mike sandor]

I just got my boat home from Lake Ozark. Prior to picking it up, the marina
acid washed both lower units. The prior owner did not keep up with the anodes and there is a fair amount of corosion, paint bubbled off. I started with a pnuematic right angle grinder with a scotch brite pad. It made quick work of removing the paint but i am concerned with the pitting. I plan on filling the pits, have been told to use two part epoxy but not sold on that idea just yet. Do I need to prep prior to filling? I would expect that there is some material down in the pits, and concerned that it may attack the filler material. Is bead blasting necessary or is there some liquid prep that is would work prior to filling and painting. The boat is going to be slipped in fresh water.

 

[bbwhitejr]

Someone else will chime in hopefully, but I remember a thread here that discussed some sort of etching for the aluminum before paint or anything. Mine on our 260DA was not as bad as yours sounds, but I did have some paint bubbling. Between a wire brush, scotchbrite pad, and various grits of sandpaper, I removed the bubbling paint down to the metal, wiped it good with acetone, primed it with several coats of primer, and top coated with numerous coats of Mercruiser Phantom Black. It turned out like new. We kept the boat and ran it for another 2 years and it was as good then as the day I painted it.

Bennett

 

[paulswagelock]

You should not use a wire brush or any steel based abrasive on aluminum.
Alodine is the best prep for bare aluminum.

A self etching primer is a must, zinc chromate works for this application.

 

[Loyd Dinneen]

I would start replacing zincs if you have not already done that and for sure dont use steel base brushes as they can become enbedded in the aluminum and rust.

 

[mjoplin]

Paulswagelock is spot on! Alodine and Zinc Chromate primer