How to paint my drive

[woodworker2001]

I struggled with painting my outdrive with the Mercruiser paint. I bought a ton of it in rattle cans and it would blister and pit every year. I thought my anodes weren't working and I went so far as to change the type and considered testing the corrosion protection system. Turns out the outdrive manual advises against using the rattle can spray paint. Below is the refinishing procedure recommended by Mercruiser. I striped my outdrive down to shiny bare aluminum and painted with this system a few years ago and it has stood up well. My boat sits in the water for at least 5 months and it doesn't corrode.
Refinishing procedure:

This procedure should be used in refinishing MerCruiser sterndrives and transom plates. This procedure will provide the most durable paint system available in the field. The listed materials should be purchased from a local DITZLER AUTOMOTIVE finish supply outlet. The minimum packaged quantity of each material shown is sufficient to refinish several sterndrives and transom assemblies.

1 QT. DX-533 Alumiprep #33 metal preparation
1 QT. DX-503 Alodine #1201 conversion coating
1 QT. DP-40 Non sanding Epoxy Primer zinc chromate primer
1 QT. DP-401 Catalyst for DP-40
1 QT. DAR-9000 Acrylic Enamel-black topcoat
1 Pt. DXR-80 Delthane Ultra-additive for acrylic enamel
1 QT. DTR-602 Acrylic Enamel Reducer-temperature range 70-90 degree F.

PROCEDURE:

1. Scuff sand to remove all blistered paint and roughen factory finish. Remove sanding dust.
2. Follow manufacturer's recommendations and instructions on the individual containers.
3. Apply DX-533 (Alumiprep #33) to clean and condition the aluminum.
4. Apply DX-503 (Alodine #1201) brush on chemical conversion coating for aluminum.
5. The DP-40 (Epoxy Chromate Primer) mixed with DP-401 Catalyst can now be applied. A .75 mil film build is recommended.
NOTE: Allow 30 minute induction period for permeation of the epoxy chromate primer and the catalyst prior to application.
6. The topcoat consists of DAR-9000 Acrylic Enamel Black and the DXR-80 Delthane Ultra additive, and DTR-602 Reducer. It is a polyurethane acrylic enamel system which provides fast drying, durability, high resistance to corrosion and good color and gloss retention.
7. The type of spray gun used will determine the proper reduction ratio IMPORTANT: DO NOT use any type of aerosol spray paints, as the paint will not properly adhere to the surface, nor will the coating be sufficiently thick to resist future paint blistering.
NOTE: DO NOT PAINT SACRIFICIAL ANODES.

Evinrude Boater How did you strip your outdrive down to bare metal? How hard was the transom plate, gimbal ring while still on the boat?

 

[Scott Danforth]

that is a direct copy from the Mercruiser manual on paint.

 

[Evinrude Boater]

woodworker2001 I used a wire cup on an angle grinder to strip the paint. Also used sand paper on the tight spots. It still looks good today.

 

[Bt Doctur]

DO NOT USE A STEEL WIRE WHEEL
brass, bronze or stainless steel .Using a regular steel wheel leaves microscopic particles of steel in the aluminum

 

[wca_tim]

you can do very well with 180 or 220 grit sandpaper on a da followed by epoxy primer and good single stage urethane... That's held up very well for me on several drives...

 

[Bondo]

DO NOT USE A STEEL WIRE WHEEL
brass, bronze or stainless steel .Using a regular steel wheel leaves microscopic particles of steel in the aluminum

Ayuh,.... Even more important when weldin' the aluminum, ssteel bushes only,....

As for paintin,....
Never strip off ole paint that's firmly attached to the base metal,....
Just sand, prime, 'n paint,....

After you've dealt with the corroded areas 1st,....

Myself,.... every few years I brush the crud off the drive, 'n shoot it with a rattlecan of Rustoleum industrial enamel,...