Painting Lower Unit--What to use?

[studlymandingo]

Well, I created some more work for myself. I recently traded a couple of boats for an 18' Center Console with a 150 Mariner OB. The Fiberglass Clamshell was sun-damaged pretty badly to where there were glass strands sticking out on top. I had originally decided that I would do a light sanding, shoot it with some spray cans and call it a day. Now, after 4 primer and filler layers, and 5 coats of storm gray shot through the HVLP, (wet sanded between each coat of course), then topcoated with a clear urethane; the clamshell looks probably smoother than it did out of the factory. Now I realize that what I have done, is created more work for myself. The bottom of the outboard motor looks like crap, the paint is faded and worn through on the skeg. Of course I can't leave it like that now, not with that shiny clamshell sitting on top. My question is, what is the best paint to use on the lower unit? It is of course aluminum, and I want to make sure that what I put on will stick. I would also like to use the boat pretty quickly after it is painted. What is the best type of paint to accomplish my goal? This is probably going to cause me to have to do other cosmetic upgrades to the rest of the boat...It never ends!

 

[jch7450]

Re: Painting Lower Unit--What to use?

is it going to be left in salt water the whole season?

 

[studlymandingo]

Re: Painting Lower Unit--What to use?

not left in, trailered, but in saltwater several times per week.

 

[studlymandingo]

Re: Painting Lower Unit--What to use?

I want to make it look good, but I run the boat at top speed in saltwater quite frequently and I don't want to have it peeling after a few runs.

 

[Pony]

Re: Painting Lower Unit--What to use?

IMHO, I'd use some TEMPO Marine Outboard paint. In my restoration I used automotive paint (because Tempo didnt make the color I wanted........BUT your mercury "Black" should be VERY plentiful) <br /><br />As for making the paint stick..........you are going to have to etch the aluminum, since it oxidizes as soon as it contacts air. What I did (Paul Moir suggested it), was take spray bottle and make a 50/50 solution of white vinegar and water. Much easier than my original plan of using a toothbrush in the solution. After sanding the old paint and primer away, I sprayed the solution on the Lower unit and let it air dry in the sun..........immediately thereafter painted it with Zinc Chromate Outboard Primer. That Primer is also made from Tempo. It s a lille more expensive (like $10 a can), but it really doesnt take much to cover the area. It should say on the primer can how long to wait before painting (ie how long of a wait requires sanding first)

 

[Paul Moir]

Re: Painting Lower Unit--What to use?

Sand down the bare or corroded spots until you find shiny metal. Scuff the paint. The factory paint has a far better grip on the aluminium than you'll be able to achive so try to preserve it. Wipe down everything with acetone.<br />Spray the bare spots with a mixture of 50% vinegar and 50% water. Allow that to dry - it'll etch & convert the aluminium. Rinse it off with water and do one last final wipe down with acetone. Then prime the bare spots with zinc chromate, or if that's not available zinc phosphate primer. Observe the warnings on the can because especially zinc chromate has nasty health consequences.<br />Then you can use glazing putty for scratches, high build primer and wet sanding until you get the surface you want. Do not use Bondo, if you've got large areas to fill you're going to need to use a filled epoxy. Topcoat with a good enamel or even better a 2-part urethane.<br /><br />That's always worked well for me. Even my half-arsed jobs seem to hold up well.<br /><br />EDIT: Looks like you beat me to it P.O.N.Y! Studlymandingo, have a look at the link at the bottom of his post, and you can see how it's done.

 

[studlymandingo]

Re: Painting Lower Unit--What to use?

Great!! Thanks guys for the help. I'll be prepping the aluminum tomorrow. I'll post some pics of how it's coming and how it turns out!

 

[studlymandingo]

Re: Painting Lower Unit--What to use?

<br /><br />Here's the cowl sitting in the sun drying the clearcoat. It'll get a 1500 grit sanding and 1 more coat of clear.

 

[surlyjoe]

Re: Painting Lower Unit--What to use?

NICE!!