Painting aluminum?

[Andris Golts]

Hi all im putting together a electric outboard and considering painting the K&B lower unit gloss black to match the MRP motor cowl. I have never painted aluminum before. What is required for preparation and what kind of primer and paint is needed for this kind of job ? Or is painting the lower unit a bad idea ? I would like the finish to be durable and not scratch going through a weed patch or hitting a floating twig or the paint to bubble. Regards Andris Golts.

[CraigP]

Sounds like powder coating would be your best finish. If you are set on paint, a good quality epoxy paint would be durable. The units need all finish stripped first, then primer paint. The paint you choose will have specific application instructions. I would clear coat it too for added durability.

[Old School]

Aluminium will require an etch primer to ensure the topcoats adhere to the surface. The surface will need a lot of preparation prior painting. I would Google what actions are required before attempting this. In the aircraft industry the aluminium was anodised firstly (chemical treatment) then a zinc chromate primer applied then topcoats. The anodising ensured adhesion with the overcoats. Personally, I would not paint it as long term the paint will not be durable. Powder coating as suggested may be an alternative.

[MadProps]

paint is easily removable and is also sandable to feather edge out a chip or scratch for repaint or touchup
I have not used powder coat, how easy or difficult will it be to deal with chips & scratches etc in powder coat?

[JestDanny]

I've got two outboard's using K&B 3.5cc lowers. The biggest prop you can run is a X442, the fastest prop is the P-215, that's how it works out on my tunnels. I like to use the O/B engine cowling from the mini F-3 O/B sold here at OSE 10$. My 3S boat runs mid 30's the 4S boat mid 40's and honestly when those boats cruse by under full throttle lookin so kool, the lower unit is the last thing you'll notice. When they get older they get dull gray even less noticeable.

[Andris Golts]

Thanks to all for the information provided . Regards Andris Golts.

[785boats]

Automotive paints work well, but as suggested, an etch primer first.

[TRUCKPULL]

If you go to a Marine store
They sell or can get Black Mercury out board primer, paint, and clear in rattle cans.

Larry

[RaisedByWolves]

This is what you want.

Not cheap, but its a good proven durable product that bakes on.


https://www.brownells.com/gunsmith-t...-prod1150.aspx

[MadProps]

This is what you want.

Not cheap, but its a good proven durable product that bakes on.


https://www.brownells.com/gunsmith-t...-prod1150.aspx

agreed I refinish my used guns with this and it wont chip or scratch off you will have to scratch all the way to the aluminum

[Andris Golts]

Thanks to all for even more painting options. Larry i just remembered i should have a can of the Mercury primer and there Phantom black paint sitting in the boat house as i did some touch up paint work on the skeg of my Optimax last fall . Regards Andris Golts.

[JestDanny]

Ok so what hull are you going to put the nice shiny black scale mini Mercury K&B outboard on? Do tell what you're building. I heart O/B's.

[Andris Golts]

Hi JestDanny the outboard is going to be mounted on my 22'' Stark tunnel GP-12V3 thats the second generation John Starks designed tunnel hull . Regards Andris Golts.