Engine Enamel on Boat Hull?

I'm going to be repainting my aluminum boat exterior and interior (see link in my sig). I'd like to match the colors of my 1954 Mercury Mark 20 motor. From what I've seen Googling around, Dupli-Color DE1650 is a good match to the "Dull Aluminum" color, and Dupli-Color DE1644 is a good match to the "Mercury Green" color. It's just coincidence I guess that they are both Dupli-Color brand, and are both Engine Enamel with Ceramic on top of that. The only other good color matches I've seen suggested are from PPG, and I'm not ready to get into professional level painting. If properly applied, does anyone see a problem with using 'engine enamel with ceramic' spray paint on the hull of a boat? Says it's "Resistant to oil and other automotive fluids; will not blister, flake, crack or peel". It will be both above and below the waterline.

While I've never used engine enamel on a hull, I have used it on some valve covers. I used 3 light coats and 1 heavy coat on a properly prepped valve cover and it started blistering about 6 months in and flaking around 10 months in. Since a hull will never get as hot as a valve cover, I'm not sure how it would do. Just my experience with the stuff.

from what I have seen, people that have used the rattle can metallics
on large surfaces have streaks and inconsistent spray patterns.
The solid colors, green, white, blue, etc are okay.
But the composition of the metal flakes in a lacquer vehicle is the problem.
It's your boat - Your call.
Rattle cans are designed for patio furniture, small automotive projects,
and hobby stuff.
My only suggestion is to watch your spray pattern, keep a wet edge
and be VERY consistent to the distance and speed that you spray the paint.
If you are using Dupli-Color, I would use their suggested primer.
Read, understand and follow the directions on the label.

and the 'engine enamel with ceramic' will be fine. It just has a higher heat
and caustic chemical tolerance designed for motors than ordinary patio paint.





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Can relate to two things here.
A long time ago I sprayed a 1942 Ford Jeep with Cal Custom (I think) rattle can metal flake paint applied over a primer, and it came out pretty good.
I have rattle can sprayed the motor plus all parts, valve covers, brackets, radiator, etc., in my 66 Chevy quite a few times over the 50 years that I have owned it and the engine enamel seems to hold up reasonably well.
Don't know about using it on aluminum though, may need to prime it first.

I would steer clear of the Dupli Color stuff. I think it has to be baked on for it to last. Does ok for small engine parts and touch up type of work.

I would either roll on a better quality paint or use a real spray gun.

Do some digging around on this site there is a lot of good info on painting technique and selection. Prepping the hull is 90 percent of the job.