reelfishin
Captain
- Joined
- Mar 19, 2007
- Messages
- 3,047
Re: self etching primer vs zinc chromate
When ever I need to paint or repaint a lower unit, motor, or any aluminum I use Duplicolor Self Etching primer on any bare aluminum.
I sand down the old paint, prime any bare areas with the Duplicolor SE primer, scuff, and paint with the final color. I've done whole boats, lower units, and complete motors with good results.
There is nothing wrong with the Rustoleum brand paints, they even make a marine grade enamels. For the most part I use MAB RustOlastic, which is very similar to Rustoleum, I just have a better source for MAB.
Don't attempt to spray self etching primer over any existing paint as it will lift or etch the old paint. Its solely meant for bare metal. I lightly scuff the primer with a Scotchbrite pad and wipe with a tack cloth. Then paint.
The ticket to getting good adhesion is to be 100% everything is clean.
Do a search for water break test. If you wet the surface to be painted and water rolls off or beads, it's not clean enough. Water should 'wet' the surface to be painted, not run off.
This is 90% of the battle to getting paint to adhere properly. If the surface is not clean, no paint will adhere properly.
When it comes to Black or White paint, I've actually had good luck with the $1.00 per can paint at Walmart. I first found out how stubborn that stuff is to remove at work after trying to strip it off of an aluminum transmission case. The customer painted the trans all black, dirt and all. Even the high pressure high temp parts washer didn't phase it. For whatever reason, that paint adheres very well even to bare aluminum. I think in part its due to how thin it is and it may be actually soaking into the metal like a dye. I painted my 40hp Mercury with it about two years ago, the motor was showing it's green primer so I figured anything was better than no paint at all and I went to town with two cans of Walmart black enamel. It still looks good 2 years later.
When ever I need to paint or repaint a lower unit, motor, or any aluminum I use Duplicolor Self Etching primer on any bare aluminum.
I sand down the old paint, prime any bare areas with the Duplicolor SE primer, scuff, and paint with the final color. I've done whole boats, lower units, and complete motors with good results.
There is nothing wrong with the Rustoleum brand paints, they even make a marine grade enamels. For the most part I use MAB RustOlastic, which is very similar to Rustoleum, I just have a better source for MAB.
Don't attempt to spray self etching primer over any existing paint as it will lift or etch the old paint. Its solely meant for bare metal. I lightly scuff the primer with a Scotchbrite pad and wipe with a tack cloth. Then paint.
The ticket to getting good adhesion is to be 100% everything is clean.
Do a search for water break test. If you wet the surface to be painted and water rolls off or beads, it's not clean enough. Water should 'wet' the surface to be painted, not run off.
This is 90% of the battle to getting paint to adhere properly. If the surface is not clean, no paint will adhere properly.
When it comes to Black or White paint, I've actually had good luck with the $1.00 per can paint at Walmart. I first found out how stubborn that stuff is to remove at work after trying to strip it off of an aluminum transmission case. The customer painted the trans all black, dirt and all. Even the high pressure high temp parts washer didn't phase it. For whatever reason, that paint adheres very well even to bare aluminum. I think in part its due to how thin it is and it may be actually soaking into the metal like a dye. I painted my 40hp Mercury with it about two years ago, the motor was showing it's green primer so I figured anything was better than no paint at all and I went to town with two cans of Walmart black enamel. It still looks good 2 years later.
