DayTripper

I have a stainless rail down the center of my bow/deck. I'm repainting the boat and wanted to paint the rail to match the deck. Is this acceptable? What type of prep is needed?

I'm using PPG DP sealer for the rest of the boat.

Thanks for your help,

DayTripper

James

Stainless steel loves to be painted. Dull the surface by blast cleaning using 120 g aluminum oxide or use # 220/ 320 sand paper to etch the surfaces and provide a profile. Prime with epoxy primer and paint -

If you are going to powder coat prep the surface the same way

Downtown42

I prefer metal-lock paint by dupont for S.S...same stuff truckers paint their alum. fuel tanks with SS straps.

Regular paint will not hold up as well with future chips and niks.

I had my rails done and it is more durable than powder coat or paint.

johnnyboatman

how about spraying with bulldog adhesive promoter.

James

Adhesion promoter are often silanes or vinyl wash type primers, both go on very thin at .5 mils are ph adjusted to be acidic. These materials are designed for OEM sheet goods where it is often cost prohibitive to sand or other wise prep the surface. Think of the SS rail like a piece of glass - Spray paint the windshield of your car - two days later remove the paint with a simple scraper - Sandblast the windshield of your car two days later you can not remove the paint. With profile on the surface you have more surface area or grip.
One test for paint performance is an adhesion test. A dolly is glued to the paint then pulled vertically away from the surface - the resistance is measured in psi - when the dolly breaks from the surface you have your value - assuming the paint breaks before the glue - here is a quick table of values, test and numbers have been rounded and have surface prep based on normal service conditions.

1. Adhesion promoters silane & vinyl wash 250 psi
2. Automotive primer Dupont # 615 variprime 600 psi
3 Paint on the hood of your car 750 psi
4. 3m 5200 FC on fiberglass 2000 psi
5. Polyamide epoxy 1,800 psi
6. Polyester Powder coat 1,800 psi
7. Novolac epoxy 2,100 psi
8. Paint on an army tank 1,200 psi
9. Paint on a 747 850 psi
10. latex paint 100 psi
11. Rustoleum alkyd paint 200 psi

The value of adhesion promoters is low, however it is much better than application of say higher value epoxy to the same surface. Even the epoxy has trouble gripping to a smooth surfaces and the value of epoxy on the same smooth surface may actually be lower than with an adhesion promoter. However with surface prep, adhesion promoter then epoxy the test will alwasy fail at the interface between adesion promoter and epoxy.

For the SS rail - rough up, blast, sand , prime with polyamide epoxy and top coat with aliphatic polyurethane and you will have a value that is higher than the "automotive" becuase you have a better prepared surface. Powder coat will always have high values on blasted surfaces, and the same powder on a smooth surface will have 1/2 the values.

Gmoney52

Don't get too confused with the maxium adhesion unless the rail will be abused by being tied and docked. What is paramount is dulling the surface and that is best accomplished by blasting (especially long and multitude of rails) as James suggests, but I use #80 then #180 before primer. Paint will be best color-match, powder coat more durable and don't get taken with powder paint! (not durable and fades). Not familiar wither Dupont metal-lock, but it sounds promising. G$