Metal paint

[Charlie]

I looked at my windlass the other day and the motor cover was completely rusted. The gear box was in decent shape but the cover for the motor was bad. I took the gear box and motor off of the boat and am having the motor worked on. When I get it back it will need to be repainted. The parts sit in the anchor locker and as such are exposed to moisture (surprise on a boat) so I wanted to know what type of paint would cover the metal surfaces best. I was thinking an epoxy paint would be best does anyone have any reccomendations on brands and/or whether epoxy paint is the right way to go?

[Sunspot Baby]

If you can strip it and clean it well, go to a powder coater and have it finished. This puts a plastic coat on it with good adhesion.

90% of a successful paint job of any type is cleaning and surface preparation.

On the cheap end I have had good luck with spraying with Rust-O-leum (spelling?) or similar products.

[Charlie]

Thanks George:

I can't powder coat it b/c the heat would destroy some of the components. I want to find a step down from pwder coting or powder coating w/o heat.

[Sunspot Baby]

Sorry, I thought you would pull the cover, stripped of components and refinish that. Didn't realize that they are an inseparable assembly.

The rest of the advice holds. Cleaning and surface prep are key to a good paint job.

George

[Alan Wheeler]

There are two methods of painting.
Clean as best you can. Then use a Zinc rich primer and then there top coat. You can buy coloured Zinc rich top coats now as well from CRC.
Or you can etch prime using PA10 or Wattyl paints etch primer and then use a single pot epoxy or enamel paint over top.
Or you can go to the Hammerite coating system. They say you don't have to use a primer, but I suggest you do use it in a marine environment. Hammerite is not an ordinary paint. It is fast drying and has glass flake in it and the result is a very fast drying finish that cures to a rock hard surface. There are two versions of their product. Hammered surface which is good for covering not so smooth pieces and the smooth finish.

[over40pirate]

Speaking of rust. Has anyone had any experience with POR-15 rust preventing paint? In a salt environment, I have found it's impossible to keep steel parts from rusting. Maybe POR-15 might work.

[hellosailor]

I'd second the zinc primer, multiple coats of silver metallic zinc paint, which stops galvanic problems. If you really wanted to go deluxe--you could send it out and have it triple nickel or chrome plated, no heat trapped that way either.

[Alan Wheeler]

I have seen the POR-15 advertised on TV here in NZ as a "Infomercial". And like all Infomercials, I dismissed it as yet another piece of rubbish. But I have not used it, or even seen it, so it could well be as good as advertised. But I find it hard to believe that someone can hammer the finish on steel with a large hammer and not even place a mark on it.

[Wotname]

For the record, powder coating is porous and therefore not so good in a marine enviroment (unless the process has improved markedly in the last 5 years); I second the zinc rich primer and single pack epoxy enamel top coats.

[cooper]

I second and raise the above....go with a two pack epoxy of an industrial type.

zinc paint, which stops galvanic problems.

if only it was true.....

If you take the logical reason of zinc...it is as a sacrificial metal. ( more noble) It helps but it dont cure. It IS a good idea but does not replace anodes. Zinc prime (epoxy based) epoxy primary top coat (perhaps aluminium solids) polyurethane (2 part) top coat....

[cooper]

second thought...is the motor cover cast steel or fabricated? Most windlass bits that I know of are aluminium or bronze. Can you get a cover fabricate of SS?

[sildene]

Originally Posted by over40pirate

Speaking of rust. Has anyone had any experience with POR-15 rust preventing paint? In a salt environment, I have found it's impossible to keep steel parts from rusting. Maybe POR-15 might work.

I've used POR-15 paint on a gearbox, engine mounts and other parts. So far so good (12 months). I bought it after being somewhat impressed by the distributor's antics - he struck a metal rod painted with glossy black POR-15 with a hammer right in front of my nose, then bent it 90deg, and it didn't crack or chip. But, you wouldn't know whether he prepared and painted his sample via 'special' preparation or not (probably).

Disadvantage: The paint hardens with moisture, so once opened, it tends to have limited shelf life (mine was lost after 5 months on shelf).
You need proprietary preparation, unless the metal surface is in ideal condition for the paint.
Also, when you paint cast iron, you have to make absolutely certain that the metal (and any pores) is bone dry, else it comes off.

According to the distributor, the manufacturer approves it for use up to 250F, which should mean it can be used in the engine bay of a small yacht.

(No, I won't hammer my gearbox to see how it stands up.)

Martin

[S/V Antares]

POR-15 is a great product as are many others however surface prep is 99% of the game. Most anything will work if the prep is well done. Any leftover grease will spoil the pudding. After several rounds of degreasing using aggressive solvents and superclean wipers sand the surface to provide "Footing" for the primer and paint system. Use cheap disposible cotton gloves when handling the cleaned metal as a single fingerprint can cause a failure of the coating and water will wick under the paint.

Take your time and allow primer and final coats to dry

[Charlie]

Thanks for the advice. I guess I'll go with the two coats of zinc primer and then a two part epoxy paint. I want a coating that will last a long time. The less often I have to do this the better. Oh yeah prep work will be important. I' think I'll strip it down to the raw metal.

[hellosailor]

Charlie, also consider that epoxies are routinely 'filled' to modify their performance. Mixing in zinc or copper flakes, or powder, will enhance the heat transfer through the epoxy coating. Sort of the industrial version of the "MetalFlake" paint that looks so good on show cars.<G>