steel interior hull paint question

[jonahmcg]

I've recently bought a 35' steel ketch, it's a self build. The original builder blasted and 2 part epoxy coated the interior, it's in very good condition, just a few bits of rust at some seams and minor stuff down where concrete was poured into the bilge. We'd like to cover the interior paint in white -- I've two questions.

1. What type of paint (system) makes sense to overcoat the two part epoxy that was initially sprayed on? (and should i use a different paint for the small bits of rust and then overcoat everything, or is there a product that would work to just do another whole layer. (i was thinking interprotect by international.)

2. The ballast/bilge is rough concrete with some steel and some random lead chunks laying about, i'm wondering about sealing the concrete and overpainting with something (like floorpaint?) and do i need to worry about rust in the area the concrete is poured.

any thoughts would be appreciated. Will obviously scrap back rust as much as possible etc.

[haiqu]

With a two-pack finish, I'd give it a good clean to see if it's still serviceable before considering repainting. If you decide to repaint you'll need to take out any visible rust and prime those areas, then apply another two-pack to the whole interior. Follow the manufacturer's recommendations regarding surface preparation. If you don't want to strip out the whole interior for spraying it could be done with a brush but only prepare small batches as it "goes off" fairly quickly.

You don't really need to worry about minor surface rust in the ballast area, but if that bothers you then you could apply a sealer like Altex Altra-Lock then repaint down there. I've had excellent results with it when sealing reinforcement bars before applying new cement to repair missing chunks on the exterior of a ferro, no more rusty streaks on the hull at all.

[Pauls]

Concrete is a rust preventative for steel. You shouldn't need to be concerned about the steel under the concrete, unless you have saltwater in the bilge frequently. If you do then I'd go with a concrete sealer.

As Haiqu said, rust areas should be cleaned up thoroughly and repainted. Pick a paint manufacturer (I'd recommend PPG), talk to a tech specialist for the factory and use what he recommends, and follow the prep recommendations religiously.

As an aside, because the paint is internal, sheltered from UV and the ocean, and you are not relying on it to protect the steel but just to change the color to white, I think you have a broad range of choices open to you, from 2 part poly down to good grade gloss house paint. This is not a critical application. The protective paint layers needed to protect the steel ARE critical, and should be the best you can deliver. This is just a top coat.