Interior Steel Hull Paint

[jonahmcg]

I've recently bought a 35' steel ketch, it's a self build. The original builder blasted and epoxy coated the interior, it's in very good condition, just a few bits of rust at some seams and 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.

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.

[ausnp84]

Originally Posted by jonahmcg

I've recently bought a 35' steel ketch, it's a self build. The original builder blasted and epoxy coated the interior, it's in very good condition, just a few bits of rust at some seams and 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.

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.

Seems odd that no-one's replied yet (given all the steel boat expertise on this forum) but hey ho, here goes...

1.) If the two part epoxy is in great condition, leave it as is and just fix up the areas that are rusting. Cut them right back to bare steel (depending how extensive, a wire brush on a grinder will do the job), then prepare them in a similar fashion to the original. Any reason for covering the interior paint with white - bearing in mind you'll need to overcoat it with insulation anyway?

2.) Not having a huge experience with poured concrete, as long as it's airtight, the steel beneath will be ok. The problem will be in any areas where water may have seeped beneath the concrete or there are any cracks. Have a good look for this - that'll be your problem areas. If there aren't any - great!

n

[Tory Salvia]

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[Duder]

jonahmcg,

I'm doing my 2nd refit on my steel girl as well. In 2003 I debated some of the same questions concerning the epoxy coated interior. I suspected the coating had been applied during a 1993 major refit and internal redesign but had never been painted nicely in open area's not covered by insulation & wood. I used a rust guard acid treatment on all areas I found. Then used a pointed welding hammer and steel brush to pop away any affected areas. There are epoxy steel filler products that adhere & harden nicely but I personally prefer the old fashion way of weld filling, grinding back then treating small pits. I cleaned, lightly sanded, cleaned again with acetone then used a 2 pack enamel primer. Sanded lightly (again the acetone) then 2 coats white 2 pack enamel paint. Sounds like overkill but the older epoxy coating (I suspect was blown on) wasn't smooth and I was looking for a smooth, easy to wipe down clean surface. My theory is; the easier you can make a surface to clean, the less likely it is to hold any surface substrates that might cause corrosion. The 2 pack is a challenge both inside and out with necessary respirator, ventilation... but I've found the advantage to a hardener bound enamel paint to be valuable long term.

On the Bilge / Keel area; If you find a minor weathering crack in the concrete, I wouldn't give it much worry. But, if you see obvious areas where water has been allowed into or around larger cracks or the sealed keel area appears to have been violated by moisture that might have crept into the sealed area. My preference here again is both 2 pack primer then 2 pack paint for a reliable seal. Concrete floor paints are fine in a garage but the marine demands bend the rules greatly.
I would (and have) drilled a small (plastic straw size) hole in the lowest keel area from the outside. If you strike water, just let it drain nicely. I left it open a few days, made sure I used a straw to keep the hole clear then closed with a weld. I didn't get more than about 20 seconds of water but the good feeling of knowing I've cleared it out and resealed it solid has lasted me 12 years!
I hope some of this is useful ~ Best wishes & fair winds.
Duder
S/Y Windana

[hpeer]

Something I would consider using on the top of a concrete bilge section is a polysulfide caulk like Boat Life. Or, what may be cheaper is a 2 part sealer such as FlameMaster 3204. You can get in a self leveling consistency. It's impervious to diesel.

I would do that no matter what. Getting water in the ballast section sucks.