Re: [PSUBS-MAILIST] Paint.....Cheap or Proper?

On Mon, Mar 21, 2011 at 10:02 AM, Stewart Gardiner <stew@terminalsolutions.biz> wrote:

Thanks for clarifying that Jim! I did mean 2 part polyurethane…. Epoxy being a generic term for anything using a hardener etc J the particular paint brand ive used on fibreglass boats before is Norglass or Norcoat..

The polyurethane primer came out so well I was actually contemplating leaving it in primer and not worrying about the top coat! J but UV protection might not be so good with the primer…also its slightly porous…

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of JimToddPsub@aol.com
Sent: Tuesday, 22 March 2011 1:27 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Paint.....Cheap or Proper?

The last time I worked extensively with coatings was 1983. We were using two-part polyurethanes that cost $250 USD per gallon at that time. Epoxies were considered older technologies that were becoming obsolete, however I think the term "epoxy" is being used generically to denote any type of two-part coating (color and catalyst or hardener).

This is one of the last places I would try to save money, and I would spend just as much on interior primers and coatings as exterior for two reasons:

1. Preventing corrosion is a lot better than trying to cure it, and having to do that (and redo) the inside the sub can be a bear.

2. After an operation, I can wash down the exterior with fresh water and whatever else I chose to use. That's not an option with the interior.

I've also wondered about spraying the entire exterior with a wax several hours prior to a mission but haven't investigated that. Seems reasonable.

Jim

In a message dated 3/21/2011 8:15:34 A.M. Central Daylight Time, Alec.Smyth@compuware.com writes:

The first time I sandblasted and painted Snoopy, I put lots of coats of expensive epoxy on the outside, but had this same exact thought about the inside. That surely won't get wet, therefore cheap and ordinary paint should do! Well, when Snoopy was in Florida the humidity was 100%, the temperature was something ridiculous, and climbing in and out even splashed a little salt water inside. With the combination of those three factors, when I was being towed out to a dive site the inside rusted so fast I could actually see the rust move. I mean that literally, you could see it popping up from under the paint, rather like a paper towel that has been laid over a counter that's sprinkled with water.

I still don't use as expensive a paint on the inside as the outside, but one paint I've found is economical yet tough is a two part epoxy for painting garage floors. It's very thick, giving really good coverage, and resistant to abrasion. The downside is there aren't any rust preventers in it because it's intended for concrete, so you want to spray a base for metals underneath.

Best,

Alec

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From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of James Frankland
Sent: Monday, March 21, 2011 6:06 AM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Paint.....Cheap or Proper?

Hi All,

Im going to paint the inside of my battery pods today. As theoretically, the insides should not get wet, i was thinking of using just a normal metal paint like Hammerite or something. A straight forward paint that you would use to paint outdoor railings and things with. Do you think this will be ok or should i go for the "proper" 2 part epoxy marine primer? Its just really expensive.

What do you think?

Thanks

James