Hello Jim, I trust your sub is coming along nicely. I've been media blasting the interior of my sub of late. Who knew that could be so much fun. ;{ The more I do of that, the more I want a composite hull.
When you speak of emersion service, are you thinking more of long term emersion service? If some water did soak thru the coating the other standard types of coating should protect the metal as per usual, right? The guys at Rattleguard told me I could spray there product right onto bare media blasted steel that was to go in saltwater. I won't want to do that until I've done some long term testing on samples down the road. I think of the urethane coatings as more of a scratch resistant surface to protect the other coatings, as well as for insulation, noise reduction, eco reduction on the interior, and making the metal not cold to the touch and easy to hang onto, as in the case of my aluminum tubing conning tower guard.
The owners of the Rattleguard brand that I last used, told me they have there product strayed on concrete and composite ponds and pools all the time. I should go check out some of those projects after years of immersed service. There are supposed to be some steel fishing boats in the Seattle area that have had the bottoms of there hulls coated with a Rhino liner coating. I should go source them out, and see what they have to say, after years of sitting in saltwater. I know they like to spray there own paint type coating on prepped truck beds before they spray on the finish urethane coating as a type of bonder agent.
For now on the exterior I was just planning on using a urethane coating for the thruster tangle guards, conning tower guard, inflatable amas holding means and platforms, two small aluminum standing platforms next to the conning tower, and perhaps a couple other items. But not the exterior of the main hull. I was considering doing that on the next project however.
" The beginning of knowledge is the discovery of something we do not understand. " ~ Frank Herbert
Regards,Szybowski
Date: Thu, 2 Jul 2009 08:08:14 -0500
Subject: Re: [PSUBS-MAILIST] Urethane Coatings on Steel Ballest & Drop Weights
From:
kocpnt@tds.netTo:
personal_submersibles@psubs.org
Hi Brent,
I am not an expert, however I am an Industrial Painting Contractor.
I would like to use polyurethane because of it's resistance to chalking and fading, however my various paint reps all say that urethanes do not perform well in immersion service.
I used a zinc rich primer followed by two coats of high solids epoxy. These products can all be readily sprayed with the right equipment.
To have any chance of success, all polyurethanes should be sanded to remove gloss at a minimum and preferably removed altogether.
Best Regards,
Jim K
p.s. Spraying inside a sub really sucks!!!!
On Wed, Jul 1, 2009 at 10:19 PM, Brent Hartwig
<brenthartwig@hotmail.com> wrote:
Hi Frank,
I have loads of pictures now of all sorts of saltwater and freshwater boats that have been coated top and/or bottom with Rhine type urethane coatings with great results. Whether it be steel, composite, aluminum, or wooden boats. Besides most are subs live most there lives high and dry in the garage.
Those type of coatings can be strayed smooth if the application calls for it. I would be coating the whole outside of this KL-250 of mine if I wasn't painting it yellow. I don't know how well epoxy paints will adhere to the urethane type coatings. They have colors to choose from, but my personal experience tells me to stay away from the lighter colors, since they can get marked up easily and even in some cases obtaining a yellow tint after being in the sun awhile. With the steel being hot dipped galvanized, hot spray zinc coated, cold galvanized, high zinc epoxy, or the like that with a thick 1/8" to 3/16" urethane coating over your steel ballest and drops I suspect will do the trick.
A company in Missippi called Tyler Industries makes very large tub boat forklifts that have plain steel parts going into saltwater on a regular basis and they don't have to primer the metal. They do still need to respray the coating from damage from the boats. I've done a test and I can easily sand off the Rattle Guard brand urethane coating if the need arises.
The owners of the Rattle Guard brand of urethane coatings said that with there brand, all surfaces with 1/8" or more should be totally water tight from water coming in thru that urethane surface. I was thinking of just welding on some 316 SS tabs and/or bushings into drilled holes in the steel plates to connect them to the sub. Those SS parts can be coated as well.
I can't seem to get a straight answere from those that spray these type of coatings as to whether steel boats that are coated with these type of urethane coatings need anodes to protect the main hull of the boat or not. I would expect the urethane would be a good electrical insulator to prevent electrolisis if thick enough.
Regards,Szybowski
From:
ShellyDalg@aol.comDate: Wed, 24 Jun 2009 10:55:59 -0400
Subject: Re: [PSUBS-MAILIST] Recycling Lead
To:
personal_submersibles@psubs.org
Hi Brent. I wonder how useful that "plasti-dip" stuff would be on a saltwater boat. I may give it a try. As for lead versus steel, well, one of the great things about lead is it's so easy to melt and pour into specific shapes. My lead ballast will be poured into "bricks" that fit the curvature of the bottom of the hull. With nuts embedded in them so I can bolt them down. The drop weight lead will be poured into a steel "keel" with the drop socket mechanism also embedded in the lead. Remember that we need an extra drop weight just in case we have to drop one, and then use the spare to retrieve the first one. That adds up to a lot of lead!
Frank D.