sealing wood from salt water

[maldivian_chicken]

I moved house recently, unfortunately none of the SPS survived
the few weeks in a small tank with neglect while I was getting ready for the move, but that's another
story. After moving the stand to the new house, I noticed
that the vertical panels (painted particle board) were swollen
from years of moisture, so it was a diasaster waiting to happen
with the 100gallon sitting on top of it.

I plan to replace the panels with just a sheet of 3/4" plywood,
not marine grade plywood, but just regular home depot
plywood. I need to seal the wood with some kind of waterproof
paint, but wasn't able to find any oil-based paint at homedepot,
OSH, or my local Kelly-Moore.

Where can I get waterproof paint that can tolerate salt water
for the inevitable spills of the sump once in a while? Failing
that, can I use marine spar polyurethane (assuming several
coats) to seal the wood?

thanks

[sfsuphysics]

Yah, I think the big home improvement places are moving away from oil based anything, and more towards latex ones. What I would do is use a thompson weather seal or similar good deck coating on it, unsure if you can get oil based here either.. might have to shop at another smaller store to find it, something about oil being evil *sigh*.

Of course unsure how that'll work with paint, but I'm guessing the insides are what got all messed up due to the moisture from a sump or refugium in the stand? Or from actual spilling? If its evaporative moisture from the sump, then its not saltwater that's making everything wet, so your weather sealer should be fine for the inside, then just paint the exterior whatever color suits yah, use exterior paint and you should be fine.

Now if its saltwater that's getting all over it, more so than the occasional wet arm that comes out or what not, then I would highly recommend trying to make sure it doesn't leak at all rather than sealing the wood to protect it from leaks :) If its some sort of overflowing issue that might occasionally happen I wouldn't worry that much about it, just make sure when you clean up the spill that occur make sure everything is dry, and get a good desktop fan or something, those things work wonders for drying up spills, use a mop/towel to get the majority of water then aim a fan on it (or oscillate if its all over the place) and that works better than you think at drying out all the pieces of whatever.

[maldivian_chicken]

I think the moisture came from salt spray where the tank
drains to the sump. There must have been a couple pounds
of salt crust at the bottom of the stand after I took the sump
out. This was from about seven years of accumulation.

I think the crusty salt made what water spilled in there
difficult to dry because it was so salty.

I plan to seal the wood with either oil based paint (sounds
like people who build plywood tanks use epoxy paint) if
I can find it, otherwise marine spa polyurethane, followed
by silicone caulking of all the seams.

Do you think that will do it?

[lrsafari]

Probably more work than youwant to go to, but ou seal it up with fibreglass. You could even color the resin or even put a "lip" around the floor and run the fibreglass mat and resin up the sides. 1 extra level of protection against overflow if you made the resulting "bowl" watertight.

Of course, you might want to do this outside! Not sure what the effects of breathing the stuff in an exclosed space might be.

Just an idea.

Scott

[RonSF]

You can either go the marine route by buying paint from West Marine or another boat supply place or you can go the professional paint store alkyd, or epoxy based deck paint route. I'd probably use the epoxy based deck paint (Murallo is one brand) due to toxicity issues if you have livestock still around. I'd lean toward boat paint if you have a respirator and want the absolute toughest finish. If you are in SF you can go to a place like Fregosi, California Paint or really most any store that sells to contractors, and find several products that will work.

Personally, I'm using a catalized lacquer on my stand in progress, but I also have a spray booth and lots of spray gear. It would be a disaster if you tried to use that material in your house without the right equipment. I'm upgrading from a P.O.S. 72 gal. AGA tank stand to one that I have built myself in a black lacquer and cherry finish. All I have to do is get a couple of days off here and there . . . .:(

[hammerhead]

I used thompsons water seal when I made my stand.

3 coats of water seal
3 coats of stain
3 coats of polyerathane.

[raddogz]

I love marine spar varnish! I used it inside of my canopy and then painted white over it. I also used it for inside my stand as well. If you aren't going for pretty on the inside you can use shower pan liner or pond liner to line the bottom of the stand.

[amgbenzs]

maldivian_chicken-
I have some wood sealer and brush. Its yours if you want it. Its new, never got the chance to use it.

[mcox33]

I use exterior (sp) latex enamel from lowes 3 coats of undercoat for enamel and 3 coats of paint. So far 18 months and no damage but I constantly manage to spill water in my cabinet. once it is under the sump forget it, it just has to dry on it's own, so far no problems.

[omzz]

Marine polyerathane all the way.

[jimsar]

I used polyurethane, 4 coats. Spills and moisture in general are unavoidable especially if you have a sump inside the cabinet, and I'm glad I took the time to moistureproof it.

If I were to do it again, I'd probably go with 2-part epoxy paint carried by West Marine. I can't remember exactly how many, but the label says it's equivalent to "?" coats of polyurethane. Anyway, it's up there, something like 10 or 12.

Jim

[sfsuphysics]

Jim how much does that epoxy paint run for though? I know that is an option for plywood tanks, but from what I gather its not the cheapest thing in the world, something like $100 per gallon or something? (of course I might be thinking of something else).

[jimsar]

Originally posted by sfsuphysics
Jim how much does that epoxy paint run for though? I know that is an option for plywood tanks, but from what I gather its not the cheapest thing in the world, something like $100 per gallon or something? (of course I might be thinking of something else).

You're right, Mike, it's pretty expensive especially if picked up from West Marine. However, HD sometimes carries it at a much lower price. You've got to search for it, though, because it's not a common item. I wonder if garage floor epoxy coat will work; it's a lot cheaper.

Jim

[capescuba]

Fibreglass is the ultimate IMO - my custom made stand/canopy are finished with this and it's just like glass :D

Then, just to be 110% sure, my sumnp area is lined with Pond Liner - pricey stuff. but I have already made use of it several times :rolleyes:

[sfsuphysics]

And how expensive is coating the inside with fiberglass as opposed to other options? I've never seen fiberglass resin at any of the popular one-stop home improvement stores.

[Qwiv]

You can also use a piece of sheet vinyl and make a pan inside your sump. Roll up the (4) sides and caulk the corners.

Super cheap.

[jimsar]

Originally posted by Qwiv
You can also use a piece of sheet vinyl and make a pan inside your sump. Roll up the (4) sides and caulk the corners.

Super cheap.

Good idea ... until water gets between the vinyl and the wood. Happens all the time in bathrooms, hopefully we won't splash around the sump. :)

[prodman]

Latex paint will be more than sufficent. Water based paints hold up extremly well to all kinds of conditions. And most if not all plywood these days comes standard with exterior glue. You wont have the problems you had with the particle board.

[Qwiv]

make a coved base with the vinyl and caulk the corners

[capescuba]

Originally posted by sfsuphysics
And how expensive is coating the inside with fiberglass as opposed to other options? I've never seen fiberglass resin at any of the popular one-stop home improvement stores.

Who knows - it was custom made. All I know is that I don't have to worry about splashes here and there, even the odd "minor flood" is no big deal.

[maldivian_chicken]

Over the weekend I replaced the particle board with 3/4" plywood, and painted
the outside with just normal interior latex paint I have around
(I just painted the bedrooms before moving in, so have tons of left
over paint).

The interior I haven't yet touched. I was getting a quart
of marine spar varnish at homedepot when I noticed that
they sell a two-part epoxy pour-on, so I picked that up
instead. Will see how that goes.

The biggest change this time will be not having all the
electrical outlets under the stand, seeing how things
have rusted last time. I'll get all the power cords outside the stand (I counted 12 plugs),
but may have to eventually build an auxillary stand to house the
electrical connections, CO2 bottle, makeup water, ..etc.

Some one suggested a pond liner/shower pan. Previously
I used some leftover swimming pool solar blanket, I think
that was the cause of the problem. Salt crust and water
somehow seeped between the stand wall and the liner and ended
up underneath the liner, and therefore couldn't dry.
So no liner this time so that any damp will be visible and I
can take corrective action.

/tom

[jimsar]

Tom, let us know how the two-part epoxy comes out. Ease of use, finish, etc.

Jim

[crazzyreefer]

west system epoxy, I make 500-100 gal ply wood tanks from it, no leaks, no fiberglass, roll it on and in 1 hr its dry, if you laminate two peices of wood togeather the stongest part will be the joint, west system can be bought at west marine, do not use varnish or thopmson water seal, back in the early 80s Texas A&M dod a study on it and fond the key ingredient to cause cancer, in fear of goverment intervention and law suits they removed the ingerdient, but never found a subsutute that came even close to protecting wood, so now you have to retreat every 6 months, what a waste of time.

[mikeo1210]

Shower pan liner works well for lining stands maybe after you paint it. I agree latex is fine. Be sure to primer.

[maldivian_chicken]

Him,

The 2 part epoxy from homedepot worked out quite well.
The instruction said 1 quart should cover 9 square feet
to 1/16" thickness. I don't need it to be so thick, but
needed to cover about 18 square feet inside the stand.

I mixed in several batches using an 8oz plastic cup. It
was easy to mix, not too foul smelling, and quite easy
to spread. It took a long time to cure though. I did
one side of the stand, then flipped the stand 90 degrees
to do the other side. The 2nd side came out quite well,
but the first side showed a lot of runs from resting vertically
before curing.

To do it perfectly I should have let the first side cure for
at least half a day to a day before doing the other side.

Overall I only used not much over a pint of the stuff to
cover 18sf with a fairly thin coating but it should be quite
moisture proof if not water proof.

The smell lingered in the house for a day, so it'd be best
to do it outdoors. Cure time was about half a day to tacky but
not runny, one day to feel soft but not tacky.

/tom