Boat Forum / Building / November 2005

What size is it?

I used such for the ten years I lived aboard my sail boat...100 gallon
tank in the forepeak just aft of the chain locker.

Made of 3/4 ply glued with Resorcinol and also bronze screwed to 3/4 x
3/4" hardwood strips along each seam on the interior.  Interior was
coated with a couple of coats of Gluvit as was the lid interior.  Lid
was then glued & screwed to the rest.  For a vent I used a small (3/4"?)
check valve on a plumbing "U" so that as water was pumped from the tank
the check valve opened from air pressure.  Though I didn't, the check
valve could be filtered.

Nowadays, I'd probably forego the Resorcinol, screws and Gluvit and just
use epoxy fillets to join and coat the interior with same.  Depending on
tank size and how well it was braced from the exterior, thinner ply
would be fine too.

Obviously, it wasn't meant to be cleaned.  Never felt a need.  If you
insist on being able to open it up to clean, one way would be to put
closed cell foam slightly proud on the top edges of all sides, add
hardwood strips around the outside of all top edges, then bolt the lid
to those strips thereby compressing the foam.

As far as making an odd shape goes, one measures the space then figures
the size of the 6 parts necessary to make a box to fit therein.

--
dadiOH
____________________________

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I made the holding tank and ice box for my old 32' Traveler by first fabbing
a mock up with cardboard, (you can make a lot of adjustments/mistakes with
cardboard for free!)
Once I had the shape I wanted, I took the cardboard parts and used them for
patterns for 1/4 exterior fir plywood. I then laid 2 or three layers of fg
cloth/epoxy on the inside surfaces of the plywood pieces before assembly
with bronze ring nails. I then filleted (epoxy and low density filler) and
taped the fillets  (cloth and epoxy). I installed deck plates on the holding
tank for clean out.
For the ice box, I placed a pan of boiling water inside and closed the lid
and left until the water cooled. As I remember this was to harden the epoxy
and keep odors down. Something like that anyway, sounded like a good idea
and I never noticed any (odors).
I got that from "This Old Boat" (I think) which is a great book for anyone
wanting to work on their own boat.
MMC

Search this group for the thread 'water tank coatings' from a few years
ago.   The most salient point you may discover is that you *should not*
use "regular" epoxy - the amines may leach over time, with a potential
for unhealthy side effects.

MW

Kevin, unless you're planning a very large tank, it might be almost as
cheap and a LOT easer to drop in a plastic tank. Check the Ronco
Plastics catalog http://www.ronco-plastics.com They make top quality
tanks for a very reasonable price, and have more than 400 shapes and
sizes to choose from, over 100 of which are non-rectangular.

Alternatively, there's a company in ME called Triple M Plastics who
makes custom welded plastic (PP) tanks for a very reasonable price. I
don't have any personal experience with 'em, but several people on a
couple of the email lists I'm on have bought tanks from 'em and are very
pleased with both the price and quality. They don't seem to have a
working website...I was able to pull a phone number:  (207)985-4705
Fax: (207)985-8012

Just a couple of suggestions...

Yes you can make a F/G epoxy tank.

Make sure you finish the interior of the tank wity a couple of coats of
"tank resin" which is a resin approved for tank coatings.

Seal the lid to the tank with SikaFlex 291.

Good luck.

Lew

Lew