 Check out the bookstore at IRBS.com |
|
|
|
|||||
|
||||||
From: Tom (no email)
Date: Sun Oct 01 2006 - 13:15:53 EDT
At 11:30 PM 9/30/2006, wrote:
>I need to build a new holding tank. Ideally, I'd use a plastic one. it's
>a custom shape, though, so that isn't an option. So, the question is, what
>material should it be?
>
>Aluminum isn't even remotely an option. The original aluminum ones didn't
>last but a few years. The aluminum replacement I made didn't last much
>longer. Fiberglass isn't a good option, as I lined the replacement with
>fiberglass and it didn't hold up well.
>
>So, is stainless a good choice? I have no experience to rely on, but I
>doubt it. How about monel? (Did I spell that right?) Is Monel something
>I can weld with my TIG? Never worked with it.
>
>Other suggestions?
>
>Gene Gruender
Lew posted some good advice, but I would go one step further.
Mock up your tank using expanded polystyrene foam. The blue foam rigid
insulation by Dow found in home improvement stores like Lowes and Home
Depot. I cut this with a "hot wire cutter" (Google is your friend :) ) but
it is also easily cut with a serrated bread knife.
Using layers of this foam tacked together with foam-safe adhesive. Then by
carefully carving the foam away, you can literally 'build' your tank and
make it fit EXACTLY into its allotted space. Carve and sand the foam into
shape, rounding edges and corners. 'Organic' smooth shapes and curves tend
to do away with stress risers. That is A Good Thing. 80 grit sandpaper on
a small hand held sanding board cuts this stuff like butter.
After creating the tank in foam, THEN glass it using epoxy resin especially
formulated for tankage. Call the tech people at WEST, MAS, System Three,
or whatever other company you source your epoxy with. Since I do not know
the size of your completed tank, I cannot offer any suggestions as to a
layup schedule yet, but the tech support people can.
After epoxy glassing the tank, you can cut access holes and hatches. Cut
circular, not rectangular, access entries. I would glass in rim support
for the holes.
Then IN A WELL VENTILATED place, pour a pint of acetone into the
hole. (You can even use gasoline, but you never heard it here.) The foam
will disappear into a sludge that can be poured out leaving you with your
perfectly shaped tank shell.
This is an age-old process similar to 'lost wax' casting, except it is
'lost foam'.
Use the leftover epoxy and glass to make the inspection port covers. Get
something smooth. A piece of countertop cutoff from a cabinetmakers waste
bin, a piece of acrylic sheet, a piece of glass, you get the idea. Wax
that sucker like it was a 1932 Duesenberg. 12 coats are not too
many. Then lay out the epoxy-glass laminate directly on the waxed
surface. Cover with waxed paper and roll out with a solid roller (think
making biscuits here). This will give you a perfectly flat sheet of epoxy
glass composite ready to be shaped into covers for your access holes.
I use vacuum bagging techniques (Google is taking over the earth) for most
of my composite work, but doing it as outlined above will result in a great
tank. Custom made to take advantage of the space available.
You can also make fuel tanks this way. But I digress.
Tom
Tom & Jackie O'Meara
ex-Seaskate, Searunner 40 Tri
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
|