You're a belt and suspenders guy right after my own heart, Glenn, so
I'm curious. You're satisfied that welded HDPE will stay together,
long term, under the dynamic loading of water tanks? How big a tank
before you run out of confidence? And where does the air compressor
come in? Tell us more.....

Jim Woodward
www.mvFintry.com

Glenn Ashmore wrote in message news:E0Slb.90613$sp2.84885@lakeread04...
If you mean that melamine coated masonite, forget it. OK for short term
exposure in a shower surround but constantly soaked in a tank the water
will get through and turn the backing to mush. You may find some solid
plastic stuff a few racks down the aisle at the Home Despot that will
not absorb water. It is usually stuck to walls with Liquid nails or
other construction adhesive but I have not found an adheasive that will
stick to it reliably in a joint.

If you can build the tank outside and install it a laid up polyester or
epoxy FRP tank with a glued on lid would work. If you have access to an
air compressor and want to learn something new for a little less money
you can get a 4x8 sheet of 1/4" HDPE from a plastics distributor for
about $65 and a plastic welder from Harbor freight for another $25.
With a little practice on some scrap you can make a really nice tank
almost any shape you want. (Curves are not easy though)

Backyard Renegade wrote:

Hey folks, Scotty here.
What I am planning is some custom water tanks and such to be made to
fit inbetween two bulkheads. They will hold water for washing hands
and such, not necessarily drinking water. Any suggestions as to what
material and what adhesive/connectors to use to keep it watertight? I
was thinking some of that bathroom wall material they sell at Home
Depot, but would I use some kind of silicone, pvc cement, or would I
have to weld it, and if so, how?
Thanks for the input, Scotty

IF you do the weld RIGHT it will be about 80% as strong as the base
HDPE. The gun heats a stream of compressed air. About 8-12 psi and
blows it into the seam. It is really welding not gluing so you have to
make sure that the base material and the filler rod all melt together.

Thus far I have welded up a 7 gallon grey water holding tank to fit
inside the keel frame and a box to shield the back side of the
watermaker control panel. I pressure tested the grey water tank to 5
psi and it held together so I am pretty confident of it. OTOH, I do not
think I would try to weld up a 40 gallon tank or a any tank that I might
not want to smell if it sprung a leak. :-)

I was assuming that Scotty was looking for 10-15 gallon capacity tanks.
When you start talking about bouncing 2-300 pounds of liquid around
though I will leave that to a rotomolded tank.

It works for HD polyethylene used in water tanks and some other
thermoplastics but NOT for cross linked polyethylene used in fuel tanks
or UHMW poly.

Jim Woodward wrote:
You're a belt and suspenders guy right after my own heart, Glenn, so
I'm curious. You're satisfied that welded HDPE will stay together,
long term, under the dynamic loading of water tanks? How big a tank
before you run out of confidence? And where does the air compressor
come in? Tell us more.....

Jim Woodward
www.mvFintry.com

Glenn Ashmore wrote in message news:E0Slb.90613$sp2.84885@lakeread04...

If you mean that melamine coated masonite, forget it. OK for short term
exposure in a shower surround but constantly soaked in a tank the water
will get through and turn the backing to mush. You may find some solid
plastic stuff a few racks down the aisle at the Home Despot that will
not absorb water. It is usually stuck to walls with Liquid nails or
other construction adhesive but I have not found an adheasive that will
stick to it reliably in a joint.

If you can build the tank outside and install it a laid up polyester or
epoxy FRP tank with a glued on lid would work. If you have access to an
air compressor and want to learn something new for a little less money
you can get a 4x8 sheet of 1/4" HDPE from a plastics distributor for
about $65 and a plastic welder from Harbor freight for another $25.
With a little practice on some scrap you can make a really nice tank
almost any shape you want. (Curves are not easy though)

Backyard Renegade wrote:


Hey folks, Scotty here.
What I am planning is some custom water tanks and such to be made to
fit inbetween two bulkheads. They will hold water for washing hands
and such, not necessarily drinking water. Any suggestions as to what
material and what adhesive/connectors to use to keep it watertight? I
was thinking some of that bathroom wall material they sell at Home
Depot, but would I use some kind of silicone, pvc cement, or would I
have to weld it, and if so, how?
Thanks for the input, Scotty

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com