Hi all,

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
anyone had some advice about how to seal the seams of the tank - like
where the walls meet the floor. I was thinking of taking some 2" wide
fiberglass tape and putting that on the seams, but I wasn't sure if
this was a good idea or not.

I was also planning on putting 2 or 3 penetrating layers of epoxy and
then 2 coats of fiberglass/epoxy on top of that.

It's pretty much the exact opposite of a boat - I want to keep the
water inside

I'd appreciate any help you can offer.
-William

wrote:

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
anyone had some advice about how to seal the seams of the tank - like
where the walls meet the floor. I was thinking of taking some 2" wide
fiberglass tape and putting that on the seams, but I wasn't sure if
this was a good idea or not.

I have built several tanks using this approach using plywood, double
bias glass and epoxy.

Cut strips of glass about 4" wide for the seams.

If you are creative and have some clamps, it is possible to assemble the
tank without using any fasteners at all.

Just clamp some 2"x2"x6" pieces temporarily in the corners and lay some
4" glass strips to tack everything together.

Cut the flat interior pieces of glass about 1"-2" undersize. Use the 4"
wide strips of the seams to overlay.

I'd use about 3-4 layers of 17 OZ (DB170) on BOTH the inside and outside.

This will totally encapsulate the plywood.

When you are finished, coat the inside of the tank with "tank resin"
(Not the same as laminating resin)

You will be long gone and that tank will still be in service.

Lew

On Feb 20, 3:19 pm, Lew Hodgett wrote:
wrote:

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
anyone had some advice about how to seal the seams of the tank - like
where the walls meet the floor. I was thinking of taking some 2" wide
fiberglass tape and putting that on the seams, but I wasn't sure if
this was a good idea or not.

I have built several tanks using this approach using plywood, double
bias glass and epoxy.

Cut strips of glass about 4" wide for the seams.

If you are creative and have some clamps, it is possible to assemble the
tank without using any fasteners at all.

Just clamp some 2"x2"x6" pieces temporarily in the corners and lay some
4" glass strips to tack everything together.

Cut the flat interior pieces of glass about 1"-2" undersize. Use the 4"
wide strips of the seams to overlay.

I'd use about 3-4 layers of 17 OZ (DB170) on BOTH the inside and outside.

This will totally encapsulate the plywood.

When you are finished, coat the inside of the tank with "tank resin"
(Not the same as laminating resin)

You will be long gone and that tank will still be in service.

Lew

That sounds good Lew. I was planning on using the basic no-blush epoxy
from this company - http://www.epoxyproducts.com/1_marineresins.html

I assume this pretty similar to the "tank resin" that you're talking
about.

-William

On Feb 20, 3:19 pm, Lew Hodgett wrote:
wrote:

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
anyone had some advice about how to seal the seams of the tank - like
where the walls meet the floor. I was thinking of taking some 2" wide
fiberglass tape and putting that on the seams, but I wasn't sure if
this was a good idea or not.

I have built several tanks using this approach using plywood, double
bias glass and epoxy.

Cut strips of glass about 4" wide for the seams.

If you are creative and have some clamps, it is possible to assemble the
tank without using any fasteners at all.

Just clamp some 2"x2"x6" pieces temporarily in the corners and lay some
4" glass strips to tack everything together.

Cut the flat interior pieces of glass about 1"-2" undersize. Use the 4"
wide strips of the seams to overlay.

I'd use about 3-4 layers of 17 OZ (DB170) on BOTH the inside and outside.

This will totally encapsulate the plywood.

When you are finished, coat the inside of the tank with "tank resin"
(Not the same as laminating resin)

You will be long gone and that tank will still be in service.

Lew

That sounds good Lew. I was planning on using the basic no-blush epoxy
from this company - http://www.epoxyproducts.com/1_marineresins.html

I assume this pretty similar to the "tank resin" that you're talking
about.

-William

wrote:


That sounds good Lew. I was planning on using the basic no-blush epoxy
from this company - http://www.epoxyproducts.com/1_marineresins.html

I assume this pretty similar to the "tank resin" that you're talking
about.


Don't have a clue about the above; however, there is a BIG difference
between laminating resin and tank resin.

Laminating resin contains NO VOC's and tank resin which is approved by
USGov't for tank interiors, does contain VOC's.

BTW, just looked at the size of your tank again.

I'd use 4x8x1/2 CDX plywood for core material.

Get a bag of micro-balloons to make putty to fill exterior voids in
plywood.

If you don't have one, buy a 4" right angle sander and lots of 24 grit
disks. You are going to need them.

You are going to need a staging area where you can build those 4x4x12
plywood panels.

Assume you realize that in addition to at least a month of your time,
expect to spend about $1,000.00 for materials.

Depending on where you live, might be able to suggest some suppliers,
if that would help.

Lew

I have gone thru a 6 Gal set I got in San Diego. Really happy with
this guy, has everything.
http://www.jgreer.com/ (877)342-8860
or on ebay,
http://stores.ebay.com/AeroMarine-Products
As Lou says depends on where you are.

Den 48ft YF

I assume by 'tank resins' Lew means epoxy paints which are only
slightly different from marine epoxy resins in that they have pigments,
some thixo additives and often are less brittle.

paul oman
progressive epoxy polymers
www.epoxyproducts.com

wrote:
Hi all,

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
anyone had some advice about how to seal the seams of the tank -
like where the walls meet the floor. I was thinking of taking some
2" wide fiberglass tape and putting that on the seams, but I wasn't
sure if this was a good idea or not.

I was also planning on putting 2 or 3 penetrating layers of epoxy
and then 2 coats of fiberglass/epoxy on top of that.

It's pretty much the exact opposite of a boat - I want to keep the
water inside

I'd appreciate any help you can offer.
-William

I used a 3/4" plywood tank for water on my sailboat for 20 years,
lived aboard for 10 years. The only thing inside was 2-3 coats of
Gluvit, never any leaks or problems.
http://www.marinetex.com/PRODUCT%20P...it/gluvit%20pr
od%20in.htm


--

dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

On Tue, 27 Feb 2007 15:32:58 GMT, "dadiOH"
wrote:

wrote:
Hi all,

I'm building a large water tank (4' x 4' x 12') out of plywood and
fiberglass (wood outside, fiberglass inside). I was wondering if
SNIP SNIP

I think it might be a good idea to seal the outside of your tank as
well. I would use a lightweight glass and either epoxy or poly resin.
It will stop moisture penetration which will help reduce any movement
which might cause your seams to fail.

Joe