ever built a plywood tank?

[Kent E.]

I'm considering building a plywood tank and want to get some input from anyone who has. Was it worth the effort? Did you use fiberglass? Did it last?

[wanareef]

I've built several out of ply. Use 3/4" CDX - exterior glue, screws, waterproff glue. Basically it's a "box" with a frame in the front and the glass goes in the frame. You would use silicone - aquarium safe silicone.

On the inside corners, I use a 4" wide woven glass cloth epoxyed in. Then I poured onto each "side" up to a 1/8" thick layer of epoxy, let dry and did the same for all sides. this acts as the liner. Also since epoxy is clear, you can add or mix color in as you are mixing the 2 parts together.

Across the top, just 2 - 3 bars for a brace. Stainless steel threaded rod with a washer and nut on the ends - this was for an inwall tank so you didn't care. If no then dadoe for the washers and you'll just have a little part of the nut showing. The hood can cover this up. The rods are for strenght across the top and to allow light thru. I just used 3/8" glass for the front. It was only 24" tall.

If you drill the tank, just make up some more of the epoxy to coat the hole - let dry and then install your BH's.

[jesspaul]

Did you use the water tank epoxy or the standard auto marine type epoxy?

[Doug1]

Back in the 70s i helped build several of these as outlined above, used regular fiberglas cloth and resin. Now adays they have better epoxy, either should be fine if cured properly tho the water tank epoxy should be rated for potable water systems.
Given the cost of materiels nowadays I am not sure that it's that much cheaper any more

[Kent E.]

Good info,
Is GE #1 silicone considered aquarium appropriate or should I go to a glass shop? Pressure seals, not tension.

[Kent E.]

Doug,
How long did those tanks last?

[wanareef]

Ge #1 does not have the mold inhibitor and can get it at HD

Doug - your right. After several gals of epoxy - that's about $150 + cost of material, you could make an acrylic one for almost that price (that is if you are handy with acrylic) but then the cost of acrylic keeps going up every month, I know cause I buy the stuff in sheets and tubes. 10" 1/8" wall cast tube cost me $55/ft @ 6' length. I will be building my own tank and using 1/2" cast , three months ago it was $150 a sheet, now it's $185 and still going up.

My friend still has my old ply tank, I built it 15 yrs ago and it's still holding water. I had it for 9yrs. A little beat up on the outside, but still holding water.

[Kent E.]

Wow! now that is cool and encouraging. Last thing I want is gals and gals on my living room floor! Wanabe, I know its at HD and it doesn't have mold inhibitors, but is it aquarium appropriate? I'm using in my tank now but its just in some non-critical points not holding the glass together.

[wanareef]

On those non critical areas, are the joints clean and does the glass meet? Parallel to one another?

[Kent E.]

It is sealing my diy bulkheads and overflow box that I made, not connecting glass.

[Geoff]

here is an earlier thread on building a plywood tank.

G~

[Kent E.]

Great thread! very helpful. I hope to do slightly different framing. No corner supports for the frone and side glass.