considering a plywood tank build, help please!

[Vance]

I'm toying around with the idea of building a plywood tank with 2 viewing sides, instead of buying a full glass tank for my next upgrade and was wondering what you guys think?

The space I have to fill is 84"x50" including bracing and all other structural elements. I would really like the front panel of glass to be around 30"-32" high and as long as I can get in this space, i assume around 70"? Would this be possible with starfire glass? Garfs online calculators have a recommendation not to go over 24" high with this sort of length.

Any help is appreciated!!!

 

[nitro]

Hello
Go to YouTube and search diy plywood tank and there is a complete series on that exact topic. I think it is by a guy called mr. Diy good watch.
Nitro

 

[Vance]

So 3/4" for leaded should be okay? Step up to 1" for starfire as long as i don't have water deeper than 30"? I do plan on having center bracing.

 

[radiata]

Random thoughts...

A while back (30 years?) there was a marine grade plywood that was the preferred plywood for tanks. I recollect the manufacturer used epoxy to glue the plys together.

The interior of most wooden tanks are coated with epoxy paint. I think you'll find that urchins can chew through the epoxy layer.

I believe that Formica has been used to line wooden tanks. Comes in a variety of colors. It reduces the chances of leaks, where only the tank corners become possible origins for a leak. Of course it could crack if a tank bowed excessively - but so could epoxy.

Lastly, I don't think plywood tanks have much of a life expectancy. I have two O'Dell glass tanks, a 65 and a 95, that are each 35 years old and still in service. You'll never get that longevity from plywood tanks.

If you live anywhere near a public/commercial aquarium, you might want to attempt to pick their brains. I've been on behind-the-scenes tours of the Brooklyn Aquarium (where I saw wooden tanks) and I've talked my way behind-the-scenes at another.

Good luck...

 

[Vance]

Thank you for the tips radiata! I work in the boating industry so marine grade plywood shouldn't be to hard to find.

I was planning on fiberglass cloth and resin to reinforce and seal with some sort of seal coat on top of that. Don't think a gel coat would have the durability though... d@*m! That would sure make it easy if it did! Sure an urchin could still wear any of those down. And was already planning on sanding a resealing after about 10 years of use.

Still a little apprehensive about glass panel though. Some calculators tell me 3/4 inch has a safety rating of 3.8 and others (like garf) wont do the calculations for that water depth. Tank will have 4" euro bracing on top spaced ~ 2' apart. Does anyone have any experience with glass?

 

[Vance]

I guess my question is; do I need two panels of glass in the front? Or can I get away with one? Length roughly 76" water height 30"

 

[Maximizer]

Are you absolutely sold on a plywood tank and 2 viewing windows? If not you can try one of these tanks(link is below). I plan on buying one this summer for my next build, free shipping and only $70 crating charge. Not too bad of a price either. And there's a 10% off promo code on their website. You could spruce up the outside with wood to make it look real nice.
http://pentairaes.com/fiberglass-tanks-with-window.html

 

[Epicreefster]

I have built a plywood tank in the past and currently build large glass tanks. You will be fine with 3/4" glass in those dimensions, doesn't matter if it's green glass or starphire. After having built both types of tanks I would build in all glass. It can be a real PITA to seal the window into the tank, and it's not that much more. You would be looking at $1200-1500 for the plywood tank and $2000 for the glass in materials.

 

[rayn]

I had planned and sourced star fire glass at the 30" height. Tank was 8' long and was only 3/4" thick. You should be fine there

I planned a epoxy paint over a fiberglass layer. If I can find pics I will post them. But I biscut joined all edges and used a 4*4 cut at a 45 angle for corners. Use small bumpers, like for cabinet doors to space out the glass and lower onto those after applying caulk.

 

[Vance]

Awesome, that eases my mind quite a bit. I'm much more confident in my wood skills than glass skills.

Ryan, what epoxy did you use? Thats an awesome idea for the corners! Thank you, I hate the square framing look all around the seams inside the tank.