Hello all, first post here. My first plywood tank build

Hello all! New to the site. I was hoping I could get some advice on this tank build I am planning. I tried to catch as many different angles and phases of the drawings as I thought would be the most helpful. Anyhow this is about 460 gallons if my calculations are correct. All the viewing panels are a little more than 32 inches tall. The center main viewing panel is about 58 inches wide, and the two side viewing panels are just under 11 inches wide. The inside will be lined with 3/4” plywood, then fiber glassed at the seams, if not the entire interior, then pond armor on top of that. I was going to go with ½” thick glass for the viewing panels. All lumber is 2x4’s except the 10 or so floor supports which are 4x4’s. My question is does this seem structurally sound enough to anyone with experience building these types of tanks. Especially considering the lack of cross bracing on the top. If it’s recommended to add I will, but I’d prefer to go without if it won’t be a problem. Would 1/2” thick glass be enough? Could I get away with something smaller? Any other observations or recommendations are greatly appreciated.

 

Wow! Good luck! Maybe you can google similar constructions?

 

Welcome to Fishlore!

Is this a stand or tank made of wood?

 

Cool idea for a tank, I can't wait to see it finished. How will the glass interface with the frame? Do you have drawings of that?

 

Welcome to Fishlore!

Is this a stand or tank made of wood?

Its one piece stand and tank. The frame is all lumber assembled as shown.

Cool idea for a tank, I can't wait to see it finished. How will the glass interface with the frame? Do you have drawings of that?

The inside will be lined with plywood, then fiberglass the seams, then paint the entire interior with pond armor. Once that is done I will use silicone to seal the glass to the pond armor epoxy surface.

 

Welcome to fishlore.
Seems pretty sturdy to me but i know nothing about plywood builds other then i would love one. I cant wait to see how it turns out. What are you planning on stocking it with?

 

What program did you use to make those plans?

 

What program did you use to make those plans?

SketchUp
After gathering some feedback on this and other forums I’ve modified my plans a bit.

I changed the floor to use 2x6’s instead of 2x4’s for the added strength. I also changed the top perimeter bracing to be 2x6s as well.

However, I’ve run into another issue. The ¾” glass viewing panels of this size are much more expensive than I thought they were going to be. As an alternative I am considering using ¾” acrylic. Does anyone have any experience using acrylic as viewing panels in a plywood tank? I’ve read that there may be issues getting it to seal, like the silicone does not adhere to the acrylic as well as it would to glass. Just curious if anyone else has run into this concern and what some possible solutions may be.

 

SketchUp
After gathering some feedback on this and other forums I’ve modified my plans a bit.

I changed the floor to use 2x6’s instead of 2x4’s for the added strength. I also changed the top perimeter bracing to be 2x6s as well.

However, I’ve run into another issue. The ¾” glass viewing panels of this size are much more expensive than I thought they were going to be. As an alternative I am considering using ¾” acrylic. Does anyone have any experience using acrylic as viewing panels in a plywood tank? I’ve read that there may be issues getting it to seal, like the silicone does not adhere to the acrylic as well as it would to glass. Just curious if anyone else has run into this concern and what some possible solutions may be.

I would advise against acrylic for two reasons.

1. It can flex and bow which could ruin your seal and create a leak.

2. It scratches super easy, and with the viewing panel at about floor level as it looks like in your drawing, it would get ruined pretty fast.

Also keep in mind when looking for the glass, you want low iron glass, otherwise it will look very green.

Finally, how are you determining what size glass you do need? There must be a calculator somewhere to determine what size glass you truly need. In my reading, it seemed like acrylic was also more expensive then glass, have you priced it yet? It seems people use acrylic to save weight, not money

 

I would advise against acrylic for two reasons.

1. It can flex and bow which could ruin your seal and create a leak.

2. It scratches super easy, and with the viewing panel at about floor level as it looks like in your drawing, it would get ruined pretty fast.

Also keep in mind when looking for the glass, you want low iron glass, otherwise it will look very green.

Finally, how are you determining what size glass you do need? There must be a calculator somewhere to determine what size glass you truly need. In my reading, it seemed like acrylic was also more expensive then glass, have you priced it yet? It seems people use acrylic to save weight, not money

Y
I found one source online that tried and appears to be successful in using acrylic in a plywood tanks.

I used this calculator, but verified with the vendor as well. Well the excel sheet wont attach, but I'll attach a snapshot of both a formula I found as well as a calculator provided by a plastic supplier that I can't seem to find now. Come to think of it, I think I found these in the forum that you mentioned. Regarding costs, I called alot of places and on average glass for the same size acrylic was 3 times the costs

 

pics of the progress