my plywood tank build thread

[cubsfan]

I thought I would start a thread on my plywood tank build. It will measure 72*48*18 and will be an in wall design, which is why i went with plywood.
Bought 4 sheets of 3/4 inch plywood. Cut it to size, filled any imperfections with wood putty and then sanded, did this 3 times on each peace. Screwed the back and sides to the bottom piece (they actually sit on the bottom piece) using 2" triple coated deck screws, pre drilled all holes. Then painted the outside area with Kilz primer to help with any moisture that will be in the air. I will be ordering the fiberglass next week, this will be the hard part! Not the ordering but the actual fiberglassing

The glass will be 3/8 inch thick, at about $52 dollars with complete polish (no sharp edges). Here are some pictures so far.

Will take any advice out there

 

[tankyou]

Good luck, I'll be observing with interest.

BTW, where/how are you planning on putting your bulkhead fittings? Do you plan to glass them over?

 

[toddc]

I'll be watching this thread with interest as well..... I am a composites/fiberglass fabricator by trade and have seriously considered doing the same thing myself.
Are you using a polyester or epoxy based resin system for your tank?

 

[cannonman]

This will be fun to watch! Don't leave us hang'n, you have to post and update regularly!!

 

[rudezuk]

We are talking about doing this right now. Building a tank to our specs, but possibly a corner unit.
I have thought about lining the inside of the tank with 1/8" acrylic too.
Any thoughts?

 

[cubsfan]

I will be looking at using fiberglass cloth, around 7 oz, and using epoxy.
as for the bulkheads, i plan on drilling them the same as you would for a regular aquarium. I will have 2 1" bulkheads on the bottom back corners and probably 2 closed loop systems, 1 on each side to help with flow.
as far as lining the inside with 1/8" acrylic, are you talking like a pond liner? I have read if using a pond liner the fish can pick at it or your live rock can fall and cause damage to it.
I will try to keep everyone updated as I go.
thanks for reading

 

[tankyou]

You know, now that I look at it a little closer, I don't think those screws alone will be up to the task of holding your corners together. Afraid that once loaded they will rip through plywood. :scared:
While your glass cloth will take a lot of that strain, I'd reinforce all your joints with some straps or braces if I were you none the less.

 

[cubsfan]

there will be a full brace system around the entire tank with 2x4's. also there will be a brace over the top of the tank to help with deflection.

 

[psusocr1]

IMO i would be using one no less than 3/4" and i would personally use 1" marine exterior grade plywood and no less for this project. At about 60-80 bucks a sheet depending where you livew its not cheap, but DEFINANTLY worth it in the long run...
its said that less 2x4" and 4x4's for support and a thicker wood will be better for the structure and bending of the tank..
also check out west systems epoxy and cloth.. its great stuff
also i would DEF. go no less than 3/4" inch safety glass or thats a big problem...

 

[trainfever]

As a model railroader, I can give you a few ideas. before you lay the fiberglass sheets,line the inside of the "box" with 2" foam sheets, the pink stuff. You cab build it up with a few layers. You can carve it into caves or overhangs and what not. Then cover everything with the fiberglass. While the epoxy is still drying, spread a light coating of sand over top of it. The sand will stick to the epoxy and will give the sides a natural look. You can give the sides a really neat effect by doing this.

 

[phixer]

This should be a neat thread to follow. I have a lot to throw at you, take it or leave it either way hope it helps.
1. I would recommend framing it also by building a vertical exoskeleton around it, epoxy is brittle when dry any flex will cause it to check (hairline cracks). Fiberglass helps to strengthen it but over the years the epoxy will still become brittle from UV exposure (oriented for marine use) and check. If the tank is moved or filled the temp of the water can cause the epoxy to check. Top grade marine plywood will cost even more. Okoume runs about 140 bucks a sheet, 60 - 80 bucks for 3/4 marine ply (even Fir) is cheap. This sounds funny but concrete board (Hardiboard) works very well also and is significantly less expensive.
2. Dont line with acrylic or PVC sheet. Acrylic is a great material but in the thinner thicknesses acrylic will crack along the seams if it flexes even a tiny bit. Thin PVC sheeting will become brittle and crack along the edges also.
As mentioned Plywood/Fiberglass/epoxy paint works well but is also brittle after a few years. You might want to look at Sanitred. I was very skeptical at first but this product has some merit for aquarium building applications. Many use it directly over the plywood or fiberglass because it is tough and remains flexible, it can also be applied at any thickness.
How will you be mounting the viewing window?
One of the weakpoints in these type of tanks to consider and beef up is the seal around the window. The water pressure pushing outward will form a good seal against the face but the area to the side is where the silicone can be forced out. Kind of like a blown head gasket. The lateral pressure pushes the seal out. I recommed insetting the window. (Wish I could upload a picture).
Id to upload some drawings in paint but this site wont accept them for some reason.
Trying to keep this short, but you may also want to look at Sanitred as mentioned. This material looks to be one of the best flexible sealants around for DIY plywood tanks.
Have seen many tanks made this way that last for years.
This will give you some good information.
Google this: 1122.08 GALLON TANK PROJECT!!!

 

[aw2x3]

Originally Posted by Phixer
This will give you some good information.
Google this: 1122.08 GALLON TANK PROJECT!!!
Thank you for posting that, Phixer. That guy says he sealed his with 1/8 sheets of acrylic, instead of fiberglass. A year ago, I wanted to build a large plywood tank, and seal it with acrylic. Many, many people, over at --, told me it couldnt be done, so I gave up on the idea.
Maybe my plywood tank idea will start getting reworked now.

 

[aw2x3]

Originally Posted by Phixer
This will give you some good information.
Google this: 1122.08 GALLON TANK PROJECT!!!
Thank you for posting that, Phixer. That guy says he sealed his with 1/8 sheets of acrylic, instead of fiberglass. A year ago, I wanted to build a large plywood tank, and seal it with acrylic. Many, many people, over at --, told me it couldnt be done, so I gave up on the idea.
Maybe my plywood tank idea will start getting reworked now. I was thinking of something in the 500gal. range.

 

[cubsfan]

i will look into the sani-tred more. thanks

 

[phixer]

AW have you checked out Joe Salvatoris 1700 gallon shark tank?, its plywood construction. Its an older thread but I think you will like it. Plywood tanks are great. If the tank sits next to a wall most of the viewing is from one side anyhow, why not use plywood and build it bigger and for less $$$ I say.

 

[aw2x3]

I've been wanting a 2 sided plywood tank for a long time...front viewing and one panel side viewing.
I was all over it, trying to come up with different methods, but people on -- shot them down, one after the other. I want to try to find a way to do it without having to use the epoxy and fiberglass, etc.
I can get 1" glass CHEAP...it's always been the build that's given me trouble. Now, looks like I need to go back to planning.
I'm thinking 84L x 60W x 30H.

 

[phixer]

If you dont want to use the epoxy/fiberglass method check out Sanitred. Ive even seen drylock work.

 

[cubsfan]

Originally Posted by Phixer
If you dont want to use the epoxy/fiberglass method check out Sanitred. Ive even seen drylock work.
Well I got through 61 pages of that thread, out of 112

!!
His drylock has worked from as far as i read. Yet another option to think about.

 

[phixer]

He eventually had a leak but not from the drylock. I think he said it was plumbing related. Its in the thread somewhere.

 

[cubsfan]

yes it was a plumbing leak from one of his spray bars. So far only 100 pages in, 12 more to go. But now I'm seriously looking at doing it with drylock. Less odor than with the fiber/epoxy and it seams easier. Still looking at the sani-tred also.