Question for Plywood Tank-ers

[kestrel]

I've thought about the idea of building a large plywood tank in the basement, sometime in the future. One concern that I have is re-painting the inside. I'm assuming the finish needs to be redone after some time. How long will it last?

Also along a similar line - Has anyone ever considered building a plywood tank and lining the inside with a sheet of thin acrylic, say 1/8"? I would still use a glass plate for the front viewing panel. It would be much cheaper than an acrylic or glass tank, and I think it would be more durable than the painted plywood.

Anyone have any thoughts?

Thanks
Daryl

[Geoff]

this is just brainstorming here, but i do not think doing the tank within a tank thing would work. unless you are able to make it fit exactly inside the box, and the outside box would not flex at all. i think anykind of stress would pop the seams on 1/8" acrylic. unless you are a perfect carpenter i feel the seams would eventually give out.

.02

G~

[David Grigor]

The research I did before building is that the epoxy paint will outlast the silicone of most glass tanks.

Plywood tank should last 10s of years.........

Durability should not be an issue.

[oregon_gorge]

I have been doing some research after reading Davids post on building this exact thing. I am going to build a 6' long, 36'' deep and 30'' tall plywood tank with a 1/2'' thick glass front to replace our 240g acrylic tank.

I went to the paint pros and they said to use a 2 part epoxy that is made for painting the inside of water tanks like the city uses. BIG ones! He said that it will hold up to UV and salt just fine. Look at the post in ''Lets see your 300's'', or something similar, here on TRT. It gives you and idea to start from. It got me!

Good luck, Chris

[Casie]

Great read on a 500 plywood build here!

[David Grigor]

One other thing to keep in mind is humidity factors of a big tank. Mine is located in the basement. I put it up in the middle of summer. Humidity in the WHOLE house was 60-65% If I did nothing. To keep it down I was using the biggest humidifier the whirlpool makes and pratically run all day ( 600W ) and would only lower it to 55% which is still the upper limit for electronic equipment.

Of course, there are lots of factors such as your climate, how you how is insulated, ventilation etc. but my total water volumne is about 400g and even if I wanted to I can't go bigger without major changes to the house. I imagine you would need to totally seal off the tank room from the rest of the house and use seperate ventilation for the tank room. Adding exhaust fans to my existing house really isn't an option for me because not unusual summer and winter for the outside humidity to be even higher than inside so drawing in the outside air wouldn't help.........

Becuase of heating currently humidity is in the 40s ( still causes fog on the windows ). When summer time hits, I know it will have to do something else. First thing will be glass tops and see if that helps any.

[aquaticsdeptleader]

how do you compensate for the expansion and contraction of the plywood, wont it split one of the epoxy seems?

jim

[David Grigor]

I am not aware and have not read of any contraction/expansion issues at the seams.........

Putting a level on the back my plywood bows about a 1/4" but it flat near on top/bottom/sides because of the screws.

Can't speak for others but my screws are only 1.5" apart which is probably way overkill as the general plans I was using from Simplified Reefkeeping book called for every 6"........

[SPC]

Posted by aquaticsdeptleader:
how do you compensate for the expansion and contraction of the plywood, wont it split one of the epoxy seems?

-You should not see any problem with this using plywood. The advantage of plywood is it does not expand and contract to any noticeable degree unless it gets wet.
Steve