DIY - Projects & Ideas • 300 gallon plywood tank build

[bernie comeau]

my plan for the brace is either a 3 inch wide piece of 1/2 inch acrylic or a 3/8 diameter aluminum rod

Yeah, that would work. Or fiberglassed wood could make a good brace as well. Even a silconed peice of glass will also do the trick.

Even if it does not show any deflection innitially, it will bend over time with out a brace. If it can bend 1/4" thick angle iron (1" sides on the insides) holding 3/4" fiberglassed plywood at only 24" deep, wood is definately going to bend in a 29" deep tank with out being braced horizontally

[rotccapt]

on your tank was the top just 3/4 inch ply with the angle iron attached to it? for my tank design i will have a 3.5 inch wood lip all the way around the top of the tank. attached to this is a 2.5 inch piece of wood as well so there will be a 90* frame all the way around the top of the tank

[lilscoots]

Your top frame should be very strong. If you're fiberglassing the rest of the wood, you'd probably be fine just ripping a 3-4" brace out the plywood you're using and fiberglass it. I'm not convinced you need a brace with the top framed like you're doing.

[bernie comeau]

I'm not convinced you need a brace with the top framed like you're doing.

So what tanks have you built and how many years have they held up well?. Size of tanks. Dimensions. type of build. how many years?

4 ft. you need a brace. 6 ft., even with angle iron 3ft. maybe you can get away with it. Wood is about the last thing you can get away with not using a brace, Better fiebergalss extremely well if you think you can get away with no bracing

[bernie comeau]

on your tank was the top just 3/4 inch ply with the angle iron attached to it? for my tank design i will have a 3.5 inch wood lip all the way around the top of the tank. attached to this is a 2.5 inch piece of wood as well so there will be a 90* frame all the way around the top of the tank

No, absolutely not. the tank has anagle iron all the way around . 2 1/4" around the whole front and 1 1/4'around the back and sides. The two top braces rusted through and were removed. They were on top of the tank and were exposed to the full evaporation of the tank. the rest of the angle iron is more then solid today as I grinded the surface rust away in 2009 and re-fiberglassed the whole tank inside and out including the angle iron. Wood will bend .....or you think i am talking for nothing

Helped my oldest brother build this tank in 1980, when i was almost 14. My dad welded the frame because he knew from previous tanks built, that water has a lot of pressure I built a few fiberglass tanks after this one, so I know what i am talking about!

[rotccapt]

im not denying that wood will bend. i am just trying to point out that a 3/4 inch ply tank with the angle iron for the top perimeter is build differently than mine will be. a 2x4 is a lot stronger than a piece of plywood. i am going to press on with my design and do my tests to see how much it bows and if i feel its too much then i will add a center brace

[bernie comeau]

a 2x4 is a lot stronger than a piece of plywood. i am going to press on with my design and do my tests to see how much it bows

2x4 can bend very easily, especially over some time under constant pressure. And no it is not stronger then angle iron, and certainly will bend a lot eaiser.

To me it's common sense to brace something that is 6 ft. long and under a lot of pressure 2 1/4" angle iron.....maybe you would not have to, but i still would. I-beam....you wouldn't have to
I've said enough, and i am done talking on this thread.

[rotccapt]

well i got a little bit more done on the stand. all the drawers are constructed and all i need to do is cut the bottoms for them. next up is coat the whole stand in kilz primer then i can start the electrical, ply top, and paneling

[JimA]

Curious why all the drawers and where is the sump and or equipment going? Nice build so far!

[13razorbackfan]

Curious why all the drawers and where is the sump and or equipment going? Nice build so far!

Was wondering the same thing...

[Mr.Dempsey]

If you guys notice the drawers are not very deep, he still has a lot of room to put a sump and equipment, how he plans on maintaining them as it will be hard to get to is another story.

[fusion]

"well got some more work done on the stand today. i have all the rails installed for the drawers and have all the material except the bottoms cut and routered so i am ready for more pocket holes and assembly. in the pics you will notice there is a large space behind the drawers this is for the sump which will run the whole length of the stand"

stated in an earlier post

nice work

[rotccapt]

like fusion posted the drawers only go half the stand width. also there are no horizontal bars between the drawers so to access the whole sump all i have to do is remove the drawers. also the side of the tank will have a door on it so i can access the end of the sump that will house the mecanical filtration. more to come.

also this stand is also a dresser that is what all the drawers are for

[rotccapt]

well the stand is done except the sheeting and the sump door. i ended up coating the whole stand in sanding sealer because i had it on hand. i did a water test on it and the water just beads up on the surface of the wood so i think it will work. i also got the wiring done so i have a 2 gang box mounted into the stand that is connected to a switch so when i do tank maintenance i just have to flip the switch and it kills the heaters and the pump. also i used a gfi plug on it so my tank will be gfi protected.

so after finishing the stand i started cutting the wood for the tank frame. all was well until i started dry fitting the parts and realized all of my boards for the tank sides were 3 inches too short. turns out when i was designing the tank my original plan was to butt joint the corners but after some though i decided a mitered corner would be better both in looks and strength. well when i made my cut list i made it before i changed my mind. so all is on hold till i go to the store and buy more wood. i will start drilling all my pocket holes though in the mean time.

[rotccapt]

well here are some pics of the progress. fist is a shot of my nics, green terror and a gourami that will be in the tank once built. also included is a shot of my sump compartment and wiring and a shot of the corners for the tank