Here's a sketch of my idea for a tank stand for my 180gallon. The idea is to leave room for another tank, maybe a 40 breeder or 55, below and the back open for storage and cords, hoses etc.
The uprights are 4x4s, the horizontal pieces at the top are 2x6 and the ones on bottom are 2x4s. The sides will be covered in plywood and there will be knee braces at all four corners on the back to prevent racking. The bottom shelf and the top will be covered with 3/4" plywood. There will also be additional 2x4s from the 2x4s at bottom to the 2x6s at top on both outsides of each 4x4 post to support the upper 2x6s and to have something to attach trim to. The 2x6 frame around the top outside will be lag bolted through the 4x4s.
The dimensions at the outside corners of the 4x4 posts are 6' long and 2' wide. The 2x6 bracing is outside the actual footprint of the tank.
My concern is whether or not I can really get away without having a center brace. Anyone care to comment?
Thanks for the input. It's much appreciated. In my head I knew it was sufficient, but my heart wanted me to get secondary opinions. In fact a mechanical engineer friend of mine is looking at it too. But he doesn't have any experience with aquarium stands.
You mention doing away with the 4x4s. In favor of what? Two 2x4s turned at right angles to each other? That would make the lag bolts shorter. Hmmm....
I'd do the 2 2x4x "L" fashion. I'd also drop a bead of Glue on it to make the joint stronger. also make sure that the direction of your 2x4 verticals opposes your end joint of the top of the stand. If that makes sense.
Make it so one of your 2x4's is supporting both the short side of the top and the long horizontal section... **** this is hard to explain... Hang on
Hey, thanks! I actually knew what you meant but visual aids are always good. I'll make this change because I think it just makes sense. I also plan on gluing as many of the joints as I reasonably can, it can't hurt. When I built my 20 gallon tank I wasn't too worried about the weight, but I glued all the structurally important joints as well as putting a dab of glue on every pre-drilled hole before running the screws in.
A tank in itself is rigid in the vertical dimension. The glass does bow out slightly on the horizontal, but in the vertical you would have to deflect 18 to 20 inches of glass. I hope that makes sense. Really a glass tank acts like a beam and you don't have to worry about center supports.
In the interests of saving weight I'd recommend eliminating 4 out of the five cross braces in the top, they add nothing. Unless this is an Acrylic tank, in which case leave them in. Also give some thought to wood shrinkage. A 2x6 from the lumber yard will shrink about 1/8" in width after a couple of months in a heated room, but not at all in length. So you want to start with dry straight sticks. I always dry my dimensional lumber for a few months, or build 100% plywood stands.
Things may be a bit different in different places but here, it might be more difficult to get the 4X4 in a good dry stick. I would go with the 2-2X4's as shown. They will be far less likely to twist as they work against each other. The single 4X4 has all the same grain and can do more as it chooses. The 2X will also most likely be cheaper and lighter for the same amount of strength. I would cut the top back to 2X as well and maybe two or three cross braces. I go with glue and screws on the joints.
Thanks guys. Excellent points about the 4x4. I'm used to working with steel rather than wood so it was stuff I hadn't really considered. The only place I'm really set on using 2x6 is around the outside, especially the front and back. I think the rest could comfortably be 2x4s. I know 2x4s would probably suffice, but it's a little extra insurance that will make me feel better. I'll also cut it down to 3 cross braces across the top to match the bottom.
Thanks again. I plan to build this Saturday so I'll post some pics.