Making a 180 Gallon stand advice

[skrick]

hello everyone Im making my 180 gallon stand out of 3/4 maple plywood with 2 doors on either end and open in the middle all spacing between support dividers that run front to back are about 18" so there are 5 total supports of 24X33 high and all piece's of 3/4 inch plywood along the back. Personally I think it will be fine, but it is still alot of weight what do you guys think Im going to dress it up a bit here is my list of pieces.

2x tops and bottom 73x25
1x back pannel 72x33
supports x5 24x33
2 doors 18x32 3/4

all screwed and glued together I just want simple with some shelves all is #1 grade maple plywood
Sooooo........... do you guys think it will be fine I built my 90G stand like this and it turned out bulletproof some advice would be nice Thanks Bobby

[target]

For my stands I always like to have a 2x4 frame supporting the tank. The plywood becomes just the outside cover, not really for support. I just like the peace of mind it gives. You are about to put 2000 lbs worth of tank and water on top of 3/4" ply. For $10 worth of 2x4's, it's worth it in my opinion. Plus, making an internal frame would allow you bigger openings for access to under the stand. Just my 2 cents though.

[skrick]

I guess your right 2000lb vs a 90G is a big difference to build a frame 1st and then skin it better for protection I was just looking at my buddy's tank and its a 210G bowfront and its on pine from the store no big wood frame just looked shabby so Thats why I asked

[taureandragon76]

Ya most store bought stands don't have any framing inside but as Target said I would feel better having it framed then skinned

[skrick]

Done I will do the framed thing as I was a framer in my day too and woodworker so tools I have so I guess ill use them just being lazy also I just didnt want to add to the weight

[skrick]

Id like to add this is going on my 2nd floor also I looked at the joist situation looks to be ok rough cut 2x10 on a wall made of 2x6 framing on the exterior and the joist only span about 14' till the next wall tank is up against the wall

[Jonney_boy]

Either way will work as long as your floor holds

Building a 2x4 frame is easier and cheaper, in fact you can step down to 1/2" or 5/8" ply with no problems as the tank is supported.

Having said that, there are times I "want" to maxmize the space and will build the stand completely out of ply, if that is the case make sure you have enough supports (in your case 5 supports), double up the top, and the back is "inserted" into the cabinet. This will ensure the cabinet does not get out of square. .. no thin hardboard for a backing here, use the same 3/4" stuff .

You also want to ensure that the side pieces are inbetween the top and the bottom, helps allow for better weight transfer.

[gklaw]

Id like to add this is going on my 2nd floor also I looked at the joist situation looks to be ok rough cut 2x10 on a wall made of 2x6 framing on the exterior and the joist only span about 14' till the next wall tank is up against the wall

2x10 spanning 14' is a long way!

My 2x10 floor only spans 12.5ft - I think at 16" oc. It is bouncy. I have a 75g sitting one edge on a bearing wall. The floor does give.

I think you are probably fine with 1" plywood for the dividers - its the same price as Maple but stronger. Finish off with Maple doors and end gables ?

[skrick]

I know my floor does scares me but I just measured span is only 12.5ft to the next wall I could double up 2x10 my 110 is there now 48x18x31 and that sits up where this one would be along the exterior wall this one is spanned along a further distance of 6ft ill fill slowly and hope for the best I think ill do the plywood thing instead of 2x4 Ill build like my other stand with full sheet bracing along the front cant and cutout my doors cant go wrong aslo so it has the support like the back

[pistolpete]

If you're worried about a plywood only stand, consider this: the crush strength of birch plywood is around 300 lbs/square inch. That means that each linear inch of plywood can carry well over 200 lbs. So if you say that only the end walls of the stand are load bearing and your stand is 20 inches wide, then you have 4000lbs of load capacity in the end walls alone. Add to that front and back and perhaps a center support, and you end up with something like a 10x safety factor on a 180 gallon tank. With 3/4 inch material the slenderness ratio comes into play, but that is negated by the box shape of the
stand.

doubling up the top plate is absolute nonsense from a physics perspective, as it does nothing to improve load capacity, but making the back of the stand solid does help a lot. Stands framed with lumber are simply an easier way of doing things for people with limited woodworking skills.