Stand design to maximize sump space?

[TimeTwister]

So I am building a new stand for my 75g as part of a reboot after moving. My old stand was made assuming I would upgrade to a 6' tank so I had a good amount of space under the tank and made a DIY sump out of a 55. This time around I want to build the stand so it fits the tank more exactly, but still want to maximize under cabinet space.

I took the typical 2x4 frame design most people use but modified it so instead of two 2x4's at every corner for vertical support I would use 1 2x6. I would also skin the sides with plywood to help reducing the chance of front to back racking of the frame.

This design should allow me to fit my old 55 sump in the stand (just barely). Does it seem structurally sound, or am I better off sticking with the mode traditional design and build/buy a smaller sump?

Also I know I am missing the cross braces in the top and bottom frame, this was just a quick illustration to show the vertical supports.

 

[TheEngineer]

You need vertical supports that go all the way to the ground. Otherwise you’re relying on the screws to hold the entire weight of the tank.

 

[TimeTwister]

You need vertical supports that go all the way to the ground. Otherwise you’re relying on the screws to hold the entire weight of the tank.

Nothing in my design is supported by just screws. If you look at the design both the short part of the frame (sides) and the long parts of the frame (front and back) sit on the 2x6 vertical supports.

 

[Antics]

Nothing in my design is supported by just screws. If you look at the design both the short part of the frame (sides) and the long parts of the frame (front and back) sit on the 2x6 vertical supports.

I think @TheEngineer means the normal vertical supports that you screw the green 2x4's into are needed to prevent them (or help prevent) racking. Your design is basically relying on either pocket screws for the green boards or screws coming through the blue plywood. If you use enough plywood your design will probably be fine, but I'm not comfortable enough to give specific opinion on the issue.

 

[TheEngineer]

Nothing in my design is supported by just screws. If you look at the design both the short part of the frame (sides) and the long parts of the frame (front and back) sit on the 2x6 vertical supports.

I’m talking about how you are transferring the load to the floor. Right now whatever you are using to attach the vertical supports to the 2x6 on the floor is all that holds the stand in place. Screws have very poor shear strength. There should be another vertical leg that goes all the way to the floor on all 4 corners

 

[TimeTwister]

I think @TheEngineer means the normal vertical supports that you screw the green 2x4's into are needed to prevent them (or help prevent) racking. Your design is basically relying on either pocket screws for the green boards or screws coming through the blue plywood. If you use enough plywood your design will probably be fine, but I'm not comfortable enough to give specific opinion on the issue.

Ah that makes more sense. I thought he was referring to the other common design mistake where the frame is screwed to the side of the vertical supports, relying on the sheer strength of the screw for support vs it sitting directly on the wood support.

The plan was to use pocket screws to connect the green vertical supports to the frame and the plywood skin for added racking support just as you said. I thought about doing some kind of rabbit or possible a mortise joint to address both the stability concerns, but my table saw accuracy is pretty bad, and if I had a good enough one to mess with fancy joints I would just do a cabinet style build our of just 3/4'' baltic birch plywood (which is what i really prefer to do). The 2x4 design is just more forgiving to tool, and if i am honest with myself, skill capabilities.

 

[Erica-Renee]

Just build a plywood shell.. No need for 2x lumber But your design is Sound

 

[Fishinbob]

Your design is absolutely fine... if not overkill lol. I've built atleast a dozen custom stands with and without the 2x4 base frame with no center brace. The original rocket engineer design was way beyond sufficient especially with a plywood skin. You've thought it through at most add a half back for additional racking support.

 

[TimeTwister]

Thanks for the feedback all. I figured the design was still overkill. My last stand was the typical 2x4 design but built at dimensions to support a 180, plus skinned in 3/4 ply wood on the sides, front, top and inside shelf. I never questioned it's support or stability but it weighed a ton and was beyond overkill.

This time I want something much less overkill, but also don't want to cringe in fear every time it gets bumped into.

 

[davocean]

Personally I've always laid those bottom orange 2x's flat instead of on edge, just seems more stable, and I screw up into the verticals.

I get what was meant, a leg to floor of some kind keeps from racking or relying on pocket screws, especially w/ that 2x on edge as is, but ply on face would also work for shear strength resolving that.

 

[N2theUnknown]

So I am building a new stand for my 75g as part of a reboot after moving. My old stand was made assuming I would upgrade to a 6' tank so I had a good amount of space under the tank and made a DIY sump out of a 55. This time around I want to build the stand so it fits the tank more exactly, but still want to maximize under cabinet space.

I took the typical 2x4 frame design most people use but modified it so instead of two 2x4's at every corner for vertical support I would use 1 2x6. I would also skin the sides with plywood to help reducing the chance of front to back racking of the frame.

This design should allow me to fit my old 55 sump in the stand (just barely). Does it seem structurally sound, or am I better off sticking with the mode traditional design and build/buy a smaller sump?

Also I know I am missing the cross braces in the top and bottom frame, this was just a quick illustration to show the vertical supports.

Dont want to get off topic but what did you use to make your design? (What app or program)

 

[Cjud7982]

Personally I've always laid those bottom orange 2x's flat instead of on edge, just seems more stable, and I screw up into the verticals.

I get what was meant, a leg to floor of some kind keeps from racking or relying on pocket screws, especially w/ that 2x on edge as is, but ply on face would also work for shear strength resolving that.

Absolutely agree. By laying the lumber flat, not only is it more stable but you can send screws straight through it to tie into the vertical corners. Much better in my opionion. Plus gives you a little more height between top and bottom of the openeing. When builing stands remember screwing into end grain is the weakest place for screws to hold, and pocket screws can often times crack and split the board. I always try to avoid both

As others have said. The plywood will keep things from racking. Will be plenty.

 

[TimeTwister]

Dont want to get off topic but what did you use to make your design? (What app or program)

Google sketchup. It's free and relatively simple, but i do recommend watching a few how to videos on youtube to give you the basics first.