Input please

[Justfebreezeit]

This has the 2x6 in the right place. I don't think you need them all the way around, just the front peice spanning the 48" gap you need.

Edit: ignore everything else about the stand obviously.

 

[reefer2/19/24]

I’m constructing a stand out of 2x4’s for a 240 gallon tank. I’ve done one before and it worked out good however I now need to construct one for an opening to accommodate a 4’ long sump. I plan to hide it behind a panel out of view. How many cross braces should I use? I’m asking because now instead of having a 2.5 ft cabinet at each end, I now need to have a 4’ opening in the fromt and center stand. I will be covering the entire top with 3/4 “ plywood. Should I sister the top center braces? Tanks in advance!

Don't sister 2'x4' to weak. I get it's 4' long how about fitting (slide it through the end of the stand instead of the front? That would also allow for more vertical bracing. Just a thought from an old carpenter.

 

[N2deep2025]

This has the 2x6 in the right place. I don't think you need them all the way around, just the front peice spanning the 48" gap you need.

Edit: ignore everything else about the stand obviously.

Does that 2x6 brace allow me to then move the two pieces I marked in black to 50” apart in the center of the tank stand?

 

[Justfebreezeit]

Does that 2x6 brace allow me to then move the two pieces I marked in black to 50” apart in the center of the tank stand?

Yes that's the idea.

 

[RocketEngineer]

Yes, that’s exactly what I had meant to explain. Sorry for the confusion.

 

[BeanAnimal]

Beam Calculator – Second Moment and Deflection | BeanAnimal's Reef

There is an accompanying article too...

The deflection calculation is very straight forward. Have fun :)

Use uniform load for the span you wish. Calculate the section weight based on the entire weight of ~10 pounds per gallon. Figuring out the load over the span is also straight forward, based on the length of the span as a fraction of the perimeter. Hope that makes sense.

 

[N2deep2025]

Yes that's the idea.

Now I understand!!!!! Thank you!

 

[N2deep2025]

Now I understand!!!!! Thank you!

One more question (right) I have chosen to go with 2x8 as I was pushing the limits with the 2x6 according to The Sagulator. Lumber yard 10 min from my home and better prices for non stud grade, premium. Question is If I do go with 2x8 for all but the bottom, can I use 2x4” for the base?

 

[BeanAnimal]

The base really does not matter.

I have not look at the “sagulator” in decades and am. Of sure if the math is right or not. I would check the output against the calculator that I posted above. I know the results are correct.

2x8 legs are likely overkill by several magnitudes for a vertical load and the stand needs to have shear support anyway for lateral loading.

 

[N2deep2025]

The base really does not matter.

I have not look at the “sagulator” in decades and am. Of sure if the math is right or not. I would check the output against the calculator that I posted above. I know the results are correct.

2x8 legs are likely overkill by several magnitudes for a vertical load and the stand needs to have shear support anyway for lateral loading.

Not sure what is meant by shear support. Oddly the original stand is from 2x4’s and has held up extremely well. The only reason I’m changing is due to the current stand does not have accommodations for a 4’ sump thus there will be a 4’ space to the center where as is a 2’. Thanks everyone for all the help and input.

 

[Justfebreezeit]

I'm completely out of depth in structural engineering but having 8 total verticals makes alot of visual sense

 

[N2deep2025]

I'm completely out of depth in structural engineering but having 8 total verticals makes alot of visual sense

My bad, I forgot to draw those in but have them included in my head.

 

[Marco_99]

Not sure what is meant by shear support. Oddly the original stand is from 2x4’s and has held up extremely well. The only reason I’m changing is due to the current stand does not have accommodations for a 4’ sump thus there will be a 4’ space to the center where as is a 2’. Thanks everyone for all the help and input.

Shear support as in meaning wrapped with a ply board