How much weight can a doubled up 2x4 hold?

[Jeff000]

It won't rack. Only way for it to rack, is one end go up the other down. The other end is already down........to get it to go over you have to pick the other end up. Understand now?

Stand you built here looks good, but it is excessive overkill, but there really isn't anything reasonable about excessive overkill, it is simply excessive. The Plywood box is overkill.

What remains, since the stand is not finished yet, is whether it will come up flat, plumb, level--after the dimensions change with temperature and humidity, causing the thing to display a short end, twist, or other anomaly, which is the subject of too many DYI stand threads.

Ah ok.

All the wood has been in my basement for 6 months. Of the 40 or so boards, these were the only ones that were still straight. Despite me hand picking all straight boards from the pile. So hopefully they will not warp any. But if they do I'm hoping the rest of the stand will hold it level still.

 

[uncleof6]

It is not the bow that will get you as much as the length dimension change, since it is cut to size now.......

 

[Jeff000]

It is not the bow that will get you as much as the length dimension change, since it is cut to size now.......

How much could it change?

 

[uncleof6]

Enough to mysteriously show up as a 1/16" - 1/8" gap at one end of the stand...or worse at both ends, creating a hump in the middle. Add that to uneven crook in the top rim pieces, or the crook pointed up....Sound familiar? "I measured three times, cut them all the same, but the stand is out of whack......" The most common lumber stand problem.

Green wood will shrink, kiln dried will expand. Bench jointer to deal with the crook. Humidity control to deal with dimensional changes.

 

[Jeff000]

Enough to mysteriously show up as a 1/16" - 1/8" gap at one end of the stand...or worse at both ends, creating a hump in the middle. Add that to uneven crook in the top rim pieces, or the crook pointed up....Sound familiar? "I measured three times, cut them all the same, but the stand is out of whack......" The most common lumber stand problem.

Green wood will shrink, kiln dried will expand. Bench jointer to deal with the crook. Humidity control to deal with dimensional changes.

Hmm, ok.
Climate wise nothing should change much. But I will keep an eye on things.

The pressure treated has already shurnk. It's 2 years old.

 

[mcgyvr]

Compression strength (parallel to grain) of "typical" US Spruce is roughly 5,000 PSI
A 2x4 is 5.25 sq in.
5.25 x 5000 = 26,250 lbs in compression


I'd take an over built stand over an under built one ANY day.. Wood is cheap build away the worry..
You never know when a stripper or whatever is gonna jump up on it and wanna dance.

 

[uncleof6]

That is just the thing mcgyvr, a plywood box is overbuilt. And with nothing else other than the plywood, will not rack over when the dancers jump up on it, no need for additional wood to keep it from doing so. Even those with a knowledge of the strength of wood, have a hard time getting their mind around the fact that a plywood box is overbuilt. The loads presented by these tanks are nothing--small loads.