Worried that your stand won't hold up?
- Thread starter Pharaoh
- Start date
So 23 load-bearing 2x4s (the purple ones in the diagram) should be enough to hold up a 110, right? 
Overengineering helps me sleep at night.
Overengineering helps me sleep at night.
Maybe I should go for concrete columns instead of the 4x4s? I hear that concrete might just have the compression strength that I'm looking for 
Are you very sure you're looking at the right number? I think you want compression parallel to grain, which is 4,800. Ultimately, it puts your final number at 201,000 lbs.
This thread has been great in the discussion of strength, weight, and spans, but in reading up on stuff before I start assembling my tool collection, I started thinking about stands from another perspective: Wood Movement. So here's my attempt at sparking a few more pages of discussion in this excellent thread.
I'm sure there are probably links that explain that better, and I'm still not totally up on how best to account for this with certain types of joints and cuts (though I now understand why there are so many to accomplish what I previously thought was basically the same thing)... but especially for those of us with sumps underneath, wouldn't this also be a huge consideration for us as stand builders?
I know that whenever I'm carrying 2x4s I notice the slight bending. And that diagram of the tree trunk really illustrates how easily a 2x4 can warp. If we've got a sump with all sorts of surface area underneath, wouldn't that moisture cause all sorts of extra movement and warping/shifting in the 2x4s and 2x6s in our stand frames? How should we account for that? Should we start getting really picky in looking at grains in the boards and only choosing the most central ones? Does painting the inside seal off the wood and make it unable to suck in/release moisture? Am I just trying to create a problem where one doesn't exist?
After reading that article, my brain has started really understanding why people like this guy will scream from the mountaintops that thin plywood is just as reliable as the overbuilt stuff we see here, and how even crappy particleboard can hold a ton of weight. Heck, my first big tank 5 years ago was an old thick-glassed 90g and it sat on what appeared to be nothing more than rotting 1/2" particleboard and glue. (Photo below of when I finally got rid of it, it was basically fraying trim that was breaking away at each joint, but it still held the weight reliably. That top trim piece was the only thing that held the tank, and it's not even supported from below, making me think that some nails were all that bore the weight!) In many ways it seems like plywood is more reliable than the 2x4 frames.
I think having the thick 2x4 gives us all peace of mind and tricks us a bit, and it's certainly plenty strong enough. But if the goal is a true furniture-quality stand, how should one plan for strength AND for avoiding wood movement? If I make a 2x4 skeleton using these ideal plans here then skin it in plywood and nice trim, what steps should also be taken to ensure that all my edges and corners remain perfectly flush and the dimensions consistent? On a table it can expand 1/4" and noone will care, but if it has 2000lbs of inflexible tank on top, there's not really any room for that... is there?
(And on another note - I've yet to have a canopy that didn't eventually warp from all the evaporation. Same questions apply to those - is there any kind of seal/paint for the interior that, when combined with adequate ventilation, can prevent that?)
I'm sure there are probably links that explain that better, and I'm still not totally up on how best to account for this with certain types of joints and cuts (though I now understand why there are so many to accomplish what I previously thought was basically the same thing)... but especially for those of us with sumps underneath, wouldn't this also be a huge consideration for us as stand builders?
I know that whenever I'm carrying 2x4s I notice the slight bending. And that diagram of the tree trunk really illustrates how easily a 2x4 can warp. If we've got a sump with all sorts of surface area underneath, wouldn't that moisture cause all sorts of extra movement and warping/shifting in the 2x4s and 2x6s in our stand frames? How should we account for that? Should we start getting really picky in looking at grains in the boards and only choosing the most central ones? Does painting the inside seal off the wood and make it unable to suck in/release moisture? Am I just trying to create a problem where one doesn't exist?
After reading that article, my brain has started really understanding why people like this guy will scream from the mountaintops that thin plywood is just as reliable as the overbuilt stuff we see here, and how even crappy particleboard can hold a ton of weight. Heck, my first big tank 5 years ago was an old thick-glassed 90g and it sat on what appeared to be nothing more than rotting 1/2" particleboard and glue. (Photo below of when I finally got rid of it, it was basically fraying trim that was breaking away at each joint, but it still held the weight reliably. That top trim piece was the only thing that held the tank, and it's not even supported from below, making me think that some nails were all that bore the weight!) In many ways it seems like plywood is more reliable than the 2x4 frames.
I think having the thick 2x4 gives us all peace of mind and tricks us a bit, and it's certainly plenty strong enough. But if the goal is a true furniture-quality stand, how should one plan for strength AND for avoiding wood movement? If I make a 2x4 skeleton using these ideal plans here then skin it in plywood and nice trim, what steps should also be taken to ensure that all my edges and corners remain perfectly flush and the dimensions consistent? On a table it can expand 1/4" and noone will care, but if it has 2000lbs of inflexible tank on top, there's not really any room for that... is there?
(And on another note - I've yet to have a canopy that didn't eventually warp from all the evaporation. Same questions apply to those - is there any kind of seal/paint for the interior that, when combined with adequate ventilation, can prevent that?)
So I spent some time looking for information on the perpendicular compression strenght of plywood to no luck. I wanted to build my stand for my 240 out of birch ply but could not fin any information on it's perpendicular compression strength so I scrapped it for a 2x4 stand. Now with the work I have put into it I am very satisfied. However I am still looking for information on the strength of plywood.DaveB;4084242; said:
AWESOME JOB Pharao! hCan you PLEASE do the same thing using various gauges and confugurations of mild steel next LOL
