rygh
Guest
3 root 2?
C= sqrt(A*A+B*B)
For 3x3, it is 4.24-ish.
Braces do not have to be particularly diagonal or exact, just put a square on the corners before screwing them on.
Mike's Last Build
- Thread starter sfsuphysics
- Start date
C= sqrt(A*A+B*B)
For 3x3, it is 4.24-ish.
Braces do not have to be particularly diagonal or exact, just put a square on the corners before screwing them on.
sfsuphysics
Supporting Member
I know I was making a math joke, 3,4,5 right triangle is very fundamental to geometry 
sfsuphysics
Supporting Member
Well there was a dumb moment averted, I was going to notch out the dados in the legs because a couple are too small... then I remembered I didn't sand those internal ribs at the corners, a couple had lips, almost all of them had glue that was sticking up.. now everything fits fine.
Ok, I think, I've got my plywood plan. Figure there will be plywood on the top deck where the tank will sit, and on the bottom deck where all the sump and other stuff sits so that plane of movement should be secure, although. Then I'll throw a sheet on one short side that attaches both legs, and then I'll cut a dado in the top and bottom part of those rectangular ribs/frame I made so that should shore up that direction, I don't want to put plywood on the other side because that will be the "fish room" side and I really want access to everything. Then I'll put a sheet right through the center (well off center) to separate the back 2/3rds from the front third, this was the plan all along so I can keep electrical in it's only little area away from any sort of splashing/misting, run it through long dado top and bottom and through some side pieces that hopefully should be enough to stop racking in the 4' long direction, then one piece on the half of the front panel which will should be plenty of strength in that 4' direction.
Gotta say having put in those center legs on the front and back really caused everything to stiffen up since there was that third dado gap to prevent the ends from shifting.
Overall I think I'm good, it's just a matter of knowing which order to do everything, like one of those wooden puzzle boxes, you have to move things in the right order... and hopefully some demon doesn't come out at the end
Ok, I think, I've got my plywood plan. Figure there will be plywood on the top deck where the tank will sit, and on the bottom deck where all the sump and other stuff sits so that plane of movement should be secure, although. Then I'll throw a sheet on one short side that attaches both legs, and then I'll cut a dado in the top and bottom part of those rectangular ribs/frame I made so that should shore up that direction, I don't want to put plywood on the other side because that will be the "fish room" side and I really want access to everything. Then I'll put a sheet right through the center (well off center) to separate the back 2/3rds from the front third, this was the plan all along so I can keep electrical in it's only little area away from any sort of splashing/misting, run it through long dado top and bottom and through some side pieces that hopefully should be enough to stop racking in the 4' long direction, then one piece on the half of the front panel which will should be plenty of strength in that 4' direction.
Gotta say having put in those center legs on the front and back really caused everything to stiffen up since there was that third dado gap to prevent the ends from shifting.
Overall I think I'm good, it's just a matter of knowing which order to do everything, like one of those wooden puzzle boxes, you have to move things in the right order... and hopefully some demon doesn't come out at the end
sfsuphysics
Supporting Member
Welp, officially passed the "Should have spent the extra money and went with aluminum" part of the tank building process, not that I'm terribly upset with the sluggishly slow speed of the build (I mean the tank is going to sit with nothing but rocks and water in it for over a month as it is!), but my kid has decided he wants to hang out with dad more often which is cute and all... but it does restrict the time I get to do any work. So updates were a bit lacking, plus I didn't even take pictures because I figured people didn't care about yet another dado I cut
So I decided enough dry fitting and just glue the damn thing together all ready. The problem was making sure the legs were perfectly vertical, so took me a while to finally catch on, but decided not to do all 4 legs at the same time, instead 3 legs were dry fit, and the 4th was glued in and made sure it was perfectly vertical, then one the glue dried on that went onto the next leg, cross braces were a huge help in "forcing" the issue, once the glue dried it's stuck in that position so we're good to go, then the last too legs which are currently drying
Told my wife about the "pie crust" lattice I made and she just gave me "that look" and asked why so complicated (ties in with the very first line of this post...), I thought about explaining the principle behind a torsion box.. so just walked away.
So now just need to make another "pie crust" for the top, slap some plywood on it, and it's ready for paint.
So I decided enough dry fitting and just glue the damn thing together all ready. The problem was making sure the legs were perfectly vertical, so took me a while to finally catch on, but decided not to do all 4 legs at the same time, instead 3 legs were dry fit, and the 4th was glued in and made sure it was perfectly vertical, then one the glue dried on that went onto the next leg, cross braces were a huge help in "forcing" the issue, once the glue dried it's stuck in that position so we're good to go, then the last too legs which are currently drying
Told my wife about the "pie crust" lattice I made and she just gave me "that look" and asked why so complicated (ties in with the very first line of this post...), I thought about explaining the principle behind a torsion box.. so just walked away.
So now just need to make another "pie crust" for the top, slap some plywood on it, and it's ready for paint.
rygh
Guest
Looking good!
Always best to make it overly complicated. That is what makes life fun.
I don't see a lot of vertical support for the tank though. (the most important part)
Just the wood stuck in those little dado slots?
Or is there another top layer.
Aluminum would have its share of issues as well...
Always best to make it overly complicated. That is what makes life fun.
I don't see a lot of vertical support for the tank though. (the most important part)
Just the wood stuck in those little dado slots?
Or is there another top layer.
Aluminum would have its share of issues as well...
sfsuphysics
Supporting Member
There are vertical pieces on the front and back in the middle, I'm trying to save those for last so sliding the sump is easier, although now that I think of it I kind of want to paint it before putting in the sump but then I can't put the sump in if everything is together... it's a huge catch-22... I guess I could paint the middle leg in the back then secure it in after I put in the sump.
The horizontal "boxes" (top and bottom) are just stuck into the dado slots yeah, I refer to them as "ribs" their main purpose is to hold all the legs secure and prevent any twisting in those two directions, the bottom one will also serve as the base for inside the tank (sump/equipment/etc). The tank weight itself will not be resting directly on these, also a place to hide/attach wires above everything.
There will be another layer on the very top (the torsion box briefly mentions in the above post), this will hold the tank and and then be the last bit to secure all the legs together, not sure how I'll attach it, this is where I'm thinking mortise and tenon joints... but the idea of lining up all 6 legs so they all fit perfectly kind of worries me... so I might just screw it to the top of the legs and be happy with the internal rib structure holding it all together.
The horizontal "boxes" (top and bottom) are just stuck into the dado slots yeah, I refer to them as "ribs" their main purpose is to hold all the legs secure and prevent any twisting in those two directions, the bottom one will also serve as the base for inside the tank (sump/equipment/etc). The tank weight itself will not be resting directly on these, also a place to hide/attach wires above everything.
There will be another layer on the very top (the torsion box briefly mentions in the above post), this will hold the tank and and then be the last bit to secure all the legs together, not sure how I'll attach it, this is where I'm thinking mortise and tenon joints... but the idea of lining up all 6 legs so they all fit perfectly kind of worries me... so I might just screw it to the top of the legs and be happy with the internal rib structure holding it all together.
xcaret
Guest
Welp, officially passed the "Should have spent the extra money and went with aluminum" part of the tank building process, not that I'm terribly upset with the sluggishly slow speed of the build (I mean the tank is going to sit with nothing but rocks and water in it for over a month as it is!), but my kid has decided he wants to hang out with dad more often which is cute and all... but it does restrict the time I get to do any work. So updates were a bit lacking, plus I didn't even take pictures because I figured people didn't care about yet another dado I cut
So I decided enough dry fitting and just glue the damn thing together all ready. The problem was making sure the legs were perfectly vertical, so took me a while to finally catch on, but decided not to do all 4 legs at the same time, instead 3 legs were dry fit, and the 4th was glued in and made sure it was perfectly vertical, then one the glue dried on that went onto the next leg, cross braces were a huge help in "forcing" the issue, once the glue dried it's stuck in that position so we're good to go, then the last too legs which are currently drying
Told my wife about the "pie crust" lattice I made and she just gave me "that look" and asked why so complicated (ties in with the very first line of this post...), I thought about explaining the principle behind a torsion box.. so just walked away.
So now just need to make another "pie crust" for the top, slap some plywood on it, and it's ready for paint.
You know you can always make a nice coffee table out of it if you go Aluminum...
rygh
Guest
Thoughts:
Put your sump in last by making the TOP removable.
So do all the sides, legs, and so on.
Then the top part just screws down to the legs after sump is in.
For the top part:
Screw+Glue the plywood top to your fancy torsion box tightly.
That will give you a really solid flat surface.
If you want to get really fancy and strong, glue another thin piece of plywood on the other side.
Put your sump in last by making the TOP removable.
So do all the sides, legs, and so on.
Then the top part just screws down to the legs after sump is in.
For the top part:
Screw+Glue the plywood top to your fancy torsion box tightly.
That will give you a really solid flat surface.
If you want to get really fancy and strong, glue another thin piece of plywood on the other side.
rygh
Guest
sfsuphysics
Supporting Member
I'm still leaning towards removable middle/back leg (not pictured), people do this on other designs (often the front middle because it's squished against a wall). The sump will not be as wide as the outside legs so I should be able to remove if necessary, but seriously guys, removable sump due to leaks? Talk about shooting yourself in the foot for a just incase issue, besides if my sump leaks I'm taking a chop saw to it and I'll remove it that way if necessary, no sense in reusing a broken sump because I think I might be able to get some more life out of it, or I could chop out the side plywood (although that will be glued in so considerably more work) and the sump is going to be fairly massive under the tank, so there's really no upgrade direction. Or hell one side of the stand won't have plywood, there's 36" between the stand and the wall and the sump will be somewhere in the neighborhood of 42-44" long so I can slide it out at an angle if absolutely necessary and then I don't need to make anything removable... however the sump is going to be friggin heavy... I found a useage for all that 1" thick acrylic I got when Ocean Treasures when out of business
And yes, plywood on top and bottom is what makes it a torsion box and gives it it's rigidity, otherwise there's no compression strength for the flex in the other direction.
And yes, plywood on top and bottom is what makes it a torsion box and gives it it's rigidity, otherwise there's no compression strength for the flex in the other direction.
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sfsuphysics
Supporting Member
Well the sump won't be as tall as I want the tank to stand
Torsion box doesn't have to be thin strips of wood, all it has to do is have some core which isn't isn't completely solid (i.e. hollow voids this is for weight issues... you could have a completely solid core I guess) with plywood on either side that is attached to that core that provide both compression and tension forces along every part, kind of like an I-beam but in 2 directions instead of one. The reason why strips of wood are often used (e.g. doors) is because it allows a shift of the material to add puncture strength over the surface, where as mine with have rather large voids with thicker stock, if you were to make say a workbench you'd want thin strips that are more closely spaced (similar weight probably) to if you hammer something on your worktop you won't accidentally punch a hole through it, for my case I don't need that puncture resistance as it will be a static load on the top, and the weight will all be distributed over solid wood anyways, the plywood is simply going to give it a bit added stiffness to resist deflections. The plywood for sides is for the actual stand proper, not the stand's top.
Heck if you read some of those reef central threads on "simply tank stand" people suggest 2x6 (sometimes 2x6) beams to deal with deflection issues which seems like super overkill when a couple sheets of thin plywood could achieve the same goal with much smaller stock.
Torsion box doesn't have to be thin strips of wood, all it has to do is have some core which isn't isn't completely solid (i.e. hollow voids this is for weight issues... you could have a completely solid core I guess) with plywood on either side that is attached to that core that provide both compression and tension forces along every part, kind of like an I-beam but in 2 directions instead of one. The reason why strips of wood are often used (e.g. doors) is because it allows a shift of the material to add puncture strength over the surface, where as mine with have rather large voids with thicker stock, if you were to make say a workbench you'd want thin strips that are more closely spaced (similar weight probably) to if you hammer something on your worktop you won't accidentally punch a hole through it, for my case I don't need that puncture resistance as it will be a static load on the top, and the weight will all be distributed over solid wood anyways, the plywood is simply going to give it a bit added stiffness to resist deflections. The plywood for sides is for the actual stand proper, not the stand's top.
Heck if you read some of those reef central threads on "simply tank stand" people suggest 2x6 (sometimes 2x6) beams to deal with deflection issues which seems like super overkill when a couple sheets of thin plywood could achieve the same goal with much smaller stock.
Mr. Ugly
Past President
Yep. I did a torsion box from 2x skinned with 1/4” ply when I had my 150.
sfsuphysics
Supporting Member
Alright, first mistakes done.
Can't see it?
Here's another couple shots.
Yup, the leg is rotated out of whack... I designed this so the long side would go on the short side of the stand, this is because that side is not supported in the middle like the front (long) stand side. The upside is the notches I cut are symmetrical so everything fit together fine, I really doubt it'll make THAT much difference in strength. However having glued it in means that it ain't going anywhere, if I had 100% glue adhesion there's like 20000 pounds required to rip that free, so yeah it's there for the long haul unless I cut it off which is an option, but at this point I don't want to do that, this will simply be that tiny scratch that no one will ever notice except me and it will bug the crap out of me.
Now the good news is I got the top about 75% done!
Nice interlocking beams
But I wasn't particularly happy with the open ends, so I blocked them off as well...
I <HEART> WAFFLES!
Here's where strength comes into play, spread glue all over the beams, then used screws to make sure everything was smooshed down.
TADA! Going to let the glue dry up over night, which isn't absolutely necessary but the wife wants some alone from baby time So it's a good enough time to stop.
Glue is good stuff too, this glue has a bonding strength of 4000psi, and if you add up all the area that's in contact that's somewhere on the order of 4 million pounds! This is in the horizontal plane which helps the tensile strength of the top making it stiffer, tomorrow I'll throw a sheet on the bottom and really turn it into a solid slab. Now this doesn't mean it can takes 4 million pounds of tensile strength before it fails because the wood will fail before the glue does, but still good to know it'll take a lot to rip this thing apart.
Can't see it?
Here's another couple shots.
Yup, the leg is rotated out of whack... I designed this so the long side would go on the short side of the stand, this is because that side is not supported in the middle like the front (long) stand side. The upside is the notches I cut are symmetrical so everything fit together fine, I really doubt it'll make THAT much difference in strength. However having glued it in means that it ain't going anywhere, if I had 100% glue adhesion there's like 20000 pounds required to rip that free, so yeah it's there for the long haul unless I cut it off which is an option, but at this point I don't want to do that, this will simply be that tiny scratch that no one will ever notice except me and it will bug the crap out of me.
Now the good news is I got the top about 75% done!
Nice interlocking beams
But I wasn't particularly happy with the open ends, so I blocked them off as well...
I <HEART> WAFFLES!
Here's where strength comes into play, spread glue all over the beams, then used screws to make sure everything was smooshed down.
TADA! Going to let the glue dry up over night, which isn't absolutely necessary but the wife wants some alone from baby time
So it's a good enough time to stop.Glue is good stuff too, this glue has a bonding strength of 4000psi, and if you add up all the area that's in contact that's somewhere on the order of 4 million pounds! This is in the horizontal plane which helps the tensile strength of the top making it stiffer, tomorrow I'll throw a sheet on the bottom and really turn it into a solid slab. Now this doesn't mean it can takes 4 million pounds of tensile strength before it fails because the wood will fail before the glue does, but still good to know it'll take a lot to rip this thing apart.
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sfsuphysics
Supporting Member
Thanks Eric
Torsion box top is done, no pictures because it looks just like above, except with a bottom piece of plywood that you can't see anyways. Gotta say it got heavy in a hurry with two sheets of 1/4" added... or maybe it just got bulkier to move since I couldn't grab in the middle anymore.
And since Mark complained in his thread I'll complain in mine, was firing off a set of dados for 1/4" ply to slide into to make it look all clean and done, and wouldn't you know... damn router bit snapped on me, tried to finish it up with a 1/8" bit and make two passes, and that snapped on me too, I'll take blame on the second one since I was using it like it was a 1/4" bit. Managed to fish through some really old tools in my garage and found a bit that kind of works, it's quarter inch bit, but has a pointed nose instead of a straight bevel, it seemed to work.
So if all goes well tomorrow, I can start sliding plywood into place and call this stand done... and by done I mean I still need to paint it. The reality though is as more plywood goes in it means I have to think more about how things get cut and put in, so not holding my breath that tomorrow will be done day.
Torsion box top is done, no pictures because it looks just like above, except with a bottom piece of plywood that you can't see anyways. Gotta say it got heavy in a hurry with two sheets of 1/4" added... or maybe it just got bulkier to move since I couldn't grab in the middle anymore.
And since Mark complained in his thread I'll complain in mine, was firing off a set of dados for 1/4" ply to slide into to make it look all clean and done, and wouldn't you know... damn router bit snapped on me, tried to finish it up with a 1/8" bit and make two passes, and that snapped on me too, I'll take blame on the second one since I was using it like it was a 1/4" bit. Managed to fish through some really old tools in my garage and found a bit that kind of works, it's quarter inch bit, but has a pointed nose instead of a straight bevel, it seemed to work.
So if all goes well tomorrow, I can start sliding plywood into place and call this stand done... and by done I mean I still need to paint it. The reality though is as more plywood goes in it means I have to think more about how things get cut and put in, so not holding my breath that tomorrow will be done day.
sfsuphysics
Supporting Member
Did the last bits of cutting today, and slid it all together. Need to glue it together, and fill a couple holes, and get some trim pieces to cover imperfections, but other than that, ready for primer and paint. Also need to order some strong magnets since that's the way the front doors/panels are going to attach.
My nice big open space... no longer so open.
My nice big open space... no longer so open.