My idea for a DIY plywood aquarium
- Thread starter Big Fish Freak
- Start date
So I have been spending all this time on the idea for the tank that I seem to have overlooked a pretty inportant part of the build...the stand!!!
Not really but I feel like it could use some attention in this thread.
My first question is this:
Should I spend the extra $$ and get 4x4s and use those as the vertical supports? Or is doubling up 2x4s just as strong? And what is the best way to maximize support but also have room for the sump..this is going to be the part that will hold me up the most with the build.
Not really but I feel like it could use some attention in this thread.
My first question is this:
Should I spend the extra $$ and get 4x4s and use those as the vertical supports? Or is doubling up 2x4s just as strong? And what is the best way to maximize support but also have room for the sump..this is going to be the part that will hold me up the most with the build.
About using 4x4's.... If you get pressure treated 4x4's, often they'll be very wet, so they tend to warp, twist, or split later on since they aren't kiln dried. Douglas Fir Kiln Dried 4x4's can be nice to work with, but they cost more, and can be more difficult to fabricate than 2x4's. You may need to make at least 2 passes with a circular saw to cut a 4x4. Douglas Fir is quite hard for a softwood also, so screwing into it sometimes isn't easy. It's hardness is enough to break drywall screws (el cheapo) and may strip the screw heads off most others. So it makes you want to drill extra large pilot holes. If you screw and glue everything, and no structural load is on the screws, then that shouldn't matter. Douglas Fir 4x4 is a great lumber for bolts and lag bolts, if you are building a monster stand and have an impact wrench.
2x4's are much easier to work with. Easy to cut and easy to screw into. Selecting 2x4's from the pile at the big box store can be a big headache though. At least for me it is. Finding pieces that are straight and where the end grain looks quartersawn is sometimes impossible. So you just have to take the best you can find in the pile and try not to be too anal. Plywood is the same way. I get very discouraged with all the core voids I see in sanded plywood, so I usually step it up and get birch plywood. I'll be picking through the birch plywood also, where sometimes I'll have to sort through a dozen pieces just to find a piece that I like. If I'm paying around $50 for a sheet of plywood, it better be furniture grade. I just can't be in hurry when I'm buying lumber.
2x4's are much easier to work with. Easy to cut and easy to screw into. Selecting 2x4's from the pile at the big box store can be a big headache though. At least for me it is. Finding pieces that are straight and where the end grain looks quartersawn is sometimes impossible. So you just have to take the best you can find in the pile and try not to be too anal. Plywood is the same way. I get very discouraged with all the core voids I see in sanded plywood, so I usually step it up and get birch plywood. I'll be picking through the birch plywood also, where sometimes I'll have to sort through a dozen pieces just to find a piece that I like. If I'm paying around $50 for a sheet of plywood, it better be furniture grade. I just can't be in hurry when I'm buying lumber.
I did not know that about 4x4's..probably cause I've never worked with them before but that's beside the point..unfortunately I am really anal about stuff..its just one of the things my dad left as an imprint in my head..but it has worked out nicely for me..everything I own looks brand new and has lasted much longer than the same thing in another persons hands..it takes me hours to go through 2x4s!!! I havent really had the same problem with plywood but I'm sure now that you mentioned it, I am gonna pay a little more attention to it..with what is gonna end up with the wood I'm sure it really wont matter how straight it is, (to a degree) but I am unfortunately an anal perfectionist when it comes down to the way everything looks..it all has to have the same grain and be going the same way so it looks nice..lol
That is another good thing to talk about..how long should my screws be that help hold the box together? 2", 2 1/2"? Bigger? And also, would it be better to start with sanded ply since i'm gonna need to sand it for fiberglassing and epoxy? Or does that matter? I know the snded ply at my HD is like really smooth, but i thought you wanted a more coarse finish to let the epoxy bite into?
That is another good thing to talk about..how long should my screws be that help hold the box together? 2", 2 1/2"? Bigger? And also, would it be better to start with sanded ply since i'm gonna need to sand it for fiberglassing and epoxy? Or does that matter? I know the snded ply at my HD is like really smooth, but i thought you wanted a more coarse finish to let the epoxy bite into?
For 2x4 stand I used #8x 2-1/2" GripRite Primeguard Ten Exterior Screws, which cost about $24 for a 5# box (430 count) at Home Depot.
For plywood box I used #8x 2" Spax Construction Screws, which cost about $11 for 300 count at Menards.
The GripRite's are a heavier and higher quality screw, but for a plywood box I didn't think the extra strength mattered much since I spaced the screws every 3" and used epoxy to permanently hold the joints together.
Recently bought some excellent screwdriver bits that wish I had earlier for my tank build. Got the Dewalt MaxFit #2 screwdriver bits with a 10x magnetic screw lock sleeve. Screw-heads fit bit like a glove. I'll be tossing out my old set of screw bits.
Sanded ply will work fine. For me, lately it's just been hard to find some that's any good. Most of the sanded stuff I see looks more like sheathing. My blood pressure goes up just thinking about it. 20 years ago, the cheap sheathing looked better than the sanded ply I'm seeing these days. You'll just have to repair any visible core voids / imperfections if you have any. For the repairs, I'd use Max Bond or sawdust mixed with Epoxy, instead of Bondo or wood filler since they aren't waterproof.
For plywood box I used #8x 2" Spax Construction Screws, which cost about $11 for 300 count at Menards.
The GripRite's are a heavier and higher quality screw, but for a plywood box I didn't think the extra strength mattered much since I spaced the screws every 3" and used epoxy to permanently hold the joints together.
Recently bought some excellent screwdriver bits that wish I had earlier for my tank build. Got the Dewalt MaxFit #2 screwdriver bits with a 10x magnetic screw lock sleeve. Screw-heads fit bit like a glove. I'll be tossing out my old set of screw bits.
Sanded ply will work fine. For me, lately it's just been hard to find some that's any good. Most of the sanded stuff I see looks more like sheathing. My blood pressure goes up just thinking about it. 20 years ago, the cheap sheathing looked better than the sanded ply I'm seeing these days. You'll just have to repair any visible core voids / imperfections if you have any. For the repairs, I'd use Max Bond or sawdust mixed with Epoxy, instead of Bondo or wood filler since they aren't waterproof.
All good things to know Keith. I couldnt imagine being the first person to build one of these things..too many questions come to mind..
So I got a call from my buddy at a glass shop and they have a "scrap" piece of glass they said they could make me a deal on..it's tempered glass, and it fits the dimensions I need for the window, the only concern I have is that it is 1/2"...would 1/2" tempered glass be plausible, or is it too much of a risk?
It would be really sweet to score a piece of glass for dirt cheap, but not sweet to have that cheap glass be the reason for 900 gallons of water to flood my garage...I think I already know the answer I am gonna get, but seeing as how glass isn't my strong point, I figured i would put it up here for someone with more experience to give me a more shatterproof explanation
So I got a call from my buddy at a glass shop and they have a "scrap" piece of glass they said they could make me a deal on..it's tempered glass, and it fits the dimensions I need for the window, the only concern I have is that it is 1/2"...would 1/2" tempered glass be plausible, or is it too much of a risk?
It would be really sweet to score a piece of glass for dirt cheap, but not sweet to have that cheap glass be the reason for 900 gallons of water to flood my garage...I think I already know the answer I am gonna get, but seeing as how glass isn't my strong point, I figured i would put it up here for someone with more experience to give me a more shatterproof explanation
Also, for this size tank, when building the stand, what is the biggest I should have for a span between braces? I plan on putting 1 brace every 12" on the short side, so I will have a total of 5 vertical supports on one of the short sides, the other will have 4 to make room for the plumbing. What should I do for the long sides though? I do need to access the bottom for the sump, so I was thinking maybe a brace every 2' or maybe just do a double brace every 2' ?
On the top where the tank will sit I was thinking of doing braces in both directions like if you were building a deck, but would just going from front to back be fine if I had enough of them?
The stand will be wrapped in ply for added stability, so I should be fine there...Just gotta get the support beams mapped out...
On the top where the tank will sit I was thinking of doing braces in both directions like if you were building a deck, but would just going from front to back be fine if I had enough of them?
The stand will be wrapped in ply for added stability, so I should be fine there...Just gotta get the support beams mapped out...
Everyone will have there own idea's on how to build a stand. I need to design my stands so that they're portable and strong enough to be on an uneven floor. My stands need to be shimmed up every few feet, so I double the strength of the stands. Will your stand be on a flat concrete slab or an uneven wood floor?
I'd try to design the stand to make things as easy as possible. What is the ideal total height of the tank and stand together so that you can do tank maintenance and be able to transport fish? In some big tanks, it's just too difficult to work on a sump that's underneath the tank. So the filtration might go behind the tank in a more accessible area. Transporting an Arapaima or other big fish will be challenging. Don't think you can do that from outside the tank while standing on a ladder with a big net. You'll probably have get inside the tank. You may have to build some kind of portable platform with stairs to get in and out of the tank. There's a lot to think about to make life easier. The stand doesn't have to be wood, does it? For a 3 foot high tank with 8' x 5' footprint, maybe I'd be thinking about a cinder block stand that's about 16" high off the ground.
I'd try to design the stand to make things as easy as possible. What is the ideal total height of the tank and stand together so that you can do tank maintenance and be able to transport fish? In some big tanks, it's just too difficult to work on a sump that's underneath the tank. So the filtration might go behind the tank in a more accessible area. Transporting an Arapaima or other big fish will be challenging. Don't think you can do that from outside the tank while standing on a ladder with a big net. You'll probably have get inside the tank. You may have to build some kind of portable platform with stairs to get in and out of the tank. There's a lot to think about to make life easier. The stand doesn't have to be wood, does it? For a 3 foot high tank with 8' x 5' footprint, maybe I'd be thinking about a cinder block stand that's about 16" high off the ground.
Personally I would avoid tempered. You see tanks all the time that crack. If that was ever a tempered piece it would be all she wrote. Also static load does weird things to tempered... with pressure put on it just the slightest anything sometimes make them explode.
The stand is going on a flat concrete slab in my garage..this whole tank is planned out to be easy, so I am not worried about having to work under it..I am looking forward to getting in the tank to clean it or move stuff around in it
The cinder block stand isn't too much of a bad idea. Would I just structure it like I would a wooden stand? That makes the cost about 1/3 of a wooden stand based on the same design I have for my stand. Would I bond the blocks together with mortar or just stack em? Stacking them would make the stand very portable. And would I lay them on the 8" side with the holes horizontal or on the 6" side with the holes vertical?
