1500 Gallon Plywood Project....

[Rivulatus]

I'm in the planning stages of a (roughly) 1500 gallon tank. Plywood. In researching, I happened to come across this fella's plans, and I'm using them as a concept for my project:

http://www.jonolavsakvarium.com/eng_diy/2200litre/2200litres.html

Drywall, on paper anyway, will eventually hide the god awful lag screws and washers around the front glass, so...

To set you up for my question, I'm considering framing what amount to walls with 1" grade A plywood and gluing/lagging them, construcing in essence a very sturdy beamed frame and box, such as this guy did. I've defaulted to the idea of a number of layers of epoxy with two base layers of chopped strand fiberglass matting in all of the joints. Once everything is dry and I have approximately six layers of expoy on the inside, I considered then siliconing the joints, with the thought that perhaps if the fiberglass joints crack at all from any minute (hopefully minute!) shifting or settling, the silicone might flex and still provide a seal.

Fast forward to today: I was chatting with a friend tonight, and he proposed the possibility of using PVC shower and tub wall surround panels...screwing or gluing them to the 1" plywood sheets already used for the walls. Lay two base layers of chopped strand fiberglass matting and epoxy on the plywood seams first, then apply the PVC panels, and then silicone the joints.

Does anyone have any anwers or thoughts as to whether the shower surround material might in some way harm the livestock?

Or any suggestions or thoughts on the construction of the tank in general? I've considered one possibility of air bubbles in the glue and the panels not being completely flush and flat to the surface, then flexing with the force of 13,000 pounds or so of water and cracking the joints....

This started out being that I was going to just buy a 500 to 710 gallon tank. In considering the weight of it, and in measuring doorways and angles, I realized we would never get it downstairs. So I thought I would research building something. It's cheaper, perhaps, and if you're going to build it, you might as well do it right. Of course, six tons or better of water and the associated pressure.... This concerns me a bit. I'm certainly not the most saavy DIYer.

I've a bit of experience with aquaria, have kept fresh and saltwater fish, have a tank dedicated to our Motoro Ray, have modified our 125 gallon saltwater tank and plumbed a sump for it, etc. None of that really matters where this project is concerned, however, and I've constructed only one tank in the past--a tiny frameless all glass 20 gallon aquarium. So, I'm certainly open for thoughts.

Thanks for any insight, all!

Jason

 

[Finalfire9]

If your makin a tank that big dont mess around build a frame of wood and pour the sides of your tank with quickcrete. Be sure to make it a single cast then remove your wood frame when dry. Then spray it all with a latex coating.

 

[bbrtmad]

I think it might work im kicking around the idea of building a 1000 plus gal tank and using 1/4" plexi on the inside bottom back and sides then sealing it with glue and silicone. But i might use fiberglass just depends on whats more cost effective.

 

[Rivulatus]

If your makin a tank that big dont mess around build a frame of wood and pour the sides of your tank with quickcrete. Be sure to make it a single cast then remove your wood frame when dry. Then spray it all with a latex coating.

I've considered that, as well. I have zero concrete experience, however, and to have a contractor frame and pour is a bit costly. I haven't completely ruled it out yet, though.

Thanks for the suggestion, Finalfire!

 

[Rivulatus]

I think it might work im kicking around the idea of building a 1000 plus gal tank and using 1/4" plexi on the inside bottom back and sides then sealing it with glue and silicone. But i might use fiberglass just depends on whats more cost effective.

Good idea! Plexi glass is probably a good alternative if you're going to attach something to the plywood and seal the joints.

In calling around and researching online, I've concluded so far that polyvinyl chloride, not ABS, would be safe to use. However, it is incredibly expensive, even for an 1/8" thick sheet in the size that I would need: 96" X 54", and besides that, I can only find it sheets of 8' X 4'.

Being new to this, of course, I think perhaps a critical factor is building a sturdy enough "box." Framing, gluing, lagging, using 1" thick plywood, 1" thick front glass, and strong framing wood (such as douglas). If there is miniscule settling and flex, I think fiberglassing the joints and then eventually siliconing them should prove reliable. Although, longterm, I wonder.... Makes you consider a thick pond liner, as well, but I wonder about tearing with all of that pressure. It appears that other folks have had success with them, but I don't have much confidence.

I see on MFK many other fellas have built much bigger tanks that 1500 gallons, and they used epoxy coating with fiberglass in the seams. I think I'll stick with that and see how my prototype 400 gallon tank works out! If it works out, I'll modify it to use as my sump.

Thank goodness for my step-father and good friends.

Any other thoughts or suggestions are welcomed guys!

Jason

 

[loogielv]

i'm always amazed at how people for some reason abandon what has proven to work for any reason other than necessity.

not slamming anyone in this thread or anything, i'm just curious why people over analyze and dont trust what has proven to work. Some people have built plywood/expoxy tanks back in the 70s that are still working. And that was before we know what we do now.

IMO, adding any acrylic, or cement or hardi panels or anything of the sort is not only unnecessary, but cost prohibitive and in my honest and humble opinion, merely a way to add more points of failure.

I dont believe you even need fiberglass when making a tank like this. Sure it'll help, and it's one of the only additions to a build i would recommend, but I dont believe it'll make or break the build.
With proper bracing around the sides I dont even see why you'd need 1" plywood.
Dont overbuild, over engineer. It'll save you boatloads of cash and provide those that come after you some peace of mind in knowing a minimilistic approach does not equal failure.

I saw a guy build a 500 gallon, 10 ft long tank. He joined 2 pieces of plywood together (certainly a plywood tank "nono") He had NO bracing around the tank. Only the plywood. He didn't even use screws. He used all glue. (he might've used some screws, but i dont remember for sure. I know all the brackets and crossbracing was all with glue) He only fiberglassed the seams. He poured the epoxy straight onto the wood and spread it around. All things that are considered underbuilding.

Sorry, not trying to get onto a soapbox tangent, It's just my opinion that adding anything other some 2x4's for bracing about ever 8 or 10 inches, some 3/4" plywood and a boatload of expoxy is not necessary.
If you're really worried about the seams, consider adding a 2"x2" strip, ripped in half at a 45 degree angle (making a triangle basically) glue over the seam and seal over that. That will help alleviate some pressure on the joints and also will take away direct water access to the seam. A solid engineering design with minimilistic impact on the tank, and the budget.

It is my opinion you're right on the money with the expoxy (and fiberglass) as well as using the bolts to secure some of the bracing. Go for it!

Also, may i suggest severly underbuilding the 400gallon test tank. put nothing in "for peace of mind" just build it as if you don't care if lasts a week, but would prefer that it did.
You'll see that it will last, and you'll have much better sleep when you build the monster!

 

[Rivulatus]

i'm always amazed at how people for some reason abandon what has proven to work for any reason other than necessity.

not slamming anyone in this thread or anything, i'm just curious why people over analyze and dont trust what has proven to work. Some people have built plywood/expoxy tanks back in the 70s that are still working. And that was before we know what we do now.

IMO, adding any acrylic, or cement or hardi panels or anything of the sort is not only unnecessary, but cost prohibitive and in my honest and humble opinion, merely a way to add more points of failure.

I dont believe you even need fiberglass when making a tank like this. Sure it'll help, and it's one of the only additions to a build i would recommend, but I dont believe it'll make or break the build.
With proper bracing around the sides I dont even see why you'd need 1" plywood.
Dont overbuild, over engineer. It'll save you boatloads of cash and provide those that come after you some peace of mind in knowing a minimilistic approach does not equal failure.

I saw a guy build a 500 gallon, 10 ft long tank. He joined 2 pieces of plywood together (certainly a plywood tank "nono") He had NO bracing around the tank. Only the plywood. He didn't even use screws. He used all glue. (he might've used some screws, but i dont remember for sure. I know all the brackets and crossbracing was all with glue) He only fiberglassed the seams. He poured the epoxy straight onto the wood and spread it around. All things that are considered underbuilding.

Sorry, not trying to get onto a soapbox tangent, It's just my opinion that adding anything other some 2x4's for bracing about ever 8 or 10 inches, some 3/4" plywood and a boatload of expoxy is not necessary.
If you're really worried about the seams, consider adding a 2"x2" strip, ripped in half at a 45 degree angle (making a triangle basically) glue over the seam and seal over that. That will help alleviate some pressure on the joints and also will take away direct water access to the seam. A solid engineering design with minimilistic impact on the tank, and the budget.

It is my opinion you're right on the money with the expoxy (and fiberglass) as well as using the bolts to secure some of the bracing. Go for it!

Also, may i suggest severly underbuilding the 400gallon test tank. put nothing in "for peace of mind" just build it as if you don't care if lasts a week, but would prefer that it did.
You'll see that it will last, and you'll have much better sleep when you build the monster!

I don't take any of what you said as a slam or a personal affront. I really appreciate your input and suggestions!

I over analyze and tend to suggest what may amount to "over engineering" (as you put it), I suppose, because I don't have any personal experience with anything this large that has been built by a regular Joe (and I don't have alot confidence in my ability). I appreciate your comment about your friend who built the 500 gallon the way he did.

The more I look around on the web and talk to people, the more I have come to conclude that (as you have already stated), guys use this method frequently and it appears to be a time tested method. Building a sturdy box and using epoxy and perhaps fiberglass in the joints, should work for me just fine. It all goes back to that whole confidence issue, I'm sure.

I posted in MFK for suggestions and feedback like yours, and I appreciate it!

Jason

 

[loogielv]

and i hope i didn't make it seem like i was criticizing you for a) your build or b) posting your build ideas. It was more brought on for the replies you received there after. Again, I'm not slamming anyone. These people here are great. Just tend to over analyze and suggest things that won't work any better, will only add another layer of difficulty to your build, and will only add one more point of possible failure.

this thread just gave me an idea. watch for my thread in the diy forum...

 

[Rivulatus]

and i hope i didn't make it seem like i was criticizing you for a) your build or b) posting your build ideas. It was more brought on for the replies you received there after. Again, I'm not slamming anyone. These people here are great. Just tend to over analyze and suggest things that won't work any better, will only add another layer of difficulty to your build, and will only add one more point of possible failure.

this thread just gave me an idea. watch for my thread in the diy forum...

It's all good, loogielv.

I'll keep an eye out for your thread. J