Best way to assemble a plywood tank?

S

slevesque

New member
Hi, I have read many plywood tank threads and sites and I realised people have assembled their plywood panels in different ways.

1-Some put the vertical panels against (around, outside) the bottom panel and some put them on top of the bottom panel.

2-Some put the side panels inside of the front and back panels and some put the side panels outside.

All tanks seems to hold good.

I'm not a carpenter enough to know it but there must be a "best way" of assembling the panels.

What would be your advice on both above cases?

Thanks, can't wait to start building my tank.
 
Wow! Very nice tank.

I wont be using epoxy. I will lined the plywood with 1/4 acrylic I already have, seaming the joint with either weldon16 or even just silicone for waterproffing. The plywood must be strong to hold everything. That's why I ask :). Glass in the front.
 
Hmmm.

I don't know about the whole acrylic thing. Make sure you research as much as you can. I can say that epoxy works great and in a 450 tank with 4x as much as needed it was only a few hundred bucks.
 
ok, forget about the weldon since I dont want the acrylic to hold the stress. I was thinking about making a wide joint of silicone (2-3mm maybe) to allow the acrylic panels to move out a bit towards the plywood if needed. The tank will be small compare to yours at 96x18x12. I would say 10 or 11" water depth so there should not be too much pressure on the plywood.

One question about epoxy: can you scrape coraline from an epoxy wall or it will damage it?
 
NO! Silicone barely sticks to acrylic. It does, but not in a structural way. I don't want you to have a disaster waiting to happen.

I would advise you to consider epoxy. There is no need to scrape coraline but if you really wanted to, I think a plastic credit card-like scraper would be fine. The stuff is very tough.
 
This is exactly what I want: no structural force to be undertaken by the acrylic or the silicone. Look at it as a semi-rigid pond linner or a thick piece of epoxy with the seams being sealed with silicone. Does it make sense the way I try to explain it?

I do need to scrape coraline. I dont like to see a wall covered by coraline. No offense to anyone, just my preference :).

I'm still considering epoxy but it has some drawbacks: I live in an appartment and painting 4-5 coats spreaded over a week might be inapropriate; 100$. Maybe if I can find a cheaper brand localy (Montreal).
 
The problem here is that the silicone will not seal your seams because it won't adhere to the acrylic. This compounded with the fact that you will not be using epoxy is a recipe for disaster. I would strongly suggest using epoxy to seal it and glass for your viewing panels. If you are worried about the fumes (which you should be) why not seal the whole tank outdoors? You can then transport it into the apartment and then silicone the glass panels in place. Without the glass the tank will not be too heavy. Two guys should be able to transport it.
 
I see, I didn't know the bond quality was that bad. Let me illustrate what I had in mind:

Brown=wood, white=silicone, blue=acrylic. Top view of a corner, side + back panels.

113720corner2.jpg


The silicone doesn't have to be that tick, just for quick illustration.

The acrylic panels doesn't touch each other. The idea is to use the gasket property of the silicone, same property we use to stick the front acrylic panel. Water pressure holds it in place even if the silicone does not bond to well. So, even the seam A or B leaks, the seam C will operate as a gasket and hold the leak.

It looks waterproof to me. What do you think?
 
It appears from the sketch that you want to cover all of the wood with silicone. You would have to since the water would eventually get behind the acrylic. I don't think you would be able to easily seal all of the wood with silicone and if you could it would take many many tubes of it.
One of the main goals for you is to avoid flling your apartment with potent fumes, correct? Since the tank is not very tall or wide (not extremely cumbersome to work with) have you considered making it completely out of acrylic? On the DIY forum there is a long thread giving advice on building acrylic tanks. It is extremely informative and you can ask questions if you have any, most have been covered. If your 1/4" acrylic is not thick enough (which I don't know if it is or isn't) perhaps you can frame it in wood for support.
I had a lot of decisions to make when deciding how to build my plywood tank. I chose the materials based on what has worked for the majority of others who have plywood tanks. I did not go the easy route even though I was tempted to. So the best advice I can give is to use a tried and true method: plywood, fiberglass and epoxy with glass panel, acrylic bonded with appropriate solvent, glass and silicone.
Best of luck. Please keep us posted if you go ahead with the project.
 
Hi Amanda, the sketch might be misleading because of the top view. Not all the wood would be covered by silicone, just the corners and the area around the edges of the panels, same as with a front panel. That should not take too many tubes.

My main goal is to find the cheapest (still safe) alternative DIY solution to a custom built all glass tank 12mm for 1000$ (incl taxes and deliv , quoted by Miracles Aquarium). Some constraints are my appartment (fumes), second floor, wood floor (weight).

I got the acrylic for free so I tried to find a solution based on it. With the help of Acrylics (the thread you are talking about) we tried to figure out if it was cell cast or extruded(weak bond). With no clear conclusion I decided to not try to glue an all acrylic tank with it. I also realised I would prefer to have a glass front panel for it's better scratch "resistence"

This is how I came to the above sketch. I used the proven method of gasketing a front acrylic panel to a plywood tank using silicone and applied this method to all the 5 panels. This way I can use a glass front. I agree it is unusual and innovative. Of course if I had to pay for the acrylic it would be more expensive then epoxy so pointless for me.

I'm still open to epoxy if I can find locally a safe brand for 50$ or so. I will check my local HD and alike next saturday. Being in Montreal I don't have access the same products you may have. I would get the sweetwater from A. E. at 57$ but int'l shipping, haz-mat charges, brokerage, will tripple the price. I know I can find the West System locally, have to look at it as well.

You might say that money is not everything and better be safe than sorry. I totally agree but using a 100$+ epoxy and fiberglass solution instead of the free acrylic comes just about 75$ shy of a DIY all glass 10mm tank with crossbraces (used by my lfs with the almost same dim as my projet). A small step I would probably take since I prefer glass. I'm still scared of building a glass tank though :).
 
If you were going to do it that way, you'd be better off using glass in place of the acrylic. At least then the silicone would bond well and your front pane would just extend to the edges. Essentially building a thin walled tank within a tank.

Of course if you did it that way the plywood would only serve to add structural integrity to the thin panes of glass. At that point you might as well suck it up and just spend the extra dough to build it out of thicker glass or acrylic.

I had considered building a plywood tank exactly the same way you want to do it, but after ghosting on RC for a while it became apparent that the design was flawed. If you want to keep it on the cheap, you will have to make sacrifices. In your case the corraline coating the epoxy may be the trade off for a plywood tank.
 
ok, ok I get it :) .

In another thread I already discussed about making a wooden framed glass tank. I found out the money saved by using thinner glass was going back on the project on the wood, glue, extra silicone, screws, paint or dye for the wood. I then abandonned the idea.

I know some companies does it by using PVC sheets which can be easily melted (with a solvent) and it becomes 1 piece. The wood support the thin pvc. Buying pvc sheets probably cost as much as buying epoxy though.

Sacrifices, yes, but it as to be much cheaper than the reference solution it tries to replace. I will see next week-end what epoxy I can get. Otherwise there is still 2 other solutions: DIY glass thank or buying another 4' tank and joining it to my existing 4' with an aquabridge to make a simili-8' tank :).

thanks for the reply
 
Speaking of PVC, you could also build an opaque PVC sheet tank with a clear PVC or acrylic front. Though, I'm not sure about the clarity of transparent PVC or how well the PVC to Acrylic glues bond???

I'm considering adding a large pond tank to my existing system to add volume, temperature stability, and a place to keep non reef friendly specamins.

I'll keep an eye on this thread.
 
My local glass shop made a mistake when giving me price the first time. They added the cost of clear polishing instead of the normal sanded edges. Sanded edges are correct, right? It brings the cost down by about 100$ after taxes! So now I can get the glass tank for the same price as the plywood-epoxy tank.
 
You landlord and anyone the lives below you will greatly appreciate your new plan over the previous plan. Somethings can be done on the cheap, this was not one of them. A plywood tank allows for great flexibility in size and shape, but doesn't allow any short sighted ideas or cutting corners or catastrophic failure is going to come.

Not meant as a flame towards you, more for future readers of this and might think they can pick up where you left off.

Good luck with your new glass tank.

Bill
 
No, I'm not going higher. I like my 10" water height :). I'm still curious to see if a yellow tang would like it though.

Speaking of landlord, last week I asked the owner about the condition of the floor and she said 800 pounds should not be a problem at all. But when I mentionned plexiglass she hesitated, looked at me and said "are you sure it's strong enoug?" :).
 
No one here can tell you what to do or what is best for your system. Our systems are as different as we all are. All anyone can tell you is what has worked for them, what they like, and why.
For me a 29" tank was the right choice. It has some drawbacks, like being harder to light, but for me it was the right choice because most of the fish that I like are seen in nature to be swimming above and around the reef. So I tried to provide as much swimming room above the reef as I could while still providing a multitude of variously sized openings for them to hide and sleep in. I'm far from being a "tang police" type, but I don't think a tang would be my first choice for the described dimentions for the above stated reasons. Not to say that my tiny 6' box is much better for the three tangs I have.
I am far more interested in fish than I used to be. I plan to make my next tank large enough to satisfy most of the "tang police." Hopefully my budget and wife to be will allow that to happen. :)
 
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