Aquarium Stand - question

[Roger Los]

I have told my wife (possibly when drunk) that I would build her an aquarium stand, and now it's coming back to haunt me.

It's a 40-gallon tank that will weigh somewhere around 300-400 lbs when full.

My initial sketches are of a stand 15" deep by 36" wide by 30" tall, with 3 x 3 uprights in the corners, 3/4 edge-banded plywood for the top, the same for a bottom shelf, and both of those supported with 1.5 x 3.5 stringers complete with diagonal braces in all corners to keep it all square. There will in addition be sides and a back, the sides consisting of 3/4 ply to support an adjustable shelf.

Now, my question. I'm in between shops at the moment and have a guided saw, router, etc. but will essentially be building this "on site." As such, mortise and tenon will be a pain in the kiester. Would either biscuit joinery or pocket screws provide enough strength for the corner post to stringer joints?

I hope some of the above is decipherable.

[Jack Wood]

You can count at least 10lbs to the gallon for water and then the gravel filters etc. could easily push your weight to 500lbs So building a stand is one of your problems but what comes to my mind is what is the stand and tank going to be sitting on? A slab floor will be good, but a floor over a crawl space might need to be bulked up some. As to the joinery I would pocket screw the stew out of it with water proof glue to boot on every connecting surface. I had a 55 gal tank crack on me and it was not a pretty sight at all, if the tank shifts at all once full, it could spell disaster. Good luck!

[Doug Shepard]

With all that weight I personally think I'd want some help from a wood joint as well as the pocket screws. Could you make a template jig and notch out a pocket for the stringers with the router (maybe 1 to 1.5" long) into the posts. Then another template to round over the stringer corners so they'd fit into the pocket ?? Then add screws as well ?? Just one thought.

[John Hemenway]

You might be over-building just a little.

I have two comerical build stands for 60G. tanks. Butt joints, particle board, 3/4 in. thick.

Since you have a router, dado for bottom shelf and top (depending on design), glue w/ waterproof glue like Titebond III. Back can be made up of 2 or three ply pieces. Use the 3/4" here. This will keep stand from racking. Leave gaps so you can get wires/hoses from bottom to the back of the tank.

You didn't mention face frame. If there is one you can make the top rail 'substantial' (4 "?) and use a ledge on the backside of it to support top.

Paint the interior gloss white, your wife will really appreciate it! The interior becomes a black hole without it. Another nice touch for the custom stand is the shelf covered in 'high pressure laminate' (aka, Formica). Seal the intersection of shelf and side so water can't get to the joint.

I don't think Whidbey Is. is earthquake prone, but bracing the stand to the wall gives lots of shear strength.

[Jim Young]

Here is one I made for my 75g tank. It's made of 3/4" cherry and the joinery is made with dowels. This was "very" early in my woodworking hobby so dowels were the first thing I could do. I would feel very comfortable doing it with biscuits now.



Here are some more pics and a short write up.
http://www.simoli.net/pages%20woodwo...s/fishtank.htm

[Ian Abraham]

I'm with John on this one, you dont need fancy joinery for a fish tank stand, you need lots of 4x2s and plywood

You do not want there to be any chance the top could sag, that will crack the tank.

I would go for 6 or 8 uprights, 4x2 or 3x3 etc. 4x2 pine is cheap and plenty strong enough as long as it's braced correctly. For bracing use the plywood sides and back, screwed and glued to the uprights. Now a 4x2 frame for the top and bottom, also screwed and glued to the ply. The top will just rest on top of the uprights, but is held in place by the ply sides. A few pocket screws and diagonal bracing wont hurt, but the ply will be the main bracing. So long as your ply & 4x2 box cant fold up you will be OK, and it wont because the ply acts as diagonal bracing.

Now do a fancy frame and doors for the front, and put some matching solid trim around the side panels to hide the screws, finish of choice is some sort of Poly as it's going to get splased with water at some stage.

Think, inside is built strong, like house construction, outside is finsihed with nice ply, trim and finish, like furniture.

P.S. my old 38" and 48" tanks never cracked, although the 48" stand we cheated and it had a steel frame inside. But that's just because Dad was a better welder than carpenter and it was his carpet it was sitting on

Cheers

Ian

[Bob Aquino]

For a 40 gallon tank, you dont need anything along the lines of 2x4 for construction, a plywood box made of 3/4" should be fine to support the weight. I recently built a stand for a 90 that is built using just plywood and it does fine for the weight. Here is a link to an online stand calculator: http://www.idahoreefs.org/Tank/BuildStand_2.asp

<img src='http://img.villagephotos.com/p/2005-11/1100992/newstand1.JPG' width=432 height=576 >

[Mac McAtee]

Wood in the compression mode will stand a tremendous amount of weight. You could build a stand out of 3/8" plywood like the one Bob has posted above, and it would handle all the weight you could put in a 40 gallon tank and more. Once you make the corners the thing is like a tank. (Sherman not glass.)

[Ian Abraham]

The guys are right, a stand just made from ply should be fine, most of the commercial ones are just MDF.
But I tend to err on the heavier side when building things. 2x4's are cheap, and wont be visible, so throw some in for good measure Use the 2x4s to create a solid join between your ply sides. No way they are going to fail then.

Over-engineered, maybe... going to fall down - not in this lifetime

Ian

[Jeffrey Makiel]

Bob...Nice reef tank. I take note of your Percula Clown and Yellow Tang!

Mac...I have a 150 gallon tank that is built into a wall. I used standard 2x4 framing material with plywood cross bracing. I think the cross bracing is very important, especially when cleaning the aquarium when water (and me) are moving and sloshing sideways.

It is very, very important that the top of your stand be level and supportive of the full area of the tank's footprint. If it is not level, undo stress is put on the tank's walls and will result in premature leakage a few years down the road. Poor support is something I have experience with! My first 150 gal tank did not have cross supports by the mfr along the top, and the silicone that glues the glass together finally gave out.

Also, if your decide to make a canopy top for it. Account for slight bowing of the glass when filled. Also, account for high humidity conditions.

cheers, Jeff

[Byron Trantham]

I had two 125 gal tanks whose stands were made from 3/4" pine! A pine top and bottom and pine verticals. It stood the pressure for over seven years (I sold them)! The back was pretty much open with only a couple verticals. The front had the same verticals but the spaces were filled in with doors. The inside seams were connected with 1x2 material screwed and glued.

[John Shuk]

The pocket screws will do great. Most stands sold retail are pretty much slapped together but they do just fine.

[Scott Fernald]

I built the stand for my 180 gallon tank out of 4 2x4 half-lapped box frames tied together with 4 6ft 2x4 stringers, again half-lapped together. Thats the static load bearing portion (as long as its a glass tank) around the perimeter. Plywood in the base and on the back to prevent any twisting. Been in service for 8 years and survived a move no problem.

I clad it with 1x4 pine (to mimic basement furniture) but that is just decorative...

This is way overbuilt for the load it takes (the empty tank is almost 400 lbs.) so using a frame that large for a 40 gal. is going to be overkill.

[Bill Grumbine]

Roger, I built an aquarium stand for one of SWMBO's coworkers. It sits under a 75 gallon saltwater tank. I used 3/4" ply and solid wood throughout, pocket screwed and glued. I do not know how much weight the tank is with all its water, rocks, sand, and fish, but I got on the stand to see if it would hold me (400 lbs) and it held me with no problem. It was also much stronger than the store bought stand they originally bought.

The test is, it has been in service for a year now, with no problems. It sits in a relatively new house, split level, on a plain old non extra support floor.

Bill

[Roger Los]

Wonderful information--thanks, gentlemen! The tank is acrylic, so it weighs about 45 lbs by itself, but the water and other goodies will push it past 400. Apparently with acrylic it's important to support the entire underside evenly, but I was planning on doing so in any case.

I think I will revise my design a bit, maybe I'll post it here if it's at all readable.