Let's talk DIY Plywood stands

kcinnick

Community Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 20, 2017
Messages
52
Reaction score
32
Review score
+0 /0 /-0
First of all, it is not a plywood stand if you start off framing the thing with 2X4's, that is a 2X4 stand with a plywood face!

I am contemplating building a plywood stand for a 72"X30"X25" tank. I know I can build a Square carcass fairly easily. I want to make the center brace on the front removable, I can do this with pocket screws fairly easily. I want a mostly solid back, I will have an opening to pass through plumbing and to have wires exit. Unlike all my previous builds where I used PVC and Flex PVC joins I think I want to go with the reinforced color tubing that goes on barbs this time around. I like that barbs are slip on/slip off if something needs to change.

Anyway, who has built a 100% plywood stand. I know the sides and back will be 100% strong enough being solid plywood, I am unsure of the front. How "tall" should the "header" and "footer" be? Do they need to be doubled up? I will do most of the construction with pocket holes, screws, and wood glue.
 

CMMorgan

Counting my blessings...
Review score
+0 /0 /-0
View Badges
Joined
Oct 12, 2020
Messages
3,784
Reaction score
14,483
Review score
+0 /0 /-0
Location
Punta Gorda
I hear you about a plywood stand .... but to me, the plywood is the exoskeleton. The skeleton would be lumber, aluminum or steel. I do not believe that plywood alone is engineered to withstand over 1500 pounds of weight. I would not sleep well with that in the house. I'm sure the engineers among us will jump in with more statistical data. Best of luck.
 
OP
K

kcinnick

Community Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 20, 2017
Messages
52
Reaction score
32
Review score
+0 /0 /-0
I hear you about a plywood stand .... but to me, the plywood is the exoskeleton. The skeleton would be lumber, aluminum or steel. I do not believe that plywood alone is engineered to withstand over 1500 pounds of weight. I would not sleep well with that in the house. I'm sure the engineers among us will jump in with more statistical data. Best of luck.
The front and sides of the stand I have now under a 300 gallon aquarium that is 32" tall are just plywood. The back is dimensional lumber, I believe to save money, not to be stronger. Also the back is open, I want a closed back, well mostly closed back. It has trim tacked on the front, but nothing that looks structural.
 
A Piece of the Ocean for Every Reef Tank
OP
K

kcinnick

Community Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 20, 2017
Messages
52
Reaction score
32
Review score
+0 /0 /-0
Why? Almost all commercially available stands are made of plywood. Plywood is a lot stronger than you think.
My man! Someone speaking my language. I just need some design parameters to go off of! I know what to do with the bottom, back and sides, just really need to know how much I need to beef up the front.
 

homer1475

Figuring out the hobby one coral at a time.
Review score
+0 /0 /-0
View Badges
Joined
Apr 24, 2018
Messages
7,213
Reaction score
10,575
Review score
+0 /0 /-0
Location
Way upstate NY
My 80G cube is an OSB plywood stand!

3/4" sides, and 5/8" top and bottom. The front is just a small doubled up "2x4" of OSB right under the front. The doors close on this panel.

Since the OSB has finally started to come apart, I'm having a cabinet maker I know build me a new one identical to this one, but made out of marine grade plywood.

Of course were talking a much longer tank then I have too.
 

dhnguyen

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Dec 23, 2010
Messages
467
Reaction score
676
Review score
+0 /0 /-0
Location
Kingston, Washington
My man! Someone speaking my language. I just need some design parameters to go off of! I know what to do with the bottom, back and sides, just really need to know how much I need to beef up the front.

Did you check these out?



 

mike550

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Oct 13, 2019
Messages
1,581
Reaction score
1,863
Review score
+0 /0 /-0
Location
Chicago
@kcinnick I’m totally behind you on this one. Plywood is super strong (think about gluelam beams) on edge. The stuff that @dhnguyen posted is super helpful. Keeping everything square will be important to load transfer. Maybe @RocketEngineer has some thoughts on this?

If you go forward with this please keep us posted!
 

ca1ore

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Oct 28, 2014
Messages
13,352
Reaction score
18,843
Review score
+0 /0 /-0
Location
Stamford, CT
Personally, I think plywood is superior to dimensional lumber for all but the biggest of tanks. I'd disagree somewhat with your generalization about what constitutes a plywood stand. Mine is actually a hybrid. Dimensional lumber for the verticals, laminated ply for the horizontals. 3 1/2 years and holding strong. The 'skin' is a combination of hardwood ply and hardwood boards. Helps on my system that the mechanicals are all in the basement.
IMG_0622.JPG


IMG_0512.JPG
IMG_0513.JPG
 
A Piece of the Ocean for Every Reef Tank

BZOFIQ

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 31, 2014
Messages
2,975
Reaction score
2,757
Review score
+0 /0 /-0
Location
NYC
I hear you about a plywood stand .... but to me, the plywood is the exoskeleton. The skeleton would be lumber, aluminum or steel. I do not believe that plywood alone is engineered to withstand over 1500 pounds of weight. I would not sleep well with that in the house. I'm sure the engineers among us will jump in with more statistical data. Best of luck.

Completely the opposite. You can easily park your car on top of a properly engineered plywood stand.
 

N.Sreefer

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Oct 16, 2020
Messages
1,171
Reaction score
1,724
Review score
+0 /0 /-0
Location
Dartmouth, N.S
"A 12-by-36-inch piece of 3/4-inch fir plywood can easily support 50 pounds. However, a 12-by-36-inch piece of 1/4-inch thick plywood will not support that much weight. It will only support about 5 pounds before bending."

"Assuming that the load is square and there is no wind, the average 8 feet 2x4 could handle around 1,000 pounds vertically."

Im confused how does plywood support more weight? You could wood glue a bunch of 2x4s together the same as plywood
 

BZOFIQ

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 31, 2014
Messages
2,975
Reaction score
2,757
Review score
+0 /0 /-0
Location
NYC
"A 12-by-36-inch piece of 3/4-inch fir plywood can easily support 50 pounds. However, a 12-by-36-inch piece of 1/4-inch thick plywood will not support that much weight. It will only support about 5 pounds before bending."

"Assuming that the load is square and there is no wind, the average 8 feet 2x4 could handle around 1,000 pounds vertically."

Im confused how does plywood support more weight? You could wood glue a bunch of 2x4s together the same as plywood

Nobody is building stands out of 1/4" plywood. Stands are built out of 5/8 or 3/4" plywood, in critical places, you simply double up.
 
Fritz

BZOFIQ

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 31, 2014
Messages
2,975
Reaction score
2,757
Review score
+0 /0 /-0
Location
NYC
Here's a very useful video I found as well


This video explains proper layout in great detail. Indestructible once sealed.

You can double up in the corners on larger builds, it will support tons of weight. The stand for my last 180 was build exactly like that with removable support in the middle/front.
 
Maxout
Your Reef
Top