you guys have never been in the Ocean, on a rough day, in a fiberglass boat?
Check it out...10 Layers of laminate!!! over 1.5" of Plywood
Check it out...10 Layers of laminate!!! over 1.5" of Plywood
My 800 Gallon Plywood tank build
- Thread starter marinelife
- Start date
1.5" will be more than enough. I ran the numbers on pure joint strength when designing a 12' long x 4' deep tank, and most people's fears are way out of line with the actual strength requirements of the tank.
I dunno about the maintenance on your typical reef system. I know in a FW tank I'd definitely hesitate to make it so tall just from a maintenance point of view - wanna get something off the bottom? gotta go in.
I dunno about the maintenance on your typical reef system. I know in a FW tank I'd definitely hesitate to make it so tall just from a maintenance point of view - wanna get something off the bottom? gotta go in.
Oh and the DOW silicones are typically quite good at sticking to acrylic. I don't know about the compound you have chosen, but 832 and 732 both bond to acrylic. I would not recommend putting epoxy on the acrylic before the silicone for a host of reasons, the first of which would be serious lack of history on the design - all the other acrylic fronted plywood tanks I've seen use plain old silicone - since it's in compression, it doesn't need to stick, it just has to be there.
I have had a few people figure out the pressure and the rating for the wood and glue and they said I am way on the positive side for the PSI rating I would need.
P=density*g*h, = roughly 20kpa or somewhere around 3psi at the bottom seams (1.5 avg) 1.5psi*96in*70in = about 10,000lb of force on your front face. Sounds like a lot, but if you divide by the length of the 3 edges, it's only about 42 pounds per inch of seam, or 28psi across the 1.5" seam. This is basically nil in terms of material strength. The strength of silicone (which is relatively weak as an adhesive) ranges from 100 to 500psi. In other words, with 1.5" seams, you theoretically don't even need screws!
In other words - you're more than fine.
In other words - you're more than fine.
cvermeulen;2368887; said:
Not doubting you in any way, but your tank probably wasn't 6'6 either.
Again, I really hope I'm wrong here. I just wouldn't feel comfortable putting that much time and money in to an 800 gallon tank help together by screws and 1.5" plywood. I wouldn't be able to sleep at night.
Is there a support under the acrylic to keep the weight of it from slowly dropping over time? If the DOW silicone holds like some have said then it shouldn't be a problem. But I'm also a bit skeptical about the plywood holding. Not a failure of the plywood itself but the seams where its screwed together. 843G is just over 7,000 lbs of water. One other thing with the dimensions you gave the tank is actually 904 gallons and at the water lvl you gave of 70" thats 844 Gallons. 29x96x75=208800/231=903.896 Gallons and 29x96x70=194880/231=843.636 Gallons. Don't get me wrong here I want to see this full of water and up and running like everyone else here but if it were my tank I'd have some exterior bracing to keep the big box of water from exploding at the bottom.
