Plexi lined plywood tank?

[areze]

I think some epoxy would still be nescessary; for the bracing on top, and I think Id pretty much give 1 coat to the outside of the tank just for peice of mind to be sure the humidity doesnt hurt it long term. and so I can wipe the surface down from salt and stuff.

but the plexi should still cut down on many gallons of 100$ a gallon epoxy.

and most of all, its more durable.

 

[willjeff]

The idea epicentyr had with the cove molding would also work if you used it in the oppostie way for an overflow. You are right areze epoxy should be used over the whole thing, just to be safe.

 

[nonot8946]

it would probably work if:
1) the wood didn't warp
2) it was cheaper than fiberglass

I bet cheap glass could be had, it's not like you need to have high quality except for the front, plus it's easier to put together.

 

[lfjewett]

This thread really interests me. I've been looking at plans for a large ( near 300G ) tank in my new home. I want three side viewable and the ability to use acrylic bonds and plywood strength seems a little "too good to be true".

So to the experts out there using slim 3/16 ths material for the bottom it be possible to seem a 3/4" front viewing panel in place?

Would adding a 1/2 inch or 3/4 inch acrylic square stock to all the seems give adequate surface area to create good seals?

If the square stock were to be used at all the seams how would one go about sealing them? I've seen threads on bonding 2 surfaces together but 3 surface at once where gravity can't help on one of the seams? Weld-on #40 or Weld-on #4?

 

[slevesque]

Hi, funny I had the same idea last week.

At my workplace we are providing storage for different company and one of them made a big cleanup in their stuff, trowing out acrylic. I ran to recuperate a 5'x5', 1/4 inch piece. I also got 3 pieces 5'x1' and few 2x2 pieces. So many possibilities.

I was considering using only silicone to seal the edges. After all, the plywood is doing all the streight task. Since i dont have experience with silicone + acrylic I'll read a bit more around.

The idea of using an acrylic square stock is very interesting .

One last thing. There is another solution for a 'topview' only tank: using an EPDM pond lining sheet, if you don't mind the black color of it.

 

[areze]

silicone doesnt really bond, so it is possible that it could shift or just kind of come lose and leak in the corners.

all things considered weldon16 is maybe 10-15$ so theres really no good reason not to use it.

 

[slevesque]

the only Acrylic glue I can find localy is the weldon 2705 or the one they have at Home Depot, called oat, or something like this.

I agree, it would be better to glue and then add silicone for leaks.

 

[Bill Wann]

Ive done this befor , acrylic dosnt work well , the joints flex too much when it filled with water and crack . 16 wont hold . Use pvc sheet , its cheaper and can be welded or siliconed in . Ive made afew sumps with plywood and welded pvc sheet , it works great .

Bill

 

[slevesque]

Oatey pvc cement, this is the brand I can find at HD.

 

[areze]

thats totally different, HD doesnt sell the acrylic weldon; gotta go online for it. or whoevers supplying your acrylic might have something.

bill wann- thats why Im thinking it needs to be epoxied into place so the walls are fully supported and hold no weight. there is no other way to really make the acrylic be fully supported at all point except to bond it with something liquid.

 

[slevesque]

PVC sheet, never heard before. Is it sold at HD or alike?

 

[TANGBOY5000]

Since we're on the subject I think I may have found a solution to something that has been bothering me. The plywood tanks are all awesome, but the amount of work involved is tremendous. I've also seen that alot of the time even with careful planning and work there is a leak. I got my usual catalog from US plastics yesterday. They have polyethylene tanks for very reasonable cost. I think the 500 gallon was about $1200. That tank is 6'L x 3'W x 4'H. They recommend reinforcing it with plywood and 2x4s if you're going to fill it up with liquid. So that tank is waterproof, food safe, and corrosion proof. Since it's made of plastic it is easily drillable for and drains you want to put in. They also say they can make them to any dimensions you need. Now for my question, does anyone know what will bond glass to polyethylene?

 

[areze]

nothing... but the water pressure should maintain a seal with some silicone. if you applied pressure the other way though... it wouldnt be much of a bond.

I dont know if those tanks would hold their strength if you cut a side out though.

 

[willjeff]

I am interested in the pvc sheet, the flexing and cracking was the thing that worried me. So areze your idea is to epoxy each piece of acrylic to its designated wall, then epoxy in a corner piece of acrylic to connect the walls, right?
Tangboy I am looking to get away from the $1200 price tag, other wise it would be a great option.

 

[wildcats]

Would the acrylic have to be thicker than 1/4" if you limit the opening to say 12-16" and then its braced all around with wood to prevent flexing? Limits viewing but cheaper

 

[areze]

that is my idea, lay in the epoxy then drop the sheet in. probably do bottom first, then front and back, and finally the sides. each time rotating the tank so the side your working on is on the ground; then the epoxy can just set there, and lay the acrylic sheet into place. should be fully supported then. all the weight transfered straight through to the wood.

could be difficult to do on a MUCH larger tank. my future tank will be 12x4x4' which IMO is still workable and able to be stood on its ends as well as moved with enough helpers.

as for the corners, the sheets of acrylic should be all jointed nicely, if the cuts are done accuratly weldon 4 shouldnt be out of the question, with some weldon 16 for additional corner strength. but yeah, a corner peice of acrylic for the seams could be a very viable option for additional strength, probably a better choice if you were to try thinner acrylic walls.

if you wanted an acrylic viewing panel you could make the front panel a full size sheet of nescessary thickness and bond it right into the tank and be 100% water tight, wouldnt have to worry about siliconing it in.

I want a glass viewing panel for scratch resistance though. willing to sacrifice that bit of sturdiness for it.

 

[areze]

wild cats, youd probably be ok, it would depend where the 12-16" viewing window was though, Id say as long as the bottom of it wasnt anymore than maybe 20-24" deep you could get away with it.

 

[willjeff]

Is there a specific epoxy paint that one would use, there are alot of them?

 

[cb350z]

plywood replacement

plywood replacement

i like the idea of a cheap homemade tank. instead of plywood i was thinking about using the plastic that is used for boards in ice rinks. this white plastic comes in sheets that are anywhere from 4'x8' to 6'x14.' it also varies in thickness from 1/4inch up to 3/4 inch. it may be a bit more expensive than plywood, but u eliminate the 20 coats of epoxy paint.

 

[areze]

its probably quite expensive. probably not too much less than acrylic.

wasnt a specific epoxy I have in mind, Im atleast a year or 2 off from doing it because of the multitude of other expensive equipment a tank in the 1200g range would require. when I get closer Ill investigate good epoxies, and probably go with a smoked 1/4" acrylic.