Large Plywood Tank

[blindhog1]

ldrhawke
I belive that useing epoxy over the fiberglass was your problem. The two materials are not compatible with each other. Fiberglass resin is a polyester resin and not an epoxy, and epoxy will not adhere to the polyester resin like it should. Wooden boat builders use epoxy resin to glue and seal the wood and paint it with an epoxy paint. Silicone will adhere to the epoxy pretty good if you sand the epoxy with 220 grit sandpaper first.

THE HOG

 

[salty joe]

Mastino Mike,

EPDM liner sounds good to me. Can you go into a little detail concerning viewing panel attachment? If I got it right, you use Weld-on 40 or something like it to glue acrylic inside opening of plywood box. Then you use silicone between acrylic & EPDM. If this is it, how do you hold EPDM flat while silicone cures? Doesn't water pressure force the EPDM against the corners of the acrylic panel, causing tear points?

Joe

 

[Mastino Mike]

Position the liner loosely in the corners so when filled the rubber doesnt stretch. The goal is to have no tension on the attachment. I just used a thin bead of silicone to hold the acrylic in place in the seams before installing the liner(the corners or tear points of the glass or acrylic that you mentioned) The liner is tough and it would take more than that to tear or cut the liner. The acrylic is not that sharp on the edges and I doubt it would tear the liner at all but I used silicone on it any how. I used weld-on first to glue the liner smoothly after sanding. You cant have any wrinkles in the attachment. Then I used a thick layer of silicone over the attachment. I then used weld on again in the seams of the silicone and the liner and the silicone and the acrylic dont know if that helped but I did it anyhow.

 

[Mastino Mike]

Salty joe,
Just fill any gaps or sharp points with silicone or foam. I have at least 3.5 inch frame on top and 4 inches on the sides of viewing frame. You also want the glass or acrylic to sit flush as possible my acrylic sits very tight in the front viewing panel without much gap between the sides.

 

[Mastino Mike]

Last,
Glass is very easy to install. Silicone would be all you would need. I would follow the same procedure except use just silicone. The goal is to form a water tight seal thats it. The attachment shouldnt have any tension at all when filled if it does then it was installed wrong and you may have some leaking problems or maybe not?

 

[salty joe]

Mastino Mike, Thanks for reply. Please excuse me if I seem extra dense, but I wanna be sure I've got this seal understood before buying materials.

Extra heavy duty plywood box, say 80"x40" front panel dimension, with a 72"x32" cutout.

Acrylic or glass viewing panel, 76"x36" centered on cutout and inside box, glued into place.

Inside front panel built up with plywood to be flush with viewing panel, so that viewing panel sets in a "pocket".

Cut a 72"x32" hole in the EPDM and silicone EPDM to inside of viewing panel.

Is this pretty much what you did?

Thanks,
Joe

 

[Mastino Mike]

Yes thats it! The pond liner being the inner most layer. Here is another tip about making the attachment. Glue liner in straight lines. Work your way down top right corner to bottom right corner and then right to left and so on. This way you will avoid wrinkles in the attachment.

 

[Mastino Mike]

Glue liner in small sections at a time.

 

[Mastino Mike]

I used a 4x4 frame so I would have something to tack down the liner to and add extra strength to the tank. My tank has no bow with no cross braces. Im going to add one because it might bow over time.

 

[SPC]

I used a 4x4 frame so I would have something to tack down the liner to and add extra strength to the tank. My tank has no bow with no cross braces. Im going to add one because it might bow over time.

Looks like those 4x's are pressure treated Mike, did you seal them in some way?

 

[Mastino Mike]

The liner overlaps them. I did not seal them, do you think I need to? They are not in any contact with water?
SPC

 

[Mastino Mike]

I did some research on pressure treated wood. As long as you dont have any direct contact with water or secondary contact from hands to water. It is fine. Outdoor ponds use pressure treated wood all the time. Thanx SPC it didnt even cross my mind during construction.

 

[SPC]

I wouldn't worry about it either in your situation, Mike. I know that some is used on outdoor ponds, but of course these are alot less sensative animals and to be honest, we really don't know for sure if it might be affecting some of the aquatic life in them.

The way I look at it, the EPA will no longer allow stores that sell lumber to cut pressure treated wood due to health concerns. This being the case, I don't think I'd want this wood to come in contact with my reef in any way.
Steve

 

[Shoestring Reefer]

Sweet! I'll keep that in mind when I need some more luxury neckties!