300 Gallon Plywood Tank Leaking - Best way to seal? Pics!

brianhellno

Feeder Fish
MFK Member
Nov 30, 2008
264
4
0
USA
I built a 300 gallon plywood tank and used bolts to bolt the acrylic in place because I feared the acrylic would lose its seal. In an ironic twist the water leaks around the bolts and now I have several small leaks around various bolts. I put silicone around the bolt head of all the bolts on the inside to try to prevent this but I admittedly did a rushed job and probably didn't apply it as good as I should have. Now the question is: Should I take each bolt out one by one and apply silicone to the threads bolt them back in and then apply silicone to the bolt heads or should I go over all of the bolt heads again and this time do the job right?

It seems that only about six of the bolts are leaking and they are leaking very very slowly. Their may be more but once I checked it and saw a couple leaks I just started draining it. It takes about an hour for the leaks to appear after the tank has been filled completely. All opinions or advice are appreciated in advance.

IMG00099.jpg
IMG00100.jpg
IMG00101.jpg
 

cvermeulen

Jack Dempsey
MFK Member
Jun 4, 2007
1,876
3
36
Los Osos, CA
Holy crap dude, that thing should be in the ghetto DIY thread. Part of your problem could be the nuts only engaging your pane dividers by a sliver of metal. The other part could be that silicone is not great for sealing to acrylic, unless it's just forming a gasket (you're using it to seal around the bolts, and hold pressure that way.)

Taking the bolts out one by one and resealing MAY help, but probably not because new silicone doesn't stick well to old silicone. If you want to "do it right" take that whole front panel off and throw it in the garbage. Make a new one with a wide enough center pane divider, and reinstall your windows with NEW bolts, using a modern adhesive like DOW 732 or that 3M marine adhesive that actually sticks to acrylic and stainless steel, instead of regular pure silicone.

what kind of bolts are those?
 

nolapete

Jack Dempsey
MFK Member
Jun 1, 2007
2,726
9
38
New Orleans, LA
If you don't want to scrap the front acrylic pieces, you may be able to resolve the problem by installing a washer and snug gasket on each bolt. An alternative to that is to get a section of rubber pond liner and cut it to be a gasket then add washers to each bolt. That said, reading what other people have done first would have saved you from this headache.
 

brianhellno

Feeder Fish
MFK Member
Nov 30, 2008
264
4
0
USA
lol yeah I'll admit it's not exactly easy on the eyes. Kind of an abomination to plywood tanks visually. I did screw up the center support there and I was actually going to put a metal brace between the two bolts opposite of each other across the center piece of wood there to take care of the way its held in place. I probably should start over with the whole front piece. Do you think taking the bolts out one by one and resealing with 732 or 3M would do it? It only leaks around the bolts. They are stainless steel bolts.
 

basslover34

Jack Dempsey
MFK Member
Sep 3, 2007
4,852
9
38
Montreal
cvermeulen;2842467; said:
Holy crap dude, that thing should be in the ghetto DIY thread.

:ROFL: You took the words right out of my mouth... but I didn't respond :ROFL:

I have to admit that I think your center brace is the major problem as well... chances are though that if you could fix that center brace and then use some new bolts put silicone (yes I said silly cone) since your attaching those bolts through the plexi and the liner I would fill the hole of each bolt stick the bolt through lightly snug it get them all done, let it set up for a couple of hours then tighten it up abit more to (squish the gasket that you just made) then silicone over the bolt heads in the tank

Not sure if it will work but it seems to be worth a shot IMO
 

Issack

Feeder Fish
MFK Member
Mar 10, 2007
224
3
0
Big Island Hawaii
Wow man.... just wow.

I agree with what was said above.. take that whole front off and start over. use 2x4 studs on the face and make a big enough lip to glaze your acrylic to that it covers up the holes from the bolts.

This guy has a good test with silicone on acrylic.. he went with GE 1. Remember.. the water pressure will hold your panes in.. http://www.monsterfishkeepers.com/forums/showthread.php?t=119752&page=6

I would ditch the bolt idea all together.
 

cvermeulen

Jack Dempsey
MFK Member
Jun 4, 2007
1,876
3
36
Los Osos, CA
Actually, I'd like to re-comment here. I shouldn't have been an ass. There is no hiding it, that tank has some serious shortcomings in the aesthetics department. BUT, it held water, except for some leaking bolts. It's a step up from the inflatable ponds some of us use in a pinch. Bravo for being enthusiastic, and posting pictures anyway. I've done many things in the ghetto-fabulous fashion myself. Believe it or not, you posting this thing barely holding together, but full of water nonetheless has lent me a renewed confidence in the design for my 600gl, that I'm sure lots of people will tell me is under-designed. Thanks for that.

HOWEVER, I really do stand by the idea that you need to take that front panel off and re-cut it. There's really nothing else wrong with the tank (except maybe those cross braces - I wouldn't trust them, but they're easy to re-think.) A new sheet will only be around $20, the biggest PITA will be getting the silicone off your existing windows.
 

brianhellno

Feeder Fish
MFK Member
Nov 30, 2008
264
4
0
USA
Wow thanks cvermeulen. To be honest I kind of didn't want to post pictures because I know its not exactly the best looking (an understatement I know) but at the same time since it was my first build I decided to "test the water" and just learn about it and get some experience. Actually its so strong the tank doesn't bow at all when full of water. I made the cross braces about a quarter of an inch longer than the tank so that way I knew it was pressing out against them but even when all the way full of water I could just lift them off and set them back on again. Trust me I'm still going to use them but it seems like they will be there only for safety.

Also an update on the fix: I took each bolt out individually and applied 5200 to each one and tightened it back down. I then used 5200 around the head and washer of all the bolts. I have to wait a week but from what I understand if it leaks after this then all is lost. Also the silicone gasket remained in place around the windows so that should still be ok. Also making my tank even more ghetto than it already is I cut and put barstock between both the bolts across the center bracing so both bolts are held in place rock solid. I'll update in about a week with a test fill.
 

basslover34

Jack Dempsey
MFK Member
Sep 3, 2007
4,852
9
38
Montreal
Brian, Don't even worry about it's looks, We all have that one tank that isn't up to our visual tastes and we hide from everyone. Personally I think it wouldn't be hard to dress this bad boy up to look Outstanding but first things first you have to deal with the leak.

Are you sure that it wasn't leaking from the "gasket"? From the discription you gave it really sounds like you've nailed the fix but it's still a possibility
 
zoomed.com
hikariusa.com
aqaimports.com
Store