Water Trapped Between 2 Panes of Glass

Not really glass, but acrylic (aka Plexiglas). But you get the idea.

The story is this: I designed my own aquarium to be made of acrylic sheets, 3/8" thick. For strange reasons that are pointless to this query (regarding additional stress to that side), I made one wall of the tank to be made of two sheets, side-by-side. So it’s actually 3/8"+3/8" = 3/4" thick on that side.

I ran the water test today, to see if there were any leaks. There is no water leaking outside tank, but I see clearly that there is some water that found a way to sneak between the two sheets of acrylic. :smack: So it is trapped between these two sheets on the side of the tank. It made some interesting little bubble patterns there as well.

Actually, it was kind of strange to watch the water get in there – by capillary action, it immediately rose above the waterline to fill all of the space between the two sheets, except where it cut itself off and made little bubbles here and there.

Question 1: Will this water, as I fear, grow algae or some strange substance, and so turn green and then brown as it all dies out, forever cursing me with an ugly brown stain on the side of my tank?

Question 2: Can you think of any way (short of ripping the whole thing apart) to get that water out? If it were a glass tank, I’d think of shoving the whole thing into the oven and baking it at a low temperature… but it’s plastic and it wouldn’t fit anyway.

I wouldn’t mind drilling one or two or four pinholes in the side of the tank to release the water (then plug them back up with silicone), but I doubt that would get all of it anyway. Simple gravity won’t pull the water out - water, with its adhesive>cohesive properties, will stick to everything other than itself (in general).

I think I’m stuck.

Hmm. Dunno about the algae - it’s certainly possible, I’d guess.

As for the other, you could drill a pinhole, and then somehow worm the end of a paper towel down into the water and let it suck it out. But then you’d also have to figure out how to prevent it from getting back in.

Even if you do get the water out, other stuff is likely to get between the sheets. I worked with a glazier once, and one thing he tried to avoid was putting two sheets of glass together as you did. Double pane windows have a gap between which is filled with an inert gas,
Take it apart and replace with a 3/4" thick peice.
Ok, what the hell are you keeping that needs so much thickness? Whale?

No, that’s three inches. We have stuff that thick in stock.

Or maybe just plain paper, since the pieces are tight against each other. Not a bad idea… but I can imagine poking down at the bottom, and having the (now wet) paper tear and get stuck in there as well. That would make a bad situation even worse.

Not a problem. If (hypothetically) we can evacuate all the water, I know just where the leak is that started the whole thing. A little dab of silicone, and it’d be sealed off again. Or alternatively, a little dab of silicone, and the water that’s in there will be sealed in forever.

(snicker) The thickness is supposed to be governed by the depth of the tank. Actually I’ve no idea what to put in it yet. I’ll likely start with feeder fish to get past the new tank syndrome. Then who knows. One step at a time.

Maybe this will explain better: Take a look at this picture. The top layer with the holes cut out is there to prevent the sides from bowing out. But, on that part of the tank, I planned to put a hanging waterfall-style filter. So I thought I’d be smart and just add one small section that is 2 layers thick, and then put the regular cap the rest of the way around. That was my thinking at the time, be it reasonable or not. The design looks cool, really…

Sigh. The more I think about it, the more I think it’s hopeless. Maybe I’ll just get a picture of underwater rocks or something to put over it.

Good grief… I imagine you could make a bridge out of that. Now THAT would be cool! (and a little scary)

Well, you can try to seal it. Nuttin’ to lose, eh? :slight_smile: The root problem of two layers is that when the temperature changes, the air between expands and contracts. That’s what can suck the bad stuff (condensation, dirt, dust, etc) in over time.
Man, that’s one BIG tank. I was thinking 10 gal and goldfish. :wink:

Yeah, the one in the picture is about 180 gallons. I’m not quite that crazy, but plenty envious. Mine’s just short of 30 gallons.

I also love this picture of a 8’ long tank that is also the headboard of a bed. Gives new meaning to the phrase “wet dream”.

The adhesion of the water to plexiglass is going to make it hard to get all the water out using just paper towels. You might be able to able to blow the liquid out with dry pressurized air. A small hole drilled through the outer piece near the top back side, could be used to attach, by glue or friction, something like a syringe body, or bit of 1/16" id plastic tubing. Attach a low pressure source of air, such as from a regulated cylinder, or a reversed vaccum cleaner stopped down to size with tubing, duct tape, and a little T fitting with a pinch clamp for pressure regulation. Still, it could take days to get the space completely dried out depending on how much airflow is practical.

OK, slight hijack, but im in the market for a 55-75 gal. How much did your 30 cost you to build? Was it difficult or could somone with very little experience with plastics handle it?

Could you take a hair dryer to the side of the tank for 20 minutes or so? Just start heating the plexiglass (not to the point of melting or discoloring of course) and watch the water evaporate out… that small a volume shouldn’t take long. Alternately you could try blowing warm air down into the fissure on one end, tape the top middle section closed, and have a space on the other end for the air to exit so it’s forced down and across. Either way should work.
Of course you’d have to plug the hole where water’s getting in beforehand. After that I’d suggest running some tape or a bit of silicone along the top “crevace” between the two panes so that dirt won’t get in and so water vapor won’t condense there (or soak back into the crack when you splash a bit of tank water on the rim).

Yes, algae will happily grow there; at least somewhat. I have a tank with a lid made from two sliding panes of glass like so:

          <--  _____________ -->          

The water from the sponge filter bubbles up and gets into the space between the two drop by drop, and grows a nice mat of algae for me.

If the tank is small enough to move and you can drain it for a day or two, I’d suggest simply sitting it in the sun for the afternoon and letting it get nice and warm & dry. Then seal your holes and cracks, and return it. If there are no fish there yet, it won’t hurt to drain & dry it out for a day.

The 3-inch thick in-stock bit was in reference to Star Trek 5 (I think) when Scotty was trying to build an aquarium in the ship for the two humpback whales ((but the thickness was 6", not 3 :D)).

It was a lot easier than I thought, and it looks great. I had the plastics shop do all the cuts (since they had to be exact) and also buff them smooth. They billed me $200, including both the cost of the original 4’x8’ sheet of 3/8" acrylic (I used less than half of that), a few curved cuts, and the cost of buffing the cuts smooth (Which I think makes it look a lot nicer). I expect that the cost would have been the same if I’d have gone with a tank twice that size, because it all starts with that 4’x8’ sheet, most of which I gave back as scrap.

In the end, I’m very glad I made it myself, because it was easy and because the result fits exactly on the shelf where I wanted to put it. I followed the directions here.

So far, this one certainly seems to be the least invasive, so I think I’ll start with that and see how it goes. Then start to look at using hyperdermic needles to get an air flow going… Wish me luck!:cool: