Caulking 2 1/4" sheets of glass together

[jworth]

I need to replace a back panel of glass and a 1/2" sheet costs 130 and two 1/4" cost me nothing. could i caulk the two pieces together to form my back panel. what i mean is pancaking them together to form 1/2" glass. the panel would be 72x20. could this work?

 

[KAWAMIKIE]

I did the bottom of a 75 years ago with two pieces of 1/4" and it never had a problem.
In your case though I don't know, that's quite a span. If you can get the glass for free then go for it. Leave it filled outside for a week or longer, and if it holds up it should be fine. The center brace/braces must be part of the frame or you will only be attached to the inside glass. You want both pieces of glass very clean and don't put silicone between them.

 

[LOPAKA]

I'd give it a shot. Paint the piece that will be closest to the front of the tank black and silicone the other piece to the back of it so when siliconed together it won't give the appearance that there are 2 pieces.

 

[jworth]

I'd give it a shot. Paint the piece that will be closest to the front of the tank black and silicone the other piece to the back of it so when siliconed together it won't give the appearance that there are 2 pieces.

this is what i am going to try. it is free so i suppose it couldnt hurt to try.

 

[Conner]

I guess the worst that happens is it fails, and you go buy a piece of 1/2" glass, right? How about finding a tank to salvage it from on craiglist?

 

[jworth]

I guess the worst that happens is it fails, and you go buy a piece of 1/2" glass, right? How about finding a tank to salvage it from on craiglist?

well i got this 125 for free because it busted and needed a new back panel. i can get the 1/4 for free so I want to make this project cost me nothing but time and footwork. I plan to keep it in the garage as it is, so even if it fails (which i dont think it will) I will not be heartbroken and it will have cost me nothing.

 

[earthstudent]

I would say you need to join the 2 pieces of glass for max strength.

I would clean the sides of the glass to be joined, very well. Then take silicone and run a HUGE bead down the center of one of the pieces. Not from end to end but about 10" in from the ends. So you have a 1"-1.5" diameter sausage of silicone running down the middle (long ways) of one piece of glass about 10" from any side. Try to make the silicone bead as even as possible as this will help avoid bubbles when applying the other piece.
Now get 2 or 3 other people to help you apply the other piece of glass. With a couple people on the next piece of glass, lower the 2nd piece onto the first. Evenly lower it so you smash the silicon out to the edges evenly. Have another person push down in the middle to help distribute the silicon evenly, tho the weight of the glass may be enough. Press the pieces together the best you can. Clean all the excess silicone from the edges.

You should end up with 2 pieces of glass with a thin layer of silicone in between, with no or very few bubbles of done well. Make sure the pieces are laying PERFECTLY FLAT. This should theoretically be more ridged than a single piece of 1/2" glass.