So you are saying 4'x4' viewing window, so are you planning 4' deep?
If you are doing 4' deep than you would be asking for failure if you go with 3/4" acrylic. 3/4" glass might be OK (still not safe IMHO) but definitely not acrylic.
Boat window acrylic is still just acrylic. As long as it is cell cast acrylic it is what you want. But if you are going 4' deep than I would say 1.25" is the MINIMUM and 1.5" would be what you should really go with for acrylic. If you think you can do 3/4" acrylic in a 4' deep tank than go for it. Just be sure to post your failure and how it fails so we can have a clear example to show the next person that thinks they can skimp on viewing window thickness. And hopefully you don't get hurt or hurt anyone else.
Just remember, we are all trying to help you and provide our advise and experience. The physics behind your tank design is not that complicated and the more I look at it the more I agree with myself on what you need for viewing window thickness.
Jointing the inside corner of that tank (if you don't want a brace there) would be easier with acrylic in my opinion. Acrylic, solvent welds together to create one piece. I have worked with acrylic quite a bit and it is pretty easy to use as long as you have the tools to work with it. A router table is basically a must.
Glass would probably be fine with a normal T type joint as long as you have the proper thickness of glass and good silicone. The proper thickness of glass would be 1". You could probably get away with 3/4" but I would highly recommend against it. Glass is far more dangerous that acrylic if it fails because it can fail completely all at once and with that amount of water and pressure being released all at once with large pieces of glass in the mix could kill someone.
If you are doing 4' deep than you would be asking for failure if you go with 3/4" acrylic. 3/4" glass might be OK (still not safe IMHO) but definitely not acrylic.
Boat window acrylic is still just acrylic. As long as it is cell cast acrylic it is what you want. But if you are going 4' deep than I would say 1.25" is the MINIMUM and 1.5" would be what you should really go with for acrylic. If you think you can do 3/4" acrylic in a 4' deep tank than go for it. Just be sure to post your failure and how it fails so we can have a clear example to show the next person that thinks they can skimp on viewing window thickness. And hopefully you don't get hurt or hurt anyone else.
Just remember, we are all trying to help you and provide our advise and experience. The physics behind your tank design is not that complicated and the more I look at it the more I agree with myself on what you need for viewing window thickness.
Jointing the inside corner of that tank (if you don't want a brace there) would be easier with acrylic in my opinion. Acrylic, solvent welds together to create one piece. I have worked with acrylic quite a bit and it is pretty easy to use as long as you have the tools to work with it. A router table is basically a must.
Glass would probably be fine with a normal T type joint as long as you have the proper thickness of glass and good silicone. The proper thickness of glass would be 1". You could probably get away with 3/4" but I would highly recommend against it. Glass is far more dangerous that acrylic if it fails because it can fail completely all at once and with that amount of water and pressure being released all at once with large pieces of glass in the mix could kill someone.
