Advice for Making Watertight Clear Cylinder

I want to create a relatively large (\~20'' diameter, \~10'' tall) cylinder that is transparent (for use in a laser system) and watertight (to serve as a tank). The base does not need to be transparent. These are uncommon dimensions and difficult to find a vendor that sells anything close to these dimensions. Some vendors like UVacrylic (https://uvacrylic.com/plexiglass/acrylic-tube) do offer open-ended tubes that I can cut to the desired height and attach to a custom base, but these are 1m long and expensive, so there will be a lot of waste. I'm wondering if anyone has advice or suggestions on how I can custom fabricate it? I have access to a machine shop, including a CNC machine. I'm also open to using glass, and outsourcing certain tasks. I have a budget of $300 but would prefer to get this done as cheaply as possible. One idea is to take acrylic sheets and bake it in the oven. Then bend it to the shape of a cylinder and use waterproof epoxy to seal it. Then finally, epoxy it to a base. However, I am concerned about the watertight-ness as well as the structural integrity due to the water pressure. Any help is appreciated, thanks!