Clear plastic is a useful and sturdy alternative to glass, more difficult to break and more likely to break into fewer pieces when it does. Nonetheless, when clear plastic breaks, the right glue and repair techniques are required to ensure that the fixed piece is as sturdy, attractive and waterproof as possible. Make the new joint stronger than ever without sacrificing flexibility or interfering with transparency.
Clean the pieces of plastic using water. Rinse with glass cleaner, vinegar or rubbing alcohol to remove all streaks and water stains. Buff dry with a soft, lint-free cloth or paper towel.
Join the plastic together at the broken seams. If joining flat panes of plastic, lay them on a clean, dry surface where their weight will hold them together while you work. If working with tall or oddly-shaped pieces of plastic, join them together with a piece of masking tape stretched from one side to the other (you will repair all but the taped portion, then remove the tape and repair this spot).
Mix the epoxy in the disposable container. Combine equal parts of the two liquids and stir with a craft stick until the solution starts to have a cloudy appearance; don't stop too soon, or it won't have a good hold. Mix only half as much epoxy as you'll need for the whole repair project, since you'll let the first half set before applying the glue to the other side.
Apply the epoxy to one side of the plastic. Smear a small amount of liquid over the seam between the two broken pieces. Smooth it out with the craft stick.
Use a clean craft stick to smear away excess epoxy, pressing the flat edge against the plastic, perpendicular to the seam, and smoothing it down. Let the stick act like a window wiper, moving excess resin to the edge of the plastic for removal.