Take advantage of a methylene chloride solution to bond two pieces of Lexan polycarbonate together. Methylene chloride is a solvent that softens Lexan enough that it can attach directly to another piece of Lexan. The solvent dissolves, and the two pieces of Lexan become fused together. The process is called plastics welding. Methylene chloride is the primary ingredient in a number of commercial plastics welding compounds available at most hardware stores.
Put on your respirator and rubber gloves. Open all windows in the room or relocate to an open-air location to prevent against the buildup of toxic fumes.
Lightly sand the locations where you want to glue the pieces of Lexan together. The locations should be smooth to the touch.
Apply the methylene chloride solution to the Lexan according to the instructions on the package. Most solvents designed for plastics welding come in containers with eye-droppers for purposes of application. The solvent is thin like water and takes some practice to use well, so consider experimenting on some scrap pieces first.
Clamp the two pieces together and wait 24 hours for the bond to achieve its maximum strength.