How to Fix Cracks in Plexiglas

Attach the smallest drill bit you can find (preferably 1/16-inch or 1/8-inch) to an electric drill. Line up the bit with the very end of the crack and slowly drill a small hole through the Plexiglas. This interruption immediately stops the crack from getting any larger.

Use a can of condensed air or a damp rag to remove any dust from the drilling. For small cracks that are barely noticeable, this may be the only fix necessary, since the crack will not get any larger.

Inject methylene chloride adhesive into the crack to repair larger cracks. You can find this adhesive at plastic and boating supply stores, as well as some auto supply stores. The kit should come with a small injector; follow specific product instructions in case your chosen product requires any mixing.

Wipe off any excess adhesive from around the crack with a tissue or damp rag. Allow the adhesive to dry completely (per product instructions) before applying any pressure or vibration to the Plexiglas surface.