Are you going to glue the two acrylic pieces together? You can lightly clamp them together so they are properly alligned, and then use a small syringe with a 26 gauge needle or similar to squirt some cloroform into the space between the acrylic pieces. As long as you are careful in applying the cloroform and go around the perimeter, you can have a great and lasting bond between acrylic pieces that will also be completely clear. It's something I tried once when I found out that cloroform can be used as a glue for acrylics, plus I have access to a gallon of the stuff =)