Just the front Box, weirs and rear lid are Polycarbonate. The rear box is made of Translucent ABS. ABS and PVC can be bonded together. The 3 x 1.5" drains are slip fittings and can be welded with medium PVC glue, All Purpose Glue or ABS to PVC Transition Cement. We have tested them with all 3 and to be honest, regular medium PVC cement works great.
so like this primer: http://www.homedepot.com/p/Oatey-8-oz-PVC-Clear-Pipe-Primer-30751/202985691
and then hit it with this cement: http://www.homedepot.com/p/Oatey-8-oz-PVC-Medium-Gray-Cement-308843/203477293
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