| It surprises me that excessive glue is used on the pipes. These are pvc pipes and I assume the glue used is a mix of tetrahydrofuran, cyclohexanone and pvc resin (ie the same ingredients used in model making plastic glue). This glue basically melts pvc and it is this melting reaction that causes the pipes to seal with each other. If too much glue is applied, it melts away the wall of the pipe, weakening it. I had this problem with my reticulation, where a pipe burst just before the joint because the excess glue had weakened the pipe wall.
In terms of roughing up the pipe, it doesn't need to be too rough, just enough to rub off the chemicals and ensure that the actual surface that is too be glued does not have any bumps, lumps, bits of debris etc. I've found that if the joints are properly glued, they are just as strong, if not stronger than the rest of the pipe. The weaknesses are usually near the joint, where excess glue may have pooled. |