Plastic pipe--it's easy to work with. It's much less expensive then metal pipe. My water pipes are plastic, my air lines are plastic (I think), my electrical piping is plastic. Yet, all I hear is that I'm not supposed to use plastic pipe for dust collection. Why?
Plastic pipe systems are not designed for dust collection use. A necessary diversity of fittings to meet design requirement does not exist. Also, plastic pipe elbows have a very short radius and plastic tee fittings are improper for dust removal. It is these types of problems that lead to an inefficient dust collection system.
My suggestion would be to convert over to a metal piping system. With a metal dust collection piping system you do not have the concern of static electricity developing. Elbows and other various fittings are properly designed for conveying dust. The diversity of fittings and accessories will enable you to meet design requirements. Inevitably, you will get the best performance from your dust collector.
Curt Corum, forum technical advisor