I have some thicker 3D pieces that I am carving from .75 and 1 inch thick cellular PVC “lumber”. Just wondering if others are using this material? Its cheap, readily available as boards from HomeDepot etc. It makes a mess, a lot more than the HDPE or Delrin that I otherwise use. But other than that, are there any downsides?
I’ve been using that for a few parts. Machines really well, but the mess! 
It has a low melting point. So be careful!
However it is a nice alternative to HDPE.
I have used this PVC molding to make knobs and other simple parts.
i found this also i like it cuts clean works great for what i need