Q. I would like to comment on the ongoing pipe glue discussion from your November 2011 column. Users concerned about caustic service could look for what one manufacturer calls “industrial PVC cement” which is made without the fumed silica thickener. For small jobs, I have found that some cements available at home improvement stores do not list colloidal or fumed silica, so consumer protection being what it is, I think it’s a fair bet that those products don’t contain any silica. D.L.
A. My only caution regarding purchasing PVC and/or CPVC glues that do not specifically state they are for caustic/hypochlorite use and do not list silica is to test them on several joints to make sure they do not leak before using them throughout the piping system.