A. Lasco Manufacturing says: "It is wrong to add excess bulk to a threaded joint by wrapping male threads in Teflon� tape. It is wrong to make over-tightening easier by using TeflonÂ tape..." We have seen much similar PTFE thread sealing tape used satisfactorily but cannot (due to liability potential) recommend that you use PTFE thread sealing tape (pipe dope designed for PVC, such as we offer above, is acceptable).