10 Mistakes When Working with PVC Pipes and Fittings

The following insights supplement the core advice about common mistakes when working with PVC pipes and fittings, offering practical solutions and highlighting the importance of precision and correct material usage in plumbing projects.

Proper Use of Primer and Cement: Use the correct size applicator for primer and glue based on pipe size. Applying glue in opposite directions on the pipe and fitting improves bonding. Some users recommend priming both surfaces for stronger joints.
Material Compatibility: Never thread plastic female fittings onto metal male threads, as differing expansion rates can crack the plastic. Instead, use plastic male threads with metal female threads.
Cutting and Deburring: Properly cutting and deburring pipes is crucial to avoid future clogs. Some users prefer chamfering (angling) the pipe edges, especially when twisting isn't possible.
Dry Fitting: Be cautious when dry fitting, as pushing the fittings too far can make them difficult to separate.
UV Exposure: Sand old PVC pipes that have been exposed to sunlight before bonding to new pipes, as the surface glaze can interfere with the glue bond.
Teflon Tape and Pipe Dope: Some users suggest using pipe dope instead of Teflon tape for plastic fittings, but avoiding plastic female threads on metal is crucial.
Twisting Joints: Twisting the pipe a quarter turn when gluing ensures better distribution of the cement, but some recommend avoiding this in European plumbing due to different practices.
Plumbing Regulations: Always check local plumbing codes, as some areas require the use of specific materials (e.g., ABS for venting or purple primer for inspection).
Using the Right Type of Fittings for Hot Water: When connecting PVC or CPVC to copper for hot water lines, it's important to use female copper fittings with male PVC/CPVC fittings to minimize the risk of cracking due to different expansion rates.
Handling Purple Primer: Be cautious with purple primer in visible areas. It's primarily used for inspections, and clear primer may be preferable for final touches to avoid staining floors or visible surfaces.