Plumbing plastic pipe reference guide

Here are a few tips on how to plumb with plastic pipe and fittings using threaded joints and/or solvent welding.The following is recommended for piping systems normally encountered in the swimming pool and spa industry.

1. Threaded Joints
   1. Plastic to Plastic
      1. A dry male fitting should be made up hand-tight about two-thirds (2/3) of the way into any female threaded connection.
      2. Use only the following plastic-to-plastic thread sealants.Teflon tape, 100% pure Teflon paste or Permatex # 2. Use three (3) full turns of Teflon tape.
      3. Apply sealant to male thread only. Use liberal coats of either the 100 % pure Teflon or Permatex # 2. Use (3) full clockwise turns of Teflon tape.
      4. Screw the fittings together hand-tight. Then (1/2) to (1) more full turn using a strap wrench or small pipe wrench. You now have a good joint-stop.
   2. Plastic to Metal
      1. Be sure to clean or deburr any rough metal threads to prevent uneven covering of sealants or tearing of the tape
      2. The same sealants are recommended as above.
      3. Avoid the use of a male metal threaded end into a female plastic thread, whenever possible.
         1. If heated water of any degree is involved, the different expansion rates could cause leaks.
         2. Tapered metal male fittings over-tightened into plastic female threads can create stresses that, though not immediately apparent , can cause fractures later.
         3. Screw the fittings together hand-tight. Then, (1) more full turn using a strap wrench or a small pipe wrench. You now have a good joint-stop.

   Note: Most common plumbers oil-base pipe dope compounds should not be used with plastic pipe, valves, or fittings. Cracking or breaking of valves and fittings has been caused by the effects of some of these pipe dopes, failures occur shortly after use and over prolonged periods of time.

2. Solvent Welding
   1. Avoid using the so-called all-purpose cements or spray can types.
   2. Use a good solvent cleaner-primer on all slip pipe and fittings.
   3. Quickly, while surfaces are tacky , brush on a moderate coating of cement to the fitting socket and the pipe end.
   4. Within 5 to 10 seconds, insert pipe giving it a slight twist until it bottoms out.
   5. Hold joint for 5 to 10 seconds to prevent the pipe from pushing out of the socket.

Note: You can handle almost at once. Do not put any stress or twisting force on the joint for at least 20 minutes. Do not pressurize for at least 2 hours. A full 100 % joint strength takes 48 hours.