Figure 3-26.Diametric order of tightening flange bolts.
CUTTING.-When cutting plastic pipe, use
either a fine-toothed hacksaw, circular saw, band saw,
or reciprocating saw with carbide-tipped blades. Pipe
and tube cutters can be used when adapted with a
deeper cutting blade made for cutting plastic pipe. DO
NOT USE a tubing cutter. The cutting wheel will not
cut deep enough, and the outside diameter (OD) of the
pipe will become larger. Use a miter box or hold-down
rig to help cut the pipe square. Remove all burrs and
chips from both the inside diameter (ID) and outside
diameter (OD) of the pipe. The end of the pipe should
be beveled to approximately 1/16 inch to 3/32 inch at a
10-degree to 15-degree angle. This minimizes the
wiping of solvent from the ID of the fitting, as the pipe
is put into the socket. You can bevel the end of the pipe
with a coarse file or special beveling tool.
FITTINGS. Plastic flanges and flange fittings
(fig. 3-25) are available in a full range of sizes and may
be attached to the pipe. Soft rubber gaskets are
preferred with plastic flanges. When tightening flange
bolts, pull them down gradually to a uniform tightness
and in a diametrical manner, as shown in figure 3-26.
JOINING.There are four methods of joining
plastic pipe: solvent welding, fusion welding, fillet
welding, and threading. Before solvent welding PVC
and CPVC plastic pipe, clean the pipe and fittings, as
shown in view B, figure 3-27. Use a clean, dry cloth
and wipe away all loose dirt and moisture from inside
the fitting and from the outside of the plastic pipe.
Ensure the fittings and the pipe are of the same
temperature for at least an hour before welding; this
will assure they are thermally balanced. With a bristle
brush, apply a coating of primer to the outside of the
pipe. This removes surface gloss and etches the pipe.
Figure 3-27.Making cement solvent weld joints on plastic pipe.