Use two types of Teflon on threaded joints
Connections that rely on threaded pipes and fittings are prone
to leaks if they're not sealed with either Teflon tape or Teflon
pipe joint compound. Careful plumbers use both on every
joint for extra security. They don't want to come back.
Start by wrapping the male threads with Teflon tape (Photo
1). With the end of the threaded pipe facing you as shown,
wrap the tape clockwise. Usually three layers is enough. Once
in a while, you'll run into a loose fitting that requires four or
five wraps. Stretch and tear the tape to complete the wrap.
Spread a thin layer of Teflon pipe joint compound over the
tape (Photo 2). If you're working with plastic pipe, choose
Teflon pipe joint compound that's compatible with it. Then
start the threads by hand before tightening the connection
with wrenches (Photo 3). Wipe away the excess.
Lubricate the ferrule on compression joints
Compression joints are most common on shutoff valves,
although you find them on other fittings as well. They have a
brass or plastic ring (ferrule) that's compressed into a recess
when you tighten the nut, forming a seal. Lubricating the
pipe and the ferrule with a bit of Teflon pipe joint compound
(Photo 1) helps the ferrule slide along the pipe and squeeze
tightly into the recessed fitting with less wrench pressure
(Photo 2). Tighten compression fittings firmly with two
wrenches to crimp the ferrule onto the pipe (Photo 3). Also
make sure the pipe or tube goes straight into the fitting.
Misalignment will cause a leak. If the fitting leaks after you
turn on the water, try tightening the nut an additional one-quarter
turn. This usually stops the leak.
Align slip joints precisely for a tight seal
Joints on chrome trap assemblies rely
on rubber slip joint washers for the
seal, which often leak. If you're
reassembling a chrome trap, buy new
slip joint washers and nuts. However,
new washers sometimes stick to the
pipe, causing them to twist or distort
as you push them tight with the slip
joint nut. To avoid this, lubricate the
drain tubing and slip joint with a little
pipe joint compound (Photo 1). The
compound helps the washer slide
smoothly and creates a tighter seal.
Start the slip joint nut by hand, and
twist it on until the threads are engaged
correctly. Hand-tighten all joints first
(Photo 2). Then adjust the trap parts
until they're aligned and pitched slightly
for drainage. This is key; a misaligned
joint will leak, even with new washers.
Finally, use a large slip joint pliers to
tighten the nuts an additional half turn.
Plastic trap parts use hard plastic
slip joint washers for a seal. Make sure
the flat part is against the nut with the
tapered side facing the fitting.
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Choose flexible supply tubes
The skinny copper or
chrome supply tubes used to
connect faucets and toilets (Photo
1) are tricky to cut, bend and align. But
you don't have to put up with them.
When you're replacing a faucet or toilet,
use flexible supply hoses with a braided
covering instead (Photo
2). They have rubber gaskets at each end
and don't require much force to seal.
They're available in many lengths and
are flexible enough to fit almost any
configuration. The only trick is buying a
connector with the correct size nuts on
the ends. Take your old tubing and the
nuts on each end along with you to the
store to be sure of an exact match.
Start the nuts carefully and hand-tighten.
Then tighten an additional half
turn (Photo 2). Avoid overtightening.
It's easy to tighten the nuts a little more
if the joint leaks.