Begin laying the pipe at the tank with the bell end uphill. Joints in
clay-tile pipe are commonly made with portland cement mortar or grout.
Where root-proof joints are essential, sulfur-sand compounds may be
used or copper rings provided and used with cement-mortar joints.
Asphalt-mastic compounds, however, are more satisfactory. For cast-iron
soil pipe, lead is the standard joint material.
After the hub is pushed into the bell, oakum (or old hemp rope) is
packed with a calking iron or a piece of wood (fig. 3, _A_.) solidly
and evenly in the joint to a depth of about half an inch to center the
hub end in the bell and to keep the joint filler from getting inside
the pipe. Oil, grease, or dirt on the joint surfaces should be removed,
as it will prevent joint material from sticking. Figure 3 shows the
different jointing methods.
[Illustration: Figure 2.--Establishing grade for sewer. _A_,
2- by 4-inch stakes are set each side of the trench at convenient
distances _a_, _b_, _c_, and _d_. Then a board is nailed horizontally
on the stakes at _d_ at a convenient height above the bottom of the
trench, that is, the bottom of the sewer leaving the house. A board is
nailed likewise to the stakes at a the same height above the inlet to
the tank that _d_ is above the bottom of the trench. Similarly, boards
are set at _b_ and _c_ by sighting from _a_ to _d_ so the tops of the
intermediate boards will be in line. _B_, The exact grade of the sewer
is obtained by measuring from the grade cord with the 1- by 1-inch
stick, shown in detail. The length of the stick must equal the height
of the board above sewer at _d_.]
Bituminous, sulfur-sand, lead, and other commercial joint compounds are
poured while hot into the joint from a ladle (fig. 3, _F_), and when
the work is well done they form a joint that is practically root-proof.
They are more expensive than cement mortar.
For molding hot compounds, a clay dike, or funnel, built about 3 inches
high around the triangular opening at the top of the jointer greatly
aids in the rapid and complete filling of the joint space. A hot joint
must be poured continuously, otherwise a seam may develop between
successive pourings.
Bituminous compounds make a slightly elastic joint. A joint in 4-inch
pipe requires about 3/8 to 1/2 pound of compound and in 6-inch pipe
about 1 to 1-1/2 pounds.
Sulfur-sand joints are hard and inelastic. The compound is made by
mixing together equal volumes of ordinary powdered sulfur and very
fine clean sand, preferably the finest quicksand, and then heating
the mixture until the sulfur melts. A 4-inch joint takes about 3/4
pound and a 6-inch joint about 1-7/8 pounds of the mixture. Commercial
sulfur-joint compounds also are available.
[Illustration: Figure 3.--Jointing sewer pipe. _A_, Using
calking iron to force packing into joint. _B_, Making joint with 1:2
portland cement mortar. Use only enough water to dampen the mix. Recalk
after half an hour, to close shrinkage cracks. _C_, The completed
joint. Wrap finished joint with cloth and keep dampened, to aid
curing. _D_, Joint made by pouring 1:1 Portland cement grout of creamy
consistency into a form. This type of joint is not feasible unless the
metal forms shown are available. _E_, Use of asbestos runner clamped
around pipe, for pouring hot joint. _F_, Clay roll used in place of
asbestos runner. _G_, A completed bituminous joint. _H_, Use of swab,
to remove any joint material forced through to inside of pipe.]
Soft pig lead or old scrap lead is suitable for lead joints on
cast-iron pipe. About 3/4 pound per inch of pipe diameter is generally
required for each joint. The lead is hot enough to pour when it begins
to char the paddle used to skim off the impurities. When it cools it
must be calked tightly to take up shrinkage. The calking should be
uniform around the entire joint and should stop when the lead is tight.
Heavy pounding or continued calking may crack the bell of the pipe.
It is easier to get good, joints when the pipe is in a vertical
position. Therefore, two lengths of pipe are frequently joined and are
then laid as a single unit in the trench. In using terra cotta pipe,
this procedure may be followed only when the joint is made with a
mastic compound. Cement-mortar joints cannot be used in such cases.
Before filling the trench, the sewer should be tested to detect
possible leaks. Earth free from rubbish and large stones should then be
tamped around and about 1 foot above the pipe.