PIPE SEAMS.
The Butt Seam on Round Pipe.
Pipes that are placed in a horizontal position are usually butt seamed,
as a stronger seam can be made in that manner. This form of seam is also
used in lengthening traps, bends, etc. To prepare a round pipe for butt
seaming, the ends of the pipe should first be made perfectly round by
inserting a drift plug and dressing the lead up close to it. The ends of
the pipe should be rasped true and then shaved clean. Also shave the
pipe for a distance of ⅛ inch each side of the edge. A piece of stiff
writing paper should then be rolled up the size of the pipe and inserted
in the ends. This paper will prevent any lead from running into the pipe
and leaving rough edges, as these afterward form an obstruction.
The burning should be commenced at the under side of the pipe, Fig. 31,
and proceed both ways from the starting point and finish at the top. If
the beginner has successfully overcome the difficulties of the seams
preceding this he will find no trouble in making a strong and
workmanlike seam on this pipe. Pipes are seldom used heavier than the
grade known as D for this class of work, and for that reason it is
seldom necessary to add lead to these seams. But if a hole should be
burned in the pipe on the under side, lead should be added to the top
side of the pipe and then made to follow the flame to the desired spot.
This will be found a quicker and more certain method than attempting to
add lead directly to the hole. A properly burned pipe should show the
full thickness of the pipe when cut with a saw.
[Illustration:
_Fig. 31.—Burning a Butt Seam on Round Pipe._
]
Through Seam on Round Pipe.
Where heavy pipe that is to be used under pressure is to be joined it
must be burned through to provide strength, and the ends prepared in the
same way as just described, but the ends must also be trimmed off all
the way around with a slight bevel reaching from the outside almost to
the inside bore of the pipe. The bevel must stop so as to allow a narrow
square butt end on each pipe. Then when a piece of paper has been placed
on the inside to prevent lead running into the pipe, the two ends when
butted will present a V-shaped groove, as shown in Fig. 32, reaching all
around the pipe. The burning is commenced at the bottom, as shown in
Fig. 31, and the two ends securely united. The groove is then filled by
burning on additional lead from a thin cleaned strip until the groove is
filled and the pipe made as heavy and strong at this point as anywhere
on its entire length.
[Illustration:
_Fig. 32.—Joint Prepared for Through Burning._
]
The Lap Seam on Round Pipe.
[Illustration:
_Fig. 33.—Preparing for a Lap Seam._
]
[Illustration:
_Fig. 34.—Burning a Lap Seam on Round Pipe._
]
This seam is used almost exclusively on pipe in a vertical position, and
is similar to the horizontal lap seam. The pipe is prepared by spreading
the lower piece of pipe with a drift plug one size larger than the size
of the pipe used. The end of the pipe intended to enter this socket is
rasped to a bevel edge, as shown at _a_, Fig. 33. This end is then
shaved clean, as is also the inside of the socket. The pipe is then
placed into the socket, which is then dressed up tight against the
inserted pipe, as shown in Fig. 34. The exposed edge is then cleaned and
burned, as described for horizontal lap seams.
The Tee Joint on Round Pipe.
[Illustration:
_Fig. 35.—Making a Tee Joint on Round Pipe._
]
With a pair of compasses set the diameter of the pipe that it is desired
to insert, and strike a circle on the pipe which is to receive the tee.
With a tap borer, or any other device, cut out a circle of lead, leaving
about ¼ inch to turn up. Then draw this remaining lead up by means of a
bending iron and a heavy piece of iron, such as a chisel, as shown at B
in Fig. 35, until the hole is large enough to receive the piece intended
for it, the end of which should be beveled with a fine rasp, as shown at
_a_. The lead should then be dressed back against the pipe, after which
remove the piece and shave clean, and proceed to burn as described for
the lap seam on round pipe, and as shown in Fig. 36. Care must be taken
in dressing up the lead flange to dress it slowly so as to avoid
weakening the lead.
Lining Tanks.
The lining of chemical tanks being the principal work of the chemical
plumber, a description of how this work is done will probably be of some
use to the beginner. In preparing lead sheets for a tank the sheets
should be cut so as to give the most seams on the bottom, because of the
greater ease in making them. In large tanks I find it convenient to put
the bottom in first, cutting it to make an easy fit, and then the sides
are put in. These are cut to allow ¾-inch lap on the bottom.
The lead sheets are laid on the floor, or some other smooth place, which
has previously been swept clean, and then dressed out smooth. This can
best be done by using the wooden dresser to take out the large wrinkles
and then smoothing with a lead flap. This flap is simply a piece of
sheet lead about 3 inches wide and 12 inches long, one end of which is
drawn into a roll to fit the hand. Then mark the laps and bend them to
the desired position. The under side of the lap should be shaved clean,
as also the lead under the lap, to facilitate fusion.
[Illustration:
_Fig. 36.—Burning in the Tee Joint._
]
If the tank is over 18 inches high the lead must be fastened to the
sides with bullseyes. These are made by countersinking places in the
sides of the tank. The lead is then dressed into these holes and it is
held in place with large headed brass screws, which are covered by
burning over the heads. Lead for the purpose is taken from lead strips.
The building up process is resorted to in covering these screw heads.
The lead should be arranged so as to avoid corner seams as much as
possible, as it is quite a difficult job to get the proper thickness of
lead in such seams. No rule can be given for cutting lead to fit a tank,
as tanks are of such a variety of sizes and shapes, and the lead is of
so many widths, that the mechanic must study how to cut the stock
without waste and have as few seams as possible.