TARRING OF ROPE YARNS AND OF SMALL ROPES
In the last chapter we described the spinning of rope yarn. Let us now
turn to the process where, for certain ropes, this yarn is treated with
the tar, the manufacture of which we have already discussed.
To penetrate and adhere to the yarn the tar must be heated to 200° or
over. This work is begun in tanks from which the liquid feeds into
the long copper-lined troughs where the tarring takes place. Through
these “coppers,” so called, run steam pipes to further regulate the
temperature. Excessive heating would cause the loss of the tar’s good
qualities, and to prevent this the supply in the “coppers” must be
freshened frequently.
The picture on the next page illustrates how the yarns unwind from the
bobbins, onto which they have been wound in the spinning process, and
pass on into the “copper.” The plates which keep the yarns under the
tar are shown elevated above the surface to give a clearer idea of
their operation. As the heavily saturated yarns come from the “copper,”
they are compressed between two rollers, adjusted to leave in the yarn
as much or as little tar as needed for the particular goods being made
and to turn back the surplus.
The pull which carries the yarn through the tar and between the rollers
comes from two large drums around which the yarns travel preparatory to
reeling onto friction-driven receiving bobbins.
Goods of nine-thread size and under are usually tarred in the completed
rope form, but the process is essentially the same as with the yarns.
Visitors to our tar-houses frequently remark upon the rich golden brown
of our tarred goods. Those who use and sell them have come to look upon
that color--an outward sign of right materials and methods--as the
Plymouth mark of the weather-resisting qualities contained in the goods.
[Illustration: YARNS ENTERING THE “COPPER”]
[Illustration]