A few decades of experience at waterproofing damaged and spliced trailing
cables in underground mines yields the following methodology:
1. Wrap the area to be waterproofed with two layers of Scotch 33+. Start
in the middle of the area to be covered. Wrap to one end of the connector,
then, reverse the pitch of your spiral wrap and, without breaking the tape,
wrap to the other end. Reverse the pitch again and finish back where you
started, in the middle of the connector. This method leaves only one end of
the 33+ exposed - reducing the chance of unravelling from adhesive failure
(and, wind teasing) by 50%.
2. Apply 3M type 130C self vulcanizing tape. Stretch the tape to 50% of
it's original width when applying, and, apply the tape with the 'sticky'
side up, which is counterintuitive. Each wrap of the tape should overlap
the preceding wrap by 50%. As before, start in center of the connector,
work to one end, reverse, then, back to the center.
3. Cover the entire area - plus a little overlap (1/2" to 3/4") on each
end - with 33+ per step 1, above.
The initial layer of 33+ ensures that, should you ever need to open the
connection, you can do so without having to fight with a gooey, vulcanized
mess. The initial layer of 33+ will allow you to cut the the various tape
layers away cleanly. The top coating of vinyl tape is for abrasion
resistance, and, to protect the soft 130C tape from sun and wind.
If this is done correctly, the connector will withstand many years of
weather. Scotch 130C is available from a variety of sources, and, while it
can be pricey, in my opinion it's worth the extra $. The option, having to
replace a water-soaked feedline, is even more costly, tower-climbing labor
and aggravation notwithstanding.
We tried shrink tubes - both hot (flooded) and cold - for a few years. None
of those schemes provided the safety (of workers) and protection (of the
cables) afforded by the foregoing method. If repairs had to be made to
shrink-tube protected areas of the cable, removal of the shrink tubes wasn't
an option.
73, Brad, W9FX
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