Dave and the group,
3M makes a Scotch Brand #23 "Rubber Splicing Tape" which is also
self-vulcanizing. It is available in most large industrial electrical
supply houses.
It is rated for High-Voltage and to 130 degrees C. I used it in the
Navy to do up rf cables in the periscope housings on submarines. They
were under sea pressure, and in salt water. I never had a leak with the
ones I did.
7 3,
Rod Johnson KA7YOU CN97AK near Issaquah, Wa. 160M thru 1296 MHz
NWQRP#120 ARCI#7251
QRP-L#844
On 09 Mar 1997 10:35:07 +0000 Dave.Ackrill@westwood45.powergen.co.uk
writes:
>
> For sealing joints in the rain, try self amalgamating tape. It
>is
> usually black with a paper, or plastic, separator to stop it
>forming a
> self amalgamated blob.
>
> As you apply it you remove the paper/plastic separator, pull it
> slightly so that it stretches like an elastic band and wrap it
>around
> the connector or what ever you want to keep together. The tape
>then
> sticks to itself and forms a water proof joint.
>
> I've seen two sorts of this tape, one I call "dry" which is clean
>to
> use, the other I call "sticky" which has a layer of what looks
>like
> mastic on it and a hard outer shell. The latter was used by
>cable
> jointers when I worked as an engineer in a distribution company.
>
> The other useful form of tape is Deso, or Silglass, this is a
>horrible
> green colour, which looks like several lengths of hairy string
>covered
> in a very sticky green paste. It makes a mess of your hands, so
>I
> tend to wear kitchen gloves when using this stuff but it is
> waterproof. In the sun it will eventually dry out and become
>brittle,
> but it does keep the water out for quite a while. I've also seen
>this
> stuff used as temporary repairs on canoes and fibreglass boats.
>
> Before they were outlawed, we used to make temporary pot ends
>(ends of
> LV cables on distribution systems) using ordinary electrical tape
>as
> insulation between the phases and wrapped in Denso, then bury the
>
> joint. The idea was to go back the next day and replace it with
>a
> proper joint. You can guess what happened sometimes! PME
>earthing
> and the development of simple resin pack joints meant that the
> temporary end joint was no longer used. Still seemed to get
>through a
> few rolls of Denso, one way or another though.... HI!
>
> All these tapes are very useful in waterproofing antenna joints
>and
> ends of coax cables. Although what their performance as RF
>insulators
> is I don't know. Mind you, water ingress is a bad thing for RF
> anyway.
>
> Cheers de Dave (G0DJA)
>
>
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