Greg wrote:

One other trick is to coat the connector with RTV, then slide
the heat shrink over it and apply the heat. The shrinking heatshrink pushes
out the excess RTV and makes a very water tight seal after it cures.
Good luck with it,

Any seal that relies on RTV will take more than luck. RTV will fail to
seal and water will wick into the connection and destroy it. It is as
predictable as sunrise.

There are many off the shelf connectors and sealing materials for that
application and nearly all of them are far superior to any of the
silicone adhesive sealants so often misused by the DIY'er.

Rick

Rick,
The phone companies and the Navy have used RTV for years to make sealed
connections on cables and it will not wick as badly as most off the shelf
connectors will, if done properely. These are for both aerial and
sub-surface applications. I have used it with Canon and Amphenol
multi-conductor cables as well.

As a guess, you have no direct experience using it? If so, tell about what
you actually did?
Greg.

"Rick" wrote in message
link.net...
Greg wrote:

One other trick is to coat the connector with RTV, then slide
the heat shrink over it and apply the heat. The shrinking heatshrink
pushes
out the excess RTV and makes a very water tight seal after it cures.
Good luck with it,

Any seal that relies on RTV will take more than luck. RTV will fail to
seal and water will wick into the connection and destroy it. It is as
predictable as sunrise.

There are many off the shelf connectors and sealing materials for that
application and nearly all of them are far superior to any of the
silicone adhesive sealants so often misused by the DIY'er.

Rick





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Greg wrote:

As a guess, you have no direct experience using it? If so, tell about what
you actually did?

Guessed wrong. 8-)

Worked with building, maintaining, and operating manned deep
submersibles to 2000 meters, plus ROV operations and surface marine
industry for over 30 years with a break to go airline flying for a few
years between seagoing endeavors. Am still sailing in the merchant
marine and teach propulsion and sometimes electrical classes at a
maritime academy.

We made up many of our own cables for submersible work and repaired
those that we had commercially built. When I spliced a DC power cable
that supplied my life-support system a mile underwater I did not even
consider using a silicone sealant anywhere on the splice.

The only place we would use those sealants was to seal rubber gaskets in
on devices that were not subject to more than minor pressure differentials.


The RTV you are referring to may be the 2-part compound that is not
readily available to or commonly used by the DIY'er.

Common references to RTV are to the single component acetic acid and
moisture cured material found in home stores and recreational boat
shops. It will not bond to the wiring jacket and water will wick into
the splice. It will corrode the conductors. It may take a year or so
depending on how severe the exposure and how well the rest of the splice
was made but it will wick and the joint will corrode and fail.

Rick

Sooo..... What DID you use as a sealant, now that you've submitted your
credentials, and convinced us all that you know what you're talking about?


"Rick" wrote in message
link.net...
Greg wrote:

As a guess, you have no direct experience using it? If so, tell about
what
you actually did?

Guessed wrong. 8-)

Worked with building, maintaining, and operating manned deep
submersibles to 2000 meters, plus ROV operations and surface marine
industry for over 30 years with a break to go airline flying for a few
years between seagoing endeavors. Am still sailing in the merchant
marine and teach propulsion and sometimes electrical classes at a
maritime academy.

We made up many of our own cables for submersible work and repaired
those that we had commercially built. When I spliced a DC power cable
that supplied my life-support system a mile underwater I did not even
consider using a silicone sealant anywhere on the splice.

The only place we would use those sealants was to seal rubber gaskets in
on devices that were not subject to more than minor pressure
differentials.


The RTV you are referring to may be the 2-part compound that is not
readily available to or commonly used by the DIY'er.

Common references to RTV are to the single component acetic acid and
moisture cured material found in home stores and recreational boat
shops. It will not bond to the wiring jacket and water will wick into
the splice. It will corrode the conductors. It may take a year or so
depending on how severe the exposure and how well the rest of the splice
was made but it will wick and the joint will corrode and fail.

Rick

padeen wrote:

Sooo..... What DID you use as a sealant ...?

Well, it was a multistep process that started with soldered butt
splices, covered with heatshrink. The stepped splices were then wrapped
with a well stretched layer of self-vulcanizing tape and the whole was
filled with a 3M product called ScotchFil, a soft, thick, rubbery tape
that filled all the voids between the conductors. Next, the smoothed
Scotchfil was wrapped with another couple of wraps of self vulcanizing
tape until the splice was smooth and solid. Final wraps of a vinyl tape
like Scotch 33 overlapped the entire length and then that was secured
with cable wrapping thread and finally the entire splice was coated with
Scotchkote, a rubber glue type of sealant.

These splices were almost guaranteed to work to 10,000 feet. Note the
almost ...

Rick

Rick, you don't mention the deep submersibles method of routing nearly all
electrical cables inside of tygon tubing and fittings and filled with
mineral oil. The fluid is always at the same pressure as the water outside..
If everything goes as planned, the cabling is never exposed to seawater,
even at 10,000 ft.

I have built and repaired hundreds of cable assemblies for the DSVs and the
DSRVs while working for Locheed Advanced Marine Systems.

Steve
s/v Good Intentions

Steve wrote:

Rick, you don't mention the deep submersibles method of routing nearly all
electrical cables inside of tygon tubing and fittings and filled with
mineral oil.

We only used oil-filled cables for temporary of field installed systems
that didn't rate a shop made cable. We would save the plug ends and a
foot or two of wire from old cables for that purpose. We used oil-filled
j-boxes externally and ran conductors through the same type of clear
plastic tubing you see in boat stores and filled the entire run with oil.

We had a shop back in the world where we could build and vacuum pot our
own cables for newbuilds. Some of our standard cables were manufactured
by a specialty cable shop. A lot of smaller stuff just used off the
shelf underwater connectors made for the commercial (oil field)and
military market.

Rick

Steve wrote:

Rick, you don't mention the deep submersibles method of routing nearly all
electrical cables inside of tygon tubing and fittings and filled with
mineral oil.

We only used oil-filled cables for temporary of field installed systems
that didn't rate a shop made cable. We would save the plug ends and a
foot or two of wire from old cables for that purpose. We used oil-filled
j-boxes externally and ran conductors through the same type of clear
plastic tubing you see in boat stores and filled the entire run with oil.

We had a shop back in the world where we could build and vacuum pot our
own cables for newbuilds. Some of our standard cables were manufactured
by a specialty cable shop. A lot of smaller stuff just used off the
shelf underwater connectors made for the commercial (oil field)and
military market.

Rick

Rick, you don't mention the deep submersibles method of routing nearly all
electrical cables inside of tygon tubing and fittings and filled with
mineral oil. The fluid is always at the same pressure as the water outside..
If everything goes as planned, the cabling is never exposed to seawater,
even at 10,000 ft.

I have built and repaired hundreds of cable assemblies for the DSVs and the
DSRVs while working for Locheed Advanced Marine Systems.

Steve
s/v Good Intentions

Thanks, Rick. I'm an electrical contractor at the moment and your product
list is very familiar to me wrt underground splices. Soils have similar
pernicious chemical liabilities to electrical lines that seawater does, it
seems. I wondered if Scotchkote was a common marine solution.

Padeen


"Rick" wrote in message
hlink.net...
padeen wrote:

Sooo..... What DID you use as a sealant ...?

Well, it was a multistep process that started with soldered butt
splices, covered with heatshrink. The stepped splices were then wrapped
with a well stretched layer of self-vulcanizing tape and the whole was
filled with a 3M product called ScotchFil, a soft, thick, rubbery tape
that filled all the voids between the conductors. Next, the smoothed
Scotchfil was wrapped with another couple of wraps of self vulcanizing
tape until the splice was smooth and solid. Final wraps of a vinyl tape
like Scotch 33 overlapped the entire length and then that was secured
with cable wrapping thread and finally the entire splice was coated with
Scotchkote, a rubber glue type of sealant.

These splices were almost guaranteed to work to 10,000 feet. Note the
almost ...

Rick