Hi Kevin,

Pipe threads are made to be an interference fit, so most any sealant
will be squeezed out enough to make electrical contact.  I've used
non-hardening Permatex, Hylomar, and even Teflon tape.  On the pressure
sensors that are about 1 1/2 inches in diameter I've used a hose clamp
to connect a ground wire to the outside body of the sensor.  I had to
do that for the water pressure sensor as it was connected to a fitting
on the end of a rubber hose so it wasn't grounded at all.  I think the
Permatex does the best job.  Teflon tape works best with 6 or 8 layers,
although I still think the pipe threads will usually cut through it
enough for electrical contact.

The main objection I have to Teflon tape is keeping the little bits of
Teflon out of the system the first time you have to remove the sensor.

Bob W.

On Sun, 24 Jan 2010 13:56:19 -0800
"kevin lane" <n3773@comcast.net> wrote:

> the directions with my sender units say to not use teflon tape, so as to insure a good grd connection.  it seems I should be using some type of sealant.  what is the std practice?
> when are we going to all metric?  I tire of figuring out which is imperial or not.  I remember in 3rd grade [1963] talk of conversion, driven by the space program.   plus, why can't they stamp the wrench size on the heads of bolts?    kevin


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