On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.

On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.

On Mon, 24 Feb 2014 18:05:10 -0500, "Mr. Luddite"
wrote:

On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.


===

I had some experience with high vacuum work many years ago near the
beginning of my adult life. It was a high energy synchrotron
particle accelerator at Cornell University and had a magnet ring 1/2
mile in circumference. There was a vacuum chamber running through the
middle of the magnets where the actual particle acceleration took
place.

http://www.chess.cornell.edu/Outreac...sMacCHESS.html

http://www.cornell.edu/outreach/prog...programid=1801

On 2/24/2014 6:55 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 18:05:10 -0500, "Mr. Luddite"
wrote:

On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.


===

I had some experience with high vacuum work many years ago near the
beginning of my adult life. It was a high energy synchrotron
particle accelerator at Cornell University and had a magnet ring 1/2
mile in circumference. There was a vacuum chamber running through the
middle of the magnets where the actual particle acceleration took
place.

http://www.chess.cornell.edu/Outreac...sMacCHESS.html

http://www.cornell.edu/outreach/prog...programid=1801


The vacuum requirements in a system like that precludes use of o-rings
and teflon tape. They will seal, but they are permeable meaning the
smaller gas molecules will work their way through the teflon or o-ring
material. In systems like that, all metal seals are typically used.
They are usually copper rings used in a feedthrough called a "Con-Flat".
The fitting is stainless and has machined knife edges that, when
tightened, compress into the copper ring forming the seal.

High vacuum levels are hard to visualize. The best way to describe it
is "mean free path" which is the distance a gas molecule will travel
before crashing into another gas molecule. At atmospheric pressure,
that distance is so short to be almost immeasurable. At high vacuum
levels (like that of space) the mean free path distance is more like 3
feet or more. In ultra-high vacuum systems the distance is even greater.

On 2/24/2014 6:05 PM, Mr. Luddite wrote:
On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against
itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.



So, is the end of the tape facing the direction of twist, or away from
the direction of twist... I am confused.

On 2/24/2014 7:43 PM, KC wrote:
On 2/24/2014 6:05 PM, Mr. Luddite wrote:
On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against
itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.



So, is the end of the tape facing the direction of twist, or away from
the direction of twist... I am confused.

The end of the tape wrap will be *away* from the direction of twist to
install the fitting.

On 2/24/2014 8:02 PM, Mr. Luddite wrote:
On 2/24/2014 7:43 PM, KC wrote:
On 2/24/2014 6:05 PM, Mr. Luddite wrote:
On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against
itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.



So, is the end of the tape facing the direction of twist, or away from
the direction of twist... I am confused.

The end of the tape wrap will be *away* from the direction of twist to
install the fitting.



Good.. Cause that's the way I been doing it all my life

On 2/24/2014 7:52 PM, wrote:
On Mon, 24 Feb 2014 18:05:10 -0500, "Mr. Luddite"
wrote:

On 2/24/2014 5:06 PM, Wayne.B wrote:
On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.


Teflon tape is tricky to use properly. It is often used in the high
vacuum industry for all the feedthrough fittings that need to seal
against a vacuum equivalent to 200 miles in space to atmospheric
pressure. Too little tape, it leaks. To much it leaks. One secret is
to wrap it in the direction of the thread, so when you are tightening
the connection fitting, the tape is not being stretched back against itself.

We couldn't use Teflon paste because it never completely cures and would
outgas into the vacuum.


The vacuum in outer space is 14.7 PSI if you maintained 1 BAR in the
vessel. . That is not really much. The galvanized piping in my shop
air system runs 150 PSI and it is tight.
I have done plenty of piping with teflon tape and this is really the
first time I had a problem. When I put the calipers on the fitting it
was about .040-.050" bigger than the threads on a female adapter at
the top of the stack.
I have an incident open at Hayward but they haven't come up with an
answer.
Using the pipe nipple does seem to be a good work around tho. I wish I
had started out that way and this would have been a 45 minute project,
not 4 days.


In a high vacuum chamber the delta P is not the issue. The issue is
prevention of any gas molecules leaking or permeating through seals into
the vacuum.

An air compressor system or a water tight fitting can still have a leak
that looks like the Grand Canyon in terms of an opening to a helium gas
molecule and will prevent the vacuum chamber from achieving it's
ultimate vacuum state. A good vacuum cleaner can draw a vacuum that is
14.6 PSI delta. It's getting to 14.66666666666669 that is difficult.

On Mon, 24 Feb 2014 17:06:45 -0500, Wayne.B wrote:

On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.

The directions that come with the compression fittings I've bought or looked at said to use no tape
or compound.

On Mon, 24 Feb 2014 18:45:41 -0500, Poco Loco
wrote:

On Mon, 24 Feb 2014 17:06:45 -0500, Wayne.B wrote:

On Mon, 24 Feb 2014 16:46:48 -0500, wrote:

I am starting to prefer the teflon paste.

===

Yes. I just finished a fairly complex plumbing job on the boat (new
distribution manifold for 4 zones of A/C cooling water). It has more
than 15 individual pipe joints and is driven by a 1 hp pool pump so
there is lots of pressure and lots of opportunity for leaks. Knock
on wood, everything worked fine with no leaks first time it was
powered up. I've always used teflon tape previously but I've had my
share of failed joints with that.

The directions that come with the compression fittings I've bought or looked at said to use no tape
or compound.

===

That's absolutely correct for compression fittings. My fittings were
NPT (National Pipe Tapered Thread), a standard since 1864.

http://en.wikipedia.org/wiki/National_pipe_thread