Date:         Sun, 7 Jun 2009 02:34:25 -0400
Reply-To:     Bill Glenn <idahobill@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Bill Glenn <idahobill@GMAIL.COM>
Subject:      Re: Propex and getting gas tight fittings
Comments: To: Ed Wiebe <wiebeis@SHAW.CA>

On Sat, 6 Jun 2009 11:33:33 -0700, Edward Wiebe <wiebeis@SHAW.CA> wrote:

>I recently decided to go for a Propex heater for my 1990 Wesfalia.  I
ordered it from Frank Condelli and got quick efficient service.  Thanks,
Frank.
>I have installed it into that little space just before the Water tank.  It
is very tight and one has to move the electrics around a bit.  It is in,
but here is my problem.  I put in a tee joint on the fridge propane line
under the sink area.  How does one get non leaky joints on these lines?  I
understand one is not to use Teflon tape and one is not to over tighten the
nuts.  What is the secret to getting them gas tight?
>Any help appreciated.
>
>Ed Wiebe

No secrets, just good practice:
1. Smooth cut.
2. Ream the interior of the cut, but don't over-do it.
3. Install the flare nut. Use long flare nuts only for gas; short flare
nuts are for water, refrigeration lines, etc. Long flare nuts also have
greater vibration resistance.
4. Proper placement of the tubing in the die; exactly flush with the face
of the die will make a flare of the proper size.
5. Flaring is a cold-forging process, which will benefit from the smallest
amount of oil between the mandrel (the cone-shaped part of the flaring tool)
and the copper. Oil is not absolutely necessary, but beneficial.
6. Do not use excessive force in forming the flare; a too-thin flare may
result, with small splits on the end
7. The thinnest film of oil on the end of the tubing and the threads of the
nut will also aid in the proper tightening of the nut.  As the brass nut
begins to tighten against the copper tubing, the film of oil will reduce
the friction between the two materials, and allow for a better feel of the
amount of torque being applied.  Again, the oil is not absolutely
necessary, but it helps.  Over-tightening flare fittings may result in the
splitting of the tubing; just snug with a wrench, plus 1/6 turn is the rule
of thumb.
7. Always test for leaks, at greater than operating pressure when possible.

Thread sealant, be it pipe dope or Teflon tape, has no place with flare
fittings.