It's not intended to be a do it yourself exercise working on propane tanks,
people who do it are taking responsibility on themselves and may be
skirting the regs.  I've done it and would again, but I would certainly not
want to outguess the pros on this.

Yrs,
d

On Thu, Mar 23, 2017 at 8:33 PM, Brett Ne <brettn777@gmail.com> wrote:

> Disclaimer: I'm not a propane person.  I really question the need for
> purging and, if it were that dangerous to not purge the tank before use,
> the tanks would surely come from the manufacturer filled with inert gas for
> liability reasons.
>
> 1.  Yes, at some point during filling, there will be a gaseous mixture
> capable of ignition.  That ignition would require a spark.  Where is that
> spark going to come from?  It's a steel tank whose only moving part might
> be a float, which is probably made from brass.  The filling apparatus is
> also brass, a non-sparking metal.  Even if a lightning bolt hit the tank,
> the tank acts as a Faraday cage that prevents the current from passing
> inside the tank cavity.
>
> 2.  Even if somehow the mixture does ignite during or after filling, there
> really isn't that much oxygen in that space and the resulting pressure
> shock wave is not going to be that great.  The steel tank is designed to
> hold a high amount of pressure.
>
> I may be wrong, and if so, I'd like to be corrected.  All this talk of
> playing around with filling and draining the tank with propane vapor sounds
> far more dangerous than filling an unpurged tank with liquid propane.
>
>
> Brett
>
> On Thu, Mar 23, 2017 at 4:15 PM, David Beierl <dbeierl@attglobal.net>
> wrote:
>
>> I've been poking around a little.  One purge method is to pull a vacuum on
>> the tank and allow it to fill with propane vapor; another is to fill with
>> propane vapor and vent to atmosphere "several times" -- sounds like that's
>> what your outfit did.  That's perfectly sensible, not the same at all as
>> filling five times with liquid propane.
>>
>> Yrs,
>> d
>>
>> On Wed, Mar 22, 2017 at 6:45 PM, Neil2 <vidublu@gmail.com> wrote:
>>
>> > I'd never visit that place again.  Insane there are places operating
>> like
>> > that (5x).
>> >
>> > On Wed, Mar 22, 2017 at 10:52 AM, David McNeely <davmcneely40@gmail.com
>> >
>> > wrote:
>> >
>> > > Hmmm..... .  I bought a new GoWesty tank and had it installed
>> locally.  I
>> > > asked the mechanic where to have it purged, and he recommended a
>> local RV
>> > > dealer.  I took it there.  I am certain that the place did not use a
>> > "purge
>> > > kit."  The person who first was going to do it said that he had to
>> simply
>> > > fill it, empty it, and refill it again.  I was dubious, and asked the
>> > shop
>> > > foreman, who said no, it required five times.  So, that is what they
>> did.
>> > > There was no portable tank involved.
>> > >
>> > > I have not used the propane since.  I plan to use it in two weeks from
>> > > now.  What do I do to make sure the tank is safe?  This was not a
>> small
>> > > expenditure, but I did it for safety.  Now I am not confident that it
>> is
>> > > safe.
>> > >
>> > > mcneely
>> > >
>> > > On Wed, Mar 22, 2017 at 10:32 AM, Stuart MacMillan <
>> stuartmacm@gmail.com
>> > >
>> > > wrote:
>> > >
>> > > > I've been using a Worthington 3lb tank for a couple of years. I love
>> > it,
>> > > > and it fits nicely under the seat. I now carry one 1lb bottle for
>> when
>> > it
>> > > > runs out, but if you weigh it after use, you can usually avoid
>> running
>> > > out.
>> > > >
>> > > > Just take it to a propane filler, it purges with the fill. They open
>> > the
>> > > > release valve and air is pushed out and replaced with liquid propane
>> > and
>> > > > vapor. I don't think you'll be able to fill it yourself since modern
>> > auto
>> > > > stop portable tanks do not allow rapid flow from the valve, and I
>> also
>> > > > think the auto stop float will shut off the tank when upside down.
>> > > Besides,
>> > > > it's not a good idea, and not even worth the trouble even if you
>> could.
>> > > >
>> > > > Those safety features were designed to protect us from ourselves!
>> > > >
>> > > > Stuart
>> > > >
>> > > > -----Original Message-----
>> > > > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> > Behalf
>> > > > Of Neil2
>> > > > Sent: Wednesday, March 22, 2017 10:02 AM
>> > > > To: vanagon@GERRY.VANAGON.COM
>> > > > Subject: Re: advice on new propane tank
>> > > >
>> > > > David,
>> > > >
>> > > > Please tell the kids on FB since this could save a Vanagon, er a
>> kids
>> > > life
>> > > > I mean!
>> > > >
>> > > > On Wed, Mar 22, 2017 at 6:09 AM, David Beierl <
>> dbeierl@attglobal.net>
>> > > > wrote:
>> > > >
>> > > > > They're full of air to start.  That's too lean to burn.  In use
>> > > > > they're full of propane which is too rich to burn.  You have to
>> get a
>> > > > > new tank past the point of containing an explosive mixture before
>> you
>> > > > > can use it or the first time you light something it could flash
>> back
>> > > > > through the lines and blow the tank apart.
>> > > > >
>> > > > > Yrs,
>> > > > > d
>> > > > >
>> > > > > On Wed, Mar 22, 2017 at 6:36 AM, Roman Haag <romanhaag@ymail.com>
>> > > wrote:
>> > > > >
>> > > > > > So a new tank needs to be purged?  I did not know this.
>> > > > > >
>> > > > > > Sent from someone's plumbing
>> > > > > >
>> > > > > >
>> > > > > > > On Mar 22, 2017, at 01:37, David Beierl <
>> dbeierl@ATTGLOBAL.NET>
>> > > > wrote:
>> > > > > > >
>> > > > > > > Off the cuff -- I'd take it to any propane place to purge.
>> > During
>> > > > > > purging
>> > > > > > > at some point there will be an explosive mixture in the tank,
>> you
>> > > > > > > don't want to be around if it finds a spark.
>> > > > > > >
>> > > > > > > Yrs,
>> > > > > > > d
>> > > > > > >
>> > > > > > >> On Tue, Mar 21, 2017 at 9:32 PM, gary hradek <
>> hradek@yahoo.com>
>> > > > > wrote:
>> > > > > > >>
>> > > > > > >>
>> > > > > > >> I just bought a Worthington Pro Grade 4.25 lb. Empty Propane
>> > Tank
>> > > > from
>> > > > > > >> Home Depot to use with my Colemanstove.   The 1 pound
>> cylinders
>> > > are
>> > > > > > >> nowclose to 8 dollars a piece.   I was goingto fill it from
>> the
>> > 20
>> > > > > pound
>> > > > > > >> tank but they say something about purging it.   Can I just
>> fill
>> > > and
>> > > > > > empty
>> > > > > > >> it a few timeswith propane vapor before trying to fill it
>> with
>> > > > > > >> the
>> > > > > > liquid
>> > > > > > >> by inverting the 20pound tank?   I am guessing there is
>> acharge
>> > to
>> > > > > have
>> > > > > > it
>> > > > > > >> purged somewhere?
>> > > > > > >>
>> > > > > > >> Gary
>> > > > > > >>
>> > > > > > >>
>> > > > > >
>> > > > >
>> > > >
>> > > >
>> > > >
>> > > > --
>> > > > Neil2
>> > > > '82 Diesel Westfalia (Ducky)
>> > > > '86 Vanagon (SaVannah)
>> > > > '08 170" 2500 Mega Roof Sprinter (Moby)
>> > > > '90 Westfalia Subagon (SaL)
>> > > > Fulltiming since August 2008
>> > > > Nunquam Pendite Divendium
>> > > >
>> > >
>> >
>> >
>> >
>> > --
>> > Neil2
>> > '82 Diesel Westfalia (Ducky)
>> > '86 Vanagon (SaVannah)
>> > '08 170" 2500 Mega Roof Sprinter (Moby)
>> > '90 Westfalia Subagon (SaL)
>> > Fulltiming since August 2008
>> > Nunquam Pendite Divendium
>> >
>>
>
>
>
> --
> Brett in Portland, OR
> "Albert" '82 VanaFox I4 Riviera
>