[TheForge] cutting propane cylinders

[Steve Smith]

Here's what I've saved from the past:
=======================
Shannell Sugrue:
I just fill with water and plasma it.
=======================
Terry Ridder:
hello;

this posting covers standard cylinders used on
gas grills and rvs.

scrap lift truck cylinders, roofer cylinders,
plumber cylinders are different cylinders
and need to be treat differently. i will cover
those in a separate post.

warning, note.

cutting scrap propane cylinders is dangerous,
there is no room for mistake here. generally
with a mistake here someone is either severely
burned or someone is killed. (this basically
applies to any type of scrap cylinder)

assuming you have a scrap propane cylinder this
is were is begin.

0. does this outdoors or in an extremely well
    ventilated building. i generally do this at
    night when the cylinder has had a chance to
    cool down.

1. make sure that the cylinder is really empty.
    using a weed burner attached to the tank
    burn off any propane left in the cylinder.

    with the older type 1 values on cylinders
    this gives you reasonable assurance that
    the cylinder is in fact at 0 psig. this
    does not mean that the tank is empty of
    propane vapor. repeat this does not
    mean that the tank is empty of propane
    vapor.

|  with some type 1 and all type 2 valves on
|  cylinders there is a venting screw on the
|  valve itself. loosing this screw should
|  vent propane vapour. venting propane should
|  be done outdoors and away from any source of
|  ignition.

    with the newer opd (overpressure protection
    device) values this gives you some indication
    that the tank should be at 0 psig but they
    may not be. these new opd values do fail
    and they can either fail in the open position
    or in the closed position. if it has failed
    in the open position tank pressure should be
    at 0 psig, if it has failed in the closed
    position tank pressure could be as much as
    125 psig.

2. time to attempt to remove the cylinder's
    valve. do *not*, repeat do *not* lay the
    cylinder down to remove the valve. if there
    is still any pressure in the tank when the
    value is removed the tank becomes a missle
    sliding across the ground. with the cylinder
    standing upright, secure the cylinder to a
    fixed support (tree, other cylinders, steel
    post in the ground, fence post, etc ) with
    either chain or a strap wrench-type hold down.
    turn off all radios, cd-players, tape players,
    etc you do not want an unnecessary noise.
    do *not*, repeat do *not* place your body
    anywhere over the valve. if there is any
    pressure in the tank when you begin to
    loosen the valve the risk of the valve being
    shot into your body is too high.
    using either an open end wrench or large
    adjustable wrench slowly loosen the value.
    listen for any "hissing" or "whistling".
    this indicates that there is still pressure
    in the tank. if you hear any "hissing" or
    "whistling" allow the tank to vent. go get
    coffee, tea, milk, etc. take a break.
    when the "hissing" or "whistling" has stopped
    loosen the value some more and keep listening
    for the "hissing" or "whistling".
    once you have the valve removed the situation
    is becomes somewhat safer.

3. using a water hose fill the tank through the
    value opening till it begins to over flow. add
    a couple drops of dish washing liquid to the
    water. this breaks the surface tension of the
    water and allows the water to reach more of
    the cracks and crevices inside the cylinder.
    let the cylinder sit for 48 hours to a 5 days
    with the water and dish washing liquid in it.
    propane cylinders absorp some of the ethyl
    mercaptan that is used to give propane an
    odor. they also absorp some propane. the
    water will cause some of this to come out
    of the cylinder walls. after the 48 hours to
    5 days, dump the water out. it will probably
    look pretty digusting.

4. fill the cylinder with just water this time.
    you want to fill it to with in an inch of where
    you want to cut the top off. the reason for this
    is that if there is still some propane and ethyl
    mercaptan in the cylinder walls. it will ignite.

5. using either a oxy-fuel torch, plasma torch,
    grinder, etc begin to carefully cut the top
    off. do *not*, repeat do *not*, place your body
    over the valve opening. if the residual propane
    ignites it is going to flame out of the valve
    opening. you can be burned. once the top is
    removed you can dump the water out.

6. cutting the bottom off is now a simple task.


rules to remember:

1. safety comes first.
2. see rule 1.
3. propane can either burn you, freeze you,
    or sufficate you.
4. keep extraneous background noise from
    radios, cd-players, tape players, etc
    to a minimum.
5. do *not*, repeat do *not* do this when
    your spouse is around. if they are anything
    like mine, they hate the smell of propane. ;-)
    ( women just have a better sense of smell
      then men do, i guess. )
6. do *not* do this if there clothes hanging out
    on the "solar" clother dryer (clothes line).
    ;-) you will be washing the clothes over
    again and again to get the mercaptian
    odor out of them.

-- Terry L. Ridder ><>