Subject: Re: cylinders

From: [email-masked] (Katana ---/-----------)
Date: Tue, 24 Sep 1996 01:56:29 GMT

What about this approach: 
1. Don't use a cylinder that had flammable gas in it in the first place,
try argon or CO2 or air. 
2. If you have to mess with another kind, let out the gas, remove the
valve, fill the open cylinder with water, rinse it out, fill it with water
again, and then cut it while it is filled with water. 
This is for the sake of conjecture - I am not advising on doing this, just
putting it out for comment. 
-- 
               Bill Wyant 
   Bladesmith / Art Blacksmith 
Avalon Ironworks, Ft. Wayne, IN 
    [email-masked]

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From: Michael Spencer <[email-masked]>
Date: Tue, 24 Sep 96 00:41:06 EDT

Bill Wyant wrote:

> ...fill it with water again, and then cut it while it is filled with
> water.  This is for the sake of conjecture - I am not advising on
> doing this, just putting it out for comment.

This works fine. I've done fast weld jobs on gas tanks this way. Fill
completely with water. A vapor space of an ounce or two filled with
inflammable vapor can make quite a little bang and that risk demands
good eyewear.  If you have to get the water out of a closed tank (like
a freshly welded gas tank), slosh it out a half dozen or more times
with a half a cup of acetone. It will mix with the water and the last
rinse will leave just acetone in the tank.

But I dunno if I'd want to try this with an acetylene tank bacause I
don't know just how some residual acetylene dissolved in some acetone
and trapped in the porous matrix (despite attempts to rinse it out)
might behave. Acetylene is very unstable stuff.

About the risks of acetone: "volatile" and "inflammable vapor" are the
keywords. Do the acetone rinse number outdoors away from
flames. Especially not in a shop with a wood stove going. ;-) You
don't really have to worry about the disposal of small quantities of
acetone. Whatever you do, it'll end up evaporating. The health risk
from occasional or intermittant exposure to the vapors isn't
great. Other common solvents such as toluene, benzene and xylene
deserve far more caution.

And for the curiosity shop: Old, much used *copper* acetylene
generator tanks are potentially explosive even when apparently
perfectly "clean" and dry. Solutions of copper or silver salts react
with acetylene to form copper acetylide and silver acetylide, both
impact-sensitive explosive compounds. An old copper acetylene
generator can have a buildup of copper acetylide in the seams, so that
hammering them up to tighten them can cause small but significant
explosions.

- Mike

-- 
Michael Spencer               (902) 543-8375
[email-masked]
URL: http://www.mit.edu:8001/people/mspencer/home.html
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