[TheForge] old propane tanks

Tue Sep 27 22:40:51 EDT 2011

40 plus years ago,  my dad and I cut up a lot of those tall 100 pound
propane tanks to make hog feeders. We marked our lines, pulled the valve
and filled them with water, and cut them in half the long way.  I was mid
to late teens.  My dad was a marine engineer, and cautioned me never to
weld or cut a fuel oil tank,  but he didn't have any qualms with old
propane tanks.

Respective to fuel oil tanks, my cousin had one of her photos get national
coverage with UPI /United Press.  Guessing now that this was middle 1990s,

She was taking photos of a grass fire for the Winterset Iowa newspaper, 
The fire department had been called. They saw a scrapper guy using a
cutting torch on a big fuel tank.  I am guessing at the numbers now, but
say it was a 10,000 gallon tank.  The fireman that went to get the
scrapper to stop cutting was killed along with the salvage iron scrapper. 
My cousin got her photo by chance, just as everything blew.

Dann

> Freon can be VERY dangerous heated or in moderately high concentrations.
>
> When we did something with a propane tank we'd pull the valve and fill it
> with warm water and a little chlorox, about 1 cup for a 20 lb tank and so
> on. The clorox clears the mercaptins so it stops stinking. then we drained
> it and did whatever. Unlike gasoline or diesel fuel, propane doesn't leave
> a
> residue in the tank, the only residue is the waxy mercaptins and that's
> just
> an odorant.
>
> Heck, as kids we used to try to get propane tanks to explode to no avail.
> Even putting a full tank in a fire didn't do much of anything, it just
> spurted a largish flame from the pressure relief. We got tired of pulling
> the valve and lighting the residual propane, all it ever did was go
> whoosh,
> not even a thud. Propane can be really dangerous in uncontrolled
> conditions
> like say your basement.
>
> Cutting an empty tank is pretty low risk but by all means do NOT do
> something that makes you uneasy, especially not on MY say so.
>
> Whatever you do, do NOT cut an empty fuel oil tank, diesel or heating oil.
> As Bruce pointed out there MUST be a flammable mixture of tuel and air to
> result in an explosion. With many fuels, gasoline for instance, it's a
> little hard to get a flammable ratio. Gasoline's saturation level is well
> above the flammable range. Meaning the point where gasoline can't
> evaoprate
> any more because the air is holding as much as it can is well above the
> flammable ratio and gas is very volatile so it's going to reach it's
> saturation level quickly.
>
> Fuel oils on the other hand have a saturation level smack in the middle of
> the flammable range. This means that unless a fuel tank is absolutely
> full,
> NO bubble of air at all, the air bubble is a fuel air bomb. Fuel oils
> reach
> their saturation level more slowly but not very. Fuel oils also leave a
> flammable residue behind that can be ignited. I don't know the mechanics
> or
> chemistry of it but washing the residue out is nearly impossible. When we
> welded on a used fuel tank all but one guy left the shop though one guy
> stayed across the road to call  EMS if neccessary. A welding shop about 3
> miles from where I was living at the time was working on a fuel truck and
> had been steamming it for three days when an old hand (NOT the guy who was
> doing the job) got impatient and just struck an ark on the cracked
> fitting.
> The explosion killed the guy adjusting a steam line on top of the tank,
> the
> "old hand" was blown through a wall into the office  and survived. The
> other
> guys in the shop escaped with injuries and burns. There were two steam
> lines
> in the tank and after three days there was still a flammable mix. It
> destroyed a 30,000 sq/ft shop, injured a bunch of people and killed one.
>
> Welding or cutting fuel oil tanks give me the willies big time but it was
> part of the job.
>
> Jer
> ----- Original Message -----
> From: "Paul Novorolsky" <crosspein at sbcglobal.net>
> To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
> Sent: Tuesday, September 27, 2011 2:09 PM
> Subject: Re: [TheForge] old propane tanks
>
>
>> Just for the record: from what I've read, freon decomposes to phosgene
>> at high temps. So while freon tanks are less likely to go boom, they
>> aren't completely "safe" either. So they too need to be handled
>> appropriately.
>>
>> Information can be found on many welding safety sites.
>> Search= phosgene freon
>>
>>
>> **paul
>>
>
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