[TheForge] Re: repost of propane cylinder cutting

Tue Nov 26 01:55:01 2002

At 10:37 PM 11/25/02, you wrote:

The propane tanks I have cut up are generally much older..often 50 years 
old or more, and they have quite a puddle  of oil and scent in the bottoms 
usually. I don't care what they say, when I heat a piece of old tank steel 
while welding it, the scent is still in or on the metal.
My cutting method is similar and so far, it has worked for me..but it is a 
risky business. After the valve  and all the plugs etc are removed, the 
tank is inverted and drained for a week before hot water and industrial 
detergent filling. The other thing I've done differently than Terry is to 
cut wet..that is to say, with the tank all the way full, with the ports at 
the very top and water flowing in when cutting the first opening in the 
top. It sputters and spits and is messy but I'm not as spooked when i do it.
Re  tank anvil stand..how bout cutting the cyl into longitudinal quadrants 
and them reversing them and gluing them back together? That way you have a 
concave sided stand that fits closer to the anvil base and lets you step in 
closer to the anvil while working.

I drove a couple of hours south today following  postings in the local 
greasy-ad handout. Bought a set of  4' sheetmetal rolls ,most of a 25# 
hawkeye helve hammer, 2 mid sized post vises. some line shaft stuff, a 
giant flat belt drill press and a fair sized wall mount, hand crank drill 
press plus a 3' bellows and some misc for about  $350 today.... Best in a 
long time. It all needs some work..but hey, so do I...Pete

>hello;
>
>i have debated this numerous times with the propane service
>companies here. i tend to believe that the slight amount of
>rust internal to the cylinder is what has absorbed the propane
>and/or the mercaptan. they still say it is the cylinder's steel.
>i guess it is really a mute point since i have seen it where a
>cylinder has been purged with water, dish detergent, and bleach,
>shoot a four foot flame out the value hole when a oxy-fuel torch
>just pierced the cylinder.
>
>i am still working a design to cut the cylinders with a basically
>a large pipe cutter. many cutting wheels in a roller chain straped
>around the cylinder. have not had much time this year to work on it.
>
>i did see one a fellow made that used a roller chain to guide the
>oxy-fuel or plasma torch around the cylinder. a trolley with air motors
>driving the wheels followed the roller chain. the trolley holds the
>cutting torch.
>
>On Mon, 25 Nov 2002, Mike Spencer wrote:
>
>mike>
>mike> Thanks, Terry.  Saved as a manpage for easy access.
>mike>
>
>terry> scrap lift truck cylinders, roofer cylinders,
>terry> plumber cylinders are different cylinders
>terry> and need to be treat differently. i will cover
>terry> those in a separate post.
>
>mike>
>mike> Didn't know that.  I'll watch for the post.
>mike>
>
>terry>    propane cylinders absorp some of the ethyl
>terry>    mercaptan that is used to give propane an
>terry>    odor. they also absorp some propane.
>
>mike>
>mike> I'll take your word for this for the sake of safety but I don't
>mike> understand it.  Wood is a porous composite.  Sintered metals are
>mike> porous.  Plastics can adhere monomolecular layers of (even partially)
>mike> non-polar substances.  I don't get how sheet steel and "absorb"
>mike> relatively simple organic stuff like propane or ethyl mercaptan.  Is
>mike> this related to the (potential) formation of highly sensitive and
>mike> explosive metal-acetylides?  Doesn't seem to me like it would be
>mike> because the unique triple bond of acetylene is missing.
>mike>
>mike> - Mike
>mike>
>
>and, yes that is 'the fish'.
>
>--
>Terry L. Ridder ><>
>
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