Oxy/Acetylene

[TWINKLE_TOES]

Gordon,
<font color=blue>I'll go along with the dangerous</font color=blue>

Me too. Thanks for the welding tips./w3tcompact/icons/smile.gif

I first saw the "refilling from another cylinder" procedure in a boating book by Nigel Calder. I dug it out and thought I might add a few lines from that procedure to what you have said.

1. The cylinder to be filled is placed upright, with its valve closed, below the refilling cylinder.
2. The connecting hose is screwed to the refilling cylinder, which is then inverted above the cylinder to be refilled.
3. The connecting hose is attached loosely to the cylinder to be refilled, and the valve on the full cylinder is cracked just enough to blow a little gas at the loose end of the connection, which is then snugged up(this purges the hose of air)
<font color=red> The next step is the primary reason for my post</font color=red>
4. Both cylinder valves are opened wide. Since the fluid in the full cylinder will be at the valve end , this liquid will flow down to the lower cylinder. The rate of flow will be slow(depending on the size of the hose and other things)-it will probably take several hours to get even a moderate full cylinder.

The article continues with ways to speed things up by heating the upper cylinder..hot water and towels.

Propane would have to be a long ways away before I would try this approach. I think I probably would just use the full cylinder./w3tcompact/icons/wink.gif

 

[gordon]

Once again I would have to add a couple of things to this post. <font color=red>Both cylinder valves are opened wide. Since the fluid in the full cylinder will be at the valve end , this liquid will flow down to the lower cylinder. The rate of flow will be slow(depending on the size of the hose and other things)-it will probably take several hours to get even a moderate full cylinder.
</font color=red>

That depends---You see if you have both your valves open wide the pressure in both tanks will be the same then the only thing to do is transfer the liquid. This can be done pretty quickly. Even at it's slowest a few hours sure beats using a torch to burn of the propane in the tank to work on it!!! A #54 orfice is the largest you can use for a torch to burn off the propane vapor so that can take a few days, as compared to a few hours.

But as to filling a smaller tank myself ---forget it.

The reason for hot towels is to keep the propane from freezing up the tank and boiling. The larger the wetted surface the less chance you have of freezeups. Propane boils at/-144?.

This is not legal but lets just say I've seen it done before /w3tcompact/icons/blush.gif If you take a 30 lb tank thats full and open the bleeder up and also open the valve up after about 30-45 minutes the tank will be boiling. You can remove the valve and install a new valve. You will still have between 1/4 and 1/2 of a tank once it thaws out again.

Propane is pretty interesting I used to work with it on a daily basis when I was working on R/Vs.

Gordon

 

[richfromPA]

hey wingnut,
i would buy your own cylinders. here at work we pay alot for the rental, and my uncle is always whinin about it. as far as the propane vs acetylene, unless you want to gas weld i would go with propane. we have both at work and i prefer the propane in a heartbeat. the only time i use the acetylene is when i silver solder something. the propane will cut anything that you would wanna cut. let me say just one more thing, make sure yer careful with cylinders. they are "sleeping giants". i you were to knock the top off a cylinder of compressed gas, they have been known to fly a mile and have crashed thru cinderblock walls. whatever you get, make sure those puppys are chained securely. also if you haul them, remove the gages and put the saftey caps on. have fun.
rich

 

[Bird]

<font color=blue>they have been known to fly a mile</font color=blue>

The biggest explosions I've ever witnessed in person was at a fire at one of the welding supply dealers in the mid-60s. I don't know just exactly what caused the biggest single explosion, right up through the middle of the roof of the building; looked like a miniature atomic explosion and mushroom cloud going up. But individual cylinders kept shooting out of that building, right through the walls, just like rockets. I was peeking around the corner of a building, perhaps a hundred yards away, when one of the cylinders cut through the power lines right over my head and it was still rising the last time I saw it. An awesome sight.

Bird

 

[richfromPA]

bird,
the weld shop in delaware where i bought my last welder had a full size bottle that had nitrious oxide in it. the bottle was being hauled in a car full of college kids partying when they were involved in an accident. they guy said it exploded and i didnt even ask how many got hurt but it didnt look pretty. i dont mean a small bottle, i mean the 5 footer type. i know one thing, i wouldnt want to be on the receiving end of a flyin cylinder.
rich

 

[Harv]

<font color=blue>i wouldnt want to be on the receiving end of a flyin cylinder</font color=blue>

Okay, that prompts me to tell my story --

Years ago, I arrived at the scuba shop to have my tanks filled. I had noticed a crowd of people gathered 'round a car in the parking lot, but it wasn't until I went inside that I saw and heard "the rest of the story" (as my namesake, Paul Harvey, says).

It seems someone broke the cardinal rule about "never leave a full scuba tank standing on end", and sure enough, it happened. The tank got knocked over and the valve hit the edge of something solid and cracked off. The resulting 3,000 psi air rocket took off through shelves of merchandise, didn't slow down at all as it blasted through the cinder-block wall, jetted across the parking lot and lodged itself in the passenger door of a parked car. As blunt as the bottom of the bottle was, it was impaled in the door like a factory option.

Needless to say, that made a big impression on me, especially since my recreation at the time involved strapping one of these things to my back. This particular story had a relatively happy ending since no one was hurt, but there are many other stories with more tragic outcomes. /w3tcompact/icons/frown.gif

 

[Bird]

Harv, I'm just sitting here trying to picture what it would look like if that valve got knocked off while that tank was strapped to your back./w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif If you were standing up at the time, how deep in the ground would you go? And if you were bent over, I can just see you flying backwards./w3tcompact/icons/laugh.gif

Bird

 

[Harv]

<font color=blue>I can just see you flying backwards</font color=blue>

I had a chance to try on a set of high-tech bottles which were smaller in diameter and a little longer than the old kind. You'd wear 2 or 3 of them all plumbed and fitted together to fit very closely to your back. What I found interesting was that the valve was placed at the bottom of the pack for ergonomic reasons.

Or was it so you'd fly forwards? /w3tcompact/icons/wink.gif