Acetylene - As requested

[weldgault]

Acetylene is filled into a cylinder that is filled with a very porus material and filled with Acetone, which absorbs 25 times its volume , with acetylene, which is formed by adding water to calcium carbide and pumped into the cylinder very slowly. Acetylene = 14.7 cuft per Lb. The weight of the cylinder, with acetone added is stamped into the cylinder as TW 125#(example), then filled to 250# at 68 Degrees F. After filling, the cylinder is weighed again (150#) 25 lbs. of gas = 367.5 cuft., which is stamped on the outside of the cylinder or a tag with the amount of gas inside the cylinder is attached. You as the customer, not knowing this will except a large cylinder at a given amount (400 cuft). The LWS will be shocked if you ask them to weigh the cylinder and charge you for exactly what is in the cylinder. I hope this will answer some of the questions ask in other threads. Remember that 15#'s is the max. psi, which should be withdrawn from the cylinder and the 1/7 rule applies. Example: 400 cuft = 57 cuft that can be removed from the cylinder, without the gas becoming unstable and a #15 MFA heating head requires a min. of 90 cfh to operate correctly, so 1 large acetylene is not enough to run that rosebud, manifold 2 together, otherwise live with the backfire from not having enough volume of gas supplying the tip. More information, upon request. John Gault ( everything about me is posted).

[Shade Tree Welder]

Just to ensure clarity

...Remember that 15#'s is the max. psi, which should be withdrawn from the cylinder

15 psig should be the highest outlet pressure allowed from the acetylene regulator.

...Remember...and the 1/7 rule applies. Example: 400 cuft = 57 cuft that can be removed from the cylinder, without the gas becoming unstable and a #15 MFA heating head requires a min. of 90 cfh to operate correctly, so 1 large acetylene is not enough to run that rosebud, manifold 2 together...

You should not use more than 1/7 of the volume of the full cylinder per hour. So with a 400 cf. ft cylinder you can not safely use more than 57 cu ft per hour, assuming that the cylinder is at normal room temperature. Cold cylinders will be less.

A 120 cu. ft cylinder will supply only 17 cu. ft. per hour.

If you withdrawl more than that volume you chould aspirate acetone and have a flame thrower on you hands, this in not a safe operation and an uncontrollable fire could result.

[weldgault]

Just to ensure clarity

15 psig should be the highest outlet pressure allowed from the acetylene regulator.

You should not use more than 1/7 of the volume of the full cylinder per hour. So with a 400 cf. ft cylinder you can not safely use more than 57 cu ft per hour, assuming that the cylinder is at normal room temperature. Cold cylinders will be less.

A 120 cu. ft cylinder will supply only 17 cu. ft. per hour.

If you withdrawl more than that volume you chould aspirate acetone and have a flame thrower on you hands, this in not a safe operation and an uncontrollable fire could result.

All true, except you can withdraw more than 15 psi. It can be done with a two staqge regulator but then you would not get enough volume to run anything. Only thing I can say is STAY at 15#, or in the red zone. John

[Rick Moran]

I read this post today and because I was never formally schooled on welding, I was unaware of the dangers and reason for using any higher pressures. I don't believe I've ever turned my tank up that high (I usually just weld or braze small stuff and no cutting), but decided to put a label on my tank to serve as a reminder.

"DO NOT EXCEED 15 PSI"

Thanks for the tip.

[daddy]

Thanks for the responses fellas. I am becoming enlightened. Very informative.
How much does the one seventh rule change with cold temps? Say around 25 deg. F.

[David R]

Good stuff

Thanks
David

[mtncrawler]

I second that - great stuff, thanks for the post John.

[Rojodiablo]

John, and Ron, I have a question for you. If the acetone in the tank is aspirated, or say the bottle is run dry is the correct way to ask this- if the bottle is run dry, and left open, will the acetone inside evaporate quickly enough to need special accomodation when the bottle is refilled? Or is the acetone and acetalyne mixed at the time of filling, and the acetone is part of the product you burn through the torch? Great post guys, thanks for putting it up. I have never heard an answer to this, my welding teacher a zillion years ago just said" There's acetone in it."

[weldgault]

John, and Ron, I have a question for you. If the acetone in the tank is aspirated, or say the bottle is run dry is the correct way to ask this- if the bottle is run dry, and left open, will the acetone inside evaporate quickly enough to need special accomodation when the bottle is refilled? Or is the acetone and acetalyne mixed at the time of filling, and the acetone is part of the product you burn through the torch? Great post guys, thanks for putting it up. I have never heard an answer to this, my welding teacher a zillion years ago just said" There's acetone in it."

Acetone will not leave its home unless it is forced out by pressure or the tank is left lying down. It is not part of the burning process, it only releases the acetylene gas that is stored, in the cells of the filler in the cylinder, When the cylinder is to be refilled it is weighed and acetone is added until the cylinder weighs what is stamped on the cylinder (TW)
I hope it is somewhat clearer now, or I will try another avenue. John

[G3farms]

rojo
when the bottle is empty of acetylene and you return it to be filled, it is filled according to weight. read over the first post again it explains it good.
at the time of filling the acetone is already inside of the bottle and the acetylene gas is introduced into the bottle under pressure and the acetone soaks it up or is disolved into it. much like co2 in pop. the filling rate can only take place at 1/7 the capacity (it takes some time for the acetylene gas to disolve into the liquid acetone. thats why there is the 1/7 rule, it can only be discharged at the same rate, it takes time for the gas to come out of the liquid.
that is why acetylene bottles need to be stood up so that the acetone is not siphoned out of the bottle. that is why if an acetylene bottle is transported laying down they should be stood up for a little while before using to let the acetone settle to the bottom of the bottle (come off of the porous filler up close to the valve). although there is a certain degree that a bottle can be tipped and still be used, cant find that info though.

clear as mud????

hope this helps

G3

[Rojodiablo]

Acetone will not leave its home unless it is forced out by pressure or the tank is left lying down. It is not part of the burning process, it only releases the acetylene gas that is stored, in the cells of the filler in the cylinder, When the cylinder is to be refilled it is weighed and acetone is added until the cylinder weighs what is stamped on the cylinder (TW)
I hope it is somewhat clearer now, or I will try another avenue. John

Okay, I think I understand it. If the bottle comes in bone dry, too light, etc. they fill the bottle with X amount of acetone, as specified, then they would add the acetalyne- correct?? Thanks John and G3!! That was the scenario they played out in welding shop a zillion years ago- a cutting torch was on its' side, valve open. A Q&A training thing. But I never got the answer on the acetone inside, just the fact there was acetone, so the gas on the ground might be wet.

[weldgault]

I have been dealing with acetylene for almost 40 years and I don't know the angle you can have the cylinder, just as streight up as possible. You are making the mud a little clearer. John

[Shade Tree Welder]

John, and Ron, I have a question for you. If the acetone in the tank is aspirated, or say the bottle is run dry is the correct way to ask this- if the bottle is run dry, and left open, will the acetone inside evaporate quickly enough to need special accomodation when the bottle is refilled? Or is the acetone and acetalyne mixed at the time of filling, and the acetone is part of the product you burn through the torch? Great post guys, thanks for putting it up. I have never heard an answer to this, my welding teacher a zillion years ago just said" There's acetone in it."

I will also add that the acetylene tank should never be run dry, 0 PSIG on the gauge. You should leave ~5 psi in the tank.

[weldgault]

Any more questions, before it goes to sleep. John

[69 chevy]

Not a question, just a little more acetylene procedure: Oxygen cylinder valves should be either closed or all the way open. Not so for acetylene...only open the valve 1\2 to 1 turn.

[weldgault]

Sorry, I didn't know we had to go that far into the basics. John

[TozziWelding]

And people wonder why I run LP/MAPP gas

[slamdvw]

The way I was taught, open an O2 valve all the way, it's a back seating valve. Was told they'll leak around the stem if not all the way open. Acetylene, only open 1/4 to 1/2 turn, just in case there's a problem, it can be snapped shut in a jiffy.