Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Technical Discussions / is Acetylene safe ??
- - By alexp Date 11-07-2004 11:47
Hello All,
A question from someone new to anything beyond a tank of propane:

I purchased a Prestolite acetylene/air torch for hobby silver soldering ( steam engine piping ) and a small MC bottle of gas.

I started internet searching about why acetylene is dissolved in acetone and clay, etc. and found enough information about the gas becoming shock sensitive above 25 psi and its ability to self polymerize into an explosive inside the bottle that I am ready to bury the thing in the back yard until I can return it !

Whats the practical story ? How can the gas be pressurized to several hundred psi in the neck of the tank and regulator without danger of an explosion ? If I set the tank down hard some time, can I potenially initiate an internal polymerization reaction ( tank heating and vibrating ) leading to an explosion ? Are all tanks safe - can old ones have defects that can cause suseptibility problems ???

Is it 100% save to keep a tank of acetylene at one's home ? I am not concerned with leakage - the tank and fittings are tight - its the bottle going into self destruct mode that has me nuts !

As you can see, in my quest for information, I have transitioned from excitement about getting a torch perfect for my application to total paranoia.

Assistance Please !

Thanks,
Ap
Parent - - By pipewelder_1999 (****) Date 11-07-2004 13:19
Properly handled it is very safe. I have seen a bottle dropped onto concrete floors, regulators set at 50 psi, and various other unrecommended practices. I think that as long as you follow the recommended practices for handling this, it will be fine.

Take the red ryder bb gun. A very safe item when properlyy handled, yet the cpsc has had to take action because of potential accidents that result from non-standard use. Dont fire up you BBQ with this :)

Gerald Austin
Parent - - By alexp Date 11-07-2004 19:52
Hi Gerald,

Thanks and I am sure everything you said is true.
But, I am spooked at the thought of a potential disaster.

The bottle goes back tomorrow and I go back to MAPP.
Wanna buy a Prestolite torch for half price ?

Best,
Ap
Parent - By pipewelder_1999 (****) Date 11-07-2004 20:29
Mapp is pretty goodstuff. If you haven't used the acetylene too much, you not notice much difference if brazing

Don't need a torch. Try Ebay!

Havea good day

Gerald Austin
Parent - - By supermechanic (**) Date 11-07-2004 23:08
An inherently dangerous product would have been taken off of the market years ago. Don't let Chicknen Little convince you that the sky is falling.
Parent - - By alexp Date 11-08-2004 00:12
Hello SuperMech,

I know, that is the paradox : I read that acetylene is a gas that can mutate into something as explosive as dynamite - on the other hand, it is used in commercial apps as frequently as weekenders with propane barbeque grills with no mishaps....

But, there is evidently a potential instability with acetylene (perhaps slight) not manifest in other gasses even - hydrogen.

Ap
Parent - - By hankj (*) Date 11-08-2004 02:23
Acetylene stored and used properly is no more dangerous that a motor vehicle stored and used properly! As you have learned, acetylene is disolved in a filler saturated with acetone. It is completely safe as long as you: 1) store it upright. If you lay it on its side for some reason, let it stand upright for at least 30 minutes before using it. 2) Do not adjust regulator pressures to greater than 15 psig. Acetylene becomes unstable at this pressure. For your purposes, this will never occur. You will rarely, if ever, use more than 2 psig regulator pressure. 3) Do not use a cylinder whose pressure is less than 25 psig. At this pressure, it is possible to draw liquid acetone from the cylinder, which can destroy the regulator and result in liquid acetone being allowed to enter the torch.

Like driving that motor vehicle, you just need to pay attention!

Hank
Parent - - By RonG (****) Date 11-08-2004 12:54
Hey AP, just curious; Do you have electric power in your home.

Maybe you did the right thing returning the Acetylene bottle if you are that paranoid.

Safety is relative and Perception is reality. Just amagine what might of happened if you accidently dropped your lit torch.

About Hydrogen, have you ever heard of any one developing a Acetylene Bomb?
Parent - - By alexp Date 11-08-2004 22:11
Hi Ron,

With sufficient energy, two hydrogen atoms can be 'fused' into one helium with a consequent release of major heat energy and radiation - unrelated to its propensity to combine with oxygen (burn).

My issue with acetylene is the somewhat uncontrolled conversion of the highly flamable but stable gas into an explosive form via polymerization initiated by heat or shock. And, perhaps contamination can act as a cataylst and make some bottles more sensitive than others....

I like being in control, not sure that is always the case with this particular gas....

Best,
Ap
Parent - By pipewelder_1999 (****) Date 11-08-2004 23:21
I like it :) .

I've been around this stuff for years. I have a 20 Ft^3 argon bottle that I have have my children stay away from. I had a little 80 amp welder that I built a few home projects with and was nervous for 12 hours after thinking a spark had somehow travelled through the air and kindled all afternoon waiting to burn my house down.

There are many things I have dealt with on a daily basis that I don't want anywhere near my house.
Parent - By RonG (****) Date 11-09-2004 12:57
AP, Not disagreeing with you, just not not understanding how some one who seems to be so enlighten managed to bring home a bottle of Acetylene and then discover its potential.

In fact I agree that Acetylene has no buisness in ones residence but not because of its exposive potential. I have electricty in my house but I don't use my disc grinder or welding machine in it.

You read some information and you and got so paranoid you failed to complete your research. Do you really think that all those folks using and handling Acetylene are relying on just dumb luck every day?

Or is it possible that at some time some smart guy or girl (maybe as inteligent you) came up with some ideas to make it safe for the rest of us dummies.

Just think if them poor miners way back when knew they were carring Acetylene bombs around on there heads they may have invented electric lights a lot sooner.

So are you going to find another hobbie or safer gas? By the way if you really wanted to you could bury the bottle in the back yard and run a soft hose to where you work. It won't explode in a soft hose.
Parent - - By CHGuilford (****) Date 11-09-2004 17:37
alexp,
As has been mentioned, acetylene has been use for a long time, with industrial use going back to the 1800's. It needs to be respected but does not need to be feared...no different than the can of gasoline many of us have to fuel up our lawn mowers.

If you are using equipment and accessories made for acetylene use there should be no problem. Acetylene in the tank is dissolved into acetone, which allows the pressure to be safely increased. There is a porous material that fills the inside tank space that absorbs the acetone and acetylene. As the acetylene is drawn off, the volume of gaseous acetylene is very limited, so there is not much that can detonate. The regulator limits the possibility of mechanical shock or heat affecting the acetylene while it is pressurized over 15 PSI. When it is below 15 PSI, acetylene is not prone to detonation.

Naturally, you need to exercise due care and caution when cutting, sparks can go into areas you wouldn't notice. Allowing the unignited torch gases to flow for a bit could cause a surprise if they collect somewhere and receive a spark. Failure to use flow check valves and flashback arrestors could allow you to see what happens when a hose blows up and could damage/destroy your regulators.
But again, use due care and caution and you won't have any problems. After all, you wouldn't pour gasoline all over your garage floor with the doors closed and then start grinding, would you?
Use of acetylene torches is not the gamble you seem to think it is. maybe you could attend a training course to ease your fears?

Chet Guilford
Parent - - By alexp Date 11-10-2004 10:03
Hello Chet and All,
I got a bit obsessed with the safety issues related this gas. My fear was that the acetylene would on its own spontaneously start to decompose, overheat, blow the meltout vents and fill (momentalriy) the garage with gas. An overdose of MSDS sheets can themselves, have adverse effects after a while...

I think it better to not store this gas in the garage - I am going to be getting a small backyard shed - that will be its residence.

I keep the BBQ 20 lb Propane cylinder outside .

The model steam boiler has a 60PSI safety valve (verfied), and it is recommended (and I've done) a 120 PSI hydrostatic test
periodically.....

Best,
AlexP

Parent - By pipewelder_1999 (****) Date 11-10-2004 11:29
You have any pics. I'd like to see what you build.

GA
Parent - - By pipewelder_1999 (****) Date 11-09-2004 14:13
One thing to consider is the relative safety of acetylene compared to say "Steam Engines".

:) Have a good day

Gerald
Parent - - By chaikwa (*) Date 11-10-2004 00:19
I wonder if he realizes that the average 20lb propane bottle, such as those used on a BBQ grill, is the explosive equivilent to 66 sticks of dynamite? And from my, ahem, 'experiments' in the past, most often the relief valve doesn't allow for adequate venting of a propane tank that's exposed to prolonged heating or direct flame impingment.

chaikwa.
Parent - - By RonG (****) Date 11-10-2004 13:02
Ap, Now that your paranoia is quelled (snicker snicker) I will attempt to undo it.

On occasions not all the Acetylene coming out of the torch gets consumed, if you working on a container (I learned this by welding on a large truck muffler) some gas may get trapped in the container, if it finds a source of ignition it can ruin you work, make big noise, remove all the dust a trash from the over head rafters and what have you.

Not nearly as dangerous using you torch set (no Oxygen mix).
Parent - - By alexp Date 11-14-2004 10:38
an interesting, if lengthy, article ..

www.eiga.org/pdf/Doc%20123%2004%20E.pdf



Best,
Ap
Parent - - By leon phelps (**) Date 11-17-2004 01:40
I remember a website describing a bunch of guys in TX that were having a contest to see how long a new Weber grill could be totally obliviated. I think the record was 8 seconds. The Federales and the local FD made the group take the pics and info off of the web. Oh the good old days before soccer moms understood science and politics.

I do remember them using acetylene and another gas blend.

I got a look at the document. I was having trouble understanding the warnings in metric.
Parent - - By alexp Date 11-18-2004 01:18
I remember a website describing a bunch of guys in TX that were having a contest to see how long a new Weber grill could be totally obliviated....

That was a university Physics class spring picnic. They soaked the charcoal in liquid Oxygen and lit it from a distance. The charcoal ignited into a huge fireball- the remnants of the grill were reduced to a molten blob in a few seconds. I think they required an alternative to cook the hamburgers..

- Ap
Parent - By billvanderhoof (****) Date 11-18-2004 08:25
I have heard of a blasting explosive which consisted of coal dust soaked with liquid oxygen. Surely charcoal would work too. If they had had a blasting cap to get things going they could have really made that bbq disappear.

All fire gags rigged by professional pyrotechnists, do not try this at home.

Bill
Parent - - By caweldtech.com Date 11-17-2004 16:49
Greetings,
One more bit of acetylene information. Never use copper tubing to convey acetylene. The acetylene reacts with copper to form “copper acetylide”, an unstable compound, which can explode spontaneously.

Dave
Parent - - By pipewelder_1999 (****) Date 11-17-2004 16:59
BUt no problem with copper alloys?
Parent - - By JTMcC (***) Date 11-17-2004 18:53
Acytelenophobia? Is this a new one?

Look up a few statistics, like the number of people killed/injured in car wrecks per year. And the number killed/injured in bathtubs. And then the number killed/injured by acytelene accidents.

JTMcC.
Parent - - By RonG (****) Date 11-17-2004 20:54
All in all its been an interesting & enlighting string to say the least. Because of it, I learn a new term.

"DEFLAGRATION": "to burn rapidly with intense heat and sparks being given off"

Now I know I seen that happen on occasion so from now on if I see it going on I can say: Hey thats a bunch of DEFLAGRATING.

But one things for sure. If I ever catch my Acetylene POLYMERATING, I'm going to fix it real good.

There are plenty of dangerous things around us if we allow them to become dangerous. But the most dangerous thing around us is our selfs when we fail to properly handle any thing as innocent as half filled pale of water and unattended child (toddler) or an UNLOADED gun.


Parent - - By CHGuilford (****) Date 11-18-2004 19:51
Deflagration! Is that what happens when you combine chili and beer in a 'closed container'?
Chet

Parent - By RonG (****) Date 11-18-2004 22:01
Phewwweee! Add some boiled eggs and you got Polymeration. Now theres and explosive combination. Guaranteed to make every one run for there life.
Parent - - By pipewelder_1999 (****) Date 11-17-2004 21:02
How many tube welders do you think break their ankles per year skateboarding?

We're only passing through, might as well live while we are here. Worst case, We Die! Best Case, We Die. It's just a matter of making it a "best case senario" .

We're all gonna get something from excess computer use .
Have a good day

Gerald

Parent - - By RonG (****) Date 11-17-2004 21:06
I already have, my clicking finger aches all the time.

I just snapped to that Skate boarding. Who says welders are no fun. Are we going to get to see this on AFV?
Parent - - By pipewelder_1999 (****) Date 11-17-2004 23:01
Luckily there were no cameras there. I actually skateboard a little. http://www.weldinginspectionsvcs.com/KidsSkateboardPics/Collierville8Nov03/index.html

Did it when I was a kid, stopped when puberty took over, and started back a little less than 2 years ago (not long after puberty ended) when my son expressed an interest in it and and I stepped back on one.

I actually have more skateboarding pics on my website than I do welding pictures.

About half the people in the ER I went to in Nashville thought it was neat that a 40 year old 240lb guy skated. The other half probably shook their heads, went home, sat the kids in front of the Nintendo, and had a nice quiet day.

Not only do I skate. I have been known to lay an acetylene bottle on it side and then not stand it up for the correct time before using.Usually because by the time I got the bottle to where I was going I was wound up from dodging objects as I rolled the bottle on its side across the grating.

So there it is, a pattern of doing unsafe things! Luckily I grew out of the second one.

GA
Parent - By SLowChild (*) Date 12-01-2004 05:08
If that scares you imagine being in a 4ft square room turning on the manifold system all alone with 6-8 bottles being stored and 3 being cranked on listening to the water bubble in the back flash. Everytime flipping the sealed light switch just rememinds you of what could happen.
Parent - - By Welder 42 (*) Date 12-03-2004 14:06
Alex,
It is safe to have the bottle in your shop I wouldnt want it in my kitchen but it is safe, I recommend that you get someone who knows what they are doing and let them properly train you on how to use htis equipt.
Do not EVER go over 15 psi line pressure! You will learn the difference between line pressure and regulator pressure.

Most jobs I stay between 4 psi and 9 psi of Acetylene.
Just get proper training before playing with this stuff and you will be more than comfortable with it.
Parent - By Mike W (**) Date 12-05-2004 10:18
I have had cylinders of oxy/act in my garage for the last 30 years and I am still here.
Up Topic Welding Industry / Technical Discussions / is Acetylene safe ??

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill