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Up Topic Welding Industry / General Welding Discussion / Acetylene Bottle Question.
- - By Platinumbased (**) Date 12-22-2010 22:15
Is it proper to use an acetylene bottle all the way down until there is zero pressure on the regulator just like an oxygene bottle?
I was told that the solvents in the bottle can flow into the regulators and mess it up if you do this.  Is this true?  Thanks
Parent - By JLWelding (***) Date 12-23-2010 00:21
If it is laying on its side or not tilted up enough.
Parent - - By texwelder (***) Date 12-23-2010 00:47
jl welding is right i may be wrong but they are supposed to be on at least a 15 or 20 degree angle to keep the liquid acetone from coming up in the neck
Parent - - By 803056 (*****) Date 12-23-2010 02:16
Acetylene tanks are supposed to be in the upright position when in use. It is recommended to leave some pressure in the tank to minimize the potential for drawing the acetone out along with the acetylene.

The maximum withdraw rate is 1/15th the capacity of the cylinder when used continuously and only 1/10th the cylinder capacity when used intermittently.

I may be mistaken, but I believe John Wright gave us a link several months ago connecting us to OSHA's site with the new limitations noted above.

Feel free to ignor the information provided. I'm sure many welders do, but the penalties are rather stiff should the kind folks from OSHA get involved.

Best regards - Al
Parent - - By texwelder (***) Date 12-23-2010 02:36
OSHA is another goverment run operation targeted towards controling americans i mean we need safety but thet are pushing it to the limits
Parent - - By 99205 (***) Date 12-23-2010 03:08
Always better to be safe.  Death is the other alternative.  Almost all OSHA reg's are the direct result of a serious injury or death.
Parent - - By NMWELDING (**) Date 12-23-2010 04:14
I think he is asking if a bottle can be ran empty,down to zero, in the upright position. I run mine empty in the upright position all the time,no problems.
Parent - By texwelder (***) Date 12-24-2010 20:21
thats right as long as its standing up
Parent - - By 803056 (*****) Date 12-23-2010 16:35
Death is permanent and it's Darwin's way of keeping the gene pool from regressing.

There is no cure for stupidity and with or without OSHA, Darwin will prevail. 

Did you attend one of those public schools in Texas?

It's been nice knowing you Tex. What address should I use to send your wife my card of condolence?

As I used to say to my Ironworker buddies when I saw them do something stupid and unsafe, “Can I have those new boots you're wearing when we bury you?”

That was usually enough to get their attention.

Best regards - Al
Parent - By 803056 (*****) Date 12-23-2010 21:09
Beat me with a stick, it was our good friend Dave Boyer that gave us the inside scoop on the latest and the greatest regarding the withdraw rate of acetylene.  Here's Dave's comments from his past post:

"The following was posted on another forum by an industrial safety guy, as the topic had come up there:

For those interested in Acetylene draw rates.
Just got an "OSHA Quicktakes" today of interest.
Mentions that the rules for Acetylene had been changed and became final. Mentions that the new rule is based on the now out of date CGA G-1 rule of 2003. Current CGA G-1 is 2009. At any rate the 1966 rule called for 1/7th of tank capacity draw rate. The 2003 rule calls for 1/10th draw for intermittant use, and 1/15th draw rate for continuous use.
Interesting.
Reference 29CFR1910.102, 1910.102(a), and 1910.253

Pretty hard to use a rosebud without exceding these draw rates. Comments?"

Thanks for the information Dave.

Merry Christmas everyone.

Best regards - Al
Parent - - By raftergwelding (*****) Date 12-30-2010 07:34
I run my bottles standing up and have run them down to 0 from day 1 and no problems. No you cant have my boots cuz i aint done with them yet as for the card take it to the out house with ya they are always out of paper
Parent - By DaveBoyer (*****) Date 12-31-2010 03:00
When We were building Our first solar water heating pannel there was a lot of copper sheet to be soft soldered to the copper water pipes. The Bernz O Matic propane torch just wasn't enough. I set up the oxy acetylene torch with a small tip & 3 PSIG. The acetylene cylinder pressure didn't register, but Pop soldered up the whole thing, and the gas just kept coming out. At low pressure and delivery , there was a lot more gas in that cylinder than I thought. Perhaps it was oxy acetone acetylene soldering, but it worked.
Parent - By DaveBoyer (*****) Date 12-23-2010 04:12
When You look up how many tanks You are supposed to manifold together to feed a medium sized rosebud, propane or propalene start to sound reall good.
- - By thetraininglink (*) Date 12-23-2010 16:46
The standard for acetylene use is no less than 40 psi cylinder pressure for any use, and the maximum withdrawl rate for aceylene is 1/7 of the existing cylinder volume per hour.  So a 140 cubic ft acetylene bottle will only give up 20 cfh when it's full, and only 4 cfh when it has 50 psi cylinder pressure.  That will feed a small welding tip, but not cutting tips and certainly not rose buds which require anywhere from 20 cfh to 150 cfh!  Acetylene cylinders must be used in the upright position, and if ever on their side must stand upright for 8 hours before use.  This is all to prevent acetone from withdrawing from the cylinder (damaging regulators and hoses) and prevent tip starvation which will cause the tip to overheat and create backflashes.  I suggest you research CGA standards.
Parent - - By rlitman (***) Date 12-23-2010 21:21
I don't know where people come up with this, but the 1/7th rule is based on the total cylinder capacity, and NOT the remaining contents.
If it were based on how much remains, you would never be able to empty the cylinder.  Look up "Zeno's Paradox".
Parent - By Tommyjoking (****) Date 12-25-2010 05:54 Edited 12-25-2010 05:59
I reckon that is why the big boy rosebud I was using started to spit sparks and burning liquid in the middle of my bending the other day.  The use the little acetylene tanks instead of the large ones I am use to.   I am a big fan of flame arrestors too...they are not using any.   They also lay down their bottles (about 20 degrees) on the portable rig.  I am trying to convince him to run larger bottles for cost savings PLUS if I have to go out and buildup shear blades or preheat some buckets or something the little bottles will not run the rosebud I will need for very long.  Course I have already told him about the issues with laying the bottles down.  Fighting the we have always done it this way thing.
- - By Platinumbased (**) Date 12-26-2010 20:41
Yes, I meant running them completly dry in the upright position.  The guy I work with runs them right down to zero and cranks up the regulator to the max in order to get every last drop of acetylene out of it.  I stated that this was not proper procedure as the acetone could get drawn into the regulators.  He ignored me and just kept cutting.
Parent - - By DaveBoyer (*****) Date 12-27-2010 02:58
For what it might be worth, here is a picture showing the inside of an acetylene cylinder:

http://www.farwestforge.com/Forum/bsgview.php?photo=136&cat=T&by=
Parent - - By bozaktwo1 (***) Date 12-28-2010 18:31
Awesome pictures, love all the old stuff.
Parent - - By 803056 (*****) Date 12-28-2010 20:13
I second that.

Al
Parent - - By Tommyjoking (****) Date 12-31-2010 17:26
Speaking of propylene .....how many of you have experience with it?   Do you need to run an injector torch to use it or can you really get by with just running different tips?  Will it cut well?    I am fixing to sign a deal with a supplier and I am thinking on going with propylene instead of acetylene....but I got zero experience with it and I don't want to invest in new torch stuff unless it is more cost effective.
Parent - By Northweldor (***) Date 12-31-2010 18:34
Chet Guilford's shop did an interesting comparison some years ago.

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=23268;hl=Propylene
Parent - By Lawrence (*****) Date 12-31-2010 18:39
Tommy,

In day to day hand cutting, for me there is not much difference at all between acetylene and propylene when the rubber meets the road.

If your rig is totally personal, you might want to go with the two piece "high speed" tips..  They are a bit more fragile and expensive, but if your not sharing the torch with anybody that's usually not a problem.. I like the two piece tips far better because you don't have to pay any attention to where the pre-heat holes are aligned.

I don't see any reason to do more than get a set of tips that are designed for the propylene..  We run it with both check valves and flashback arrestors and have no issues with flow restriction at fuel gas pressures as low as 3psi.  It works good.
Parent - - By welderbrent (*****) Date 01-01-2011 18:14
Your welding supply will tell you that the change will require different fuel gas hose.  According to the manufacturers they are correct.  BUT, I know several people who have kept running their Acey hoses and have had no problems.  I believe all of mine got changed out when we changed to Propylene. 

One supplier even told me I needed different gauges.  Didn't do that.  They need replacing every so often from abuse and old age anyway.  Never had one just go bad on me that could be attributed to the fuel gas.

The main difference is the tips.  Definitely need to change them to the two part tips to run propylene.  Most all the fuel gases except Acet use the two part tips, MAPP, Propane, Nat Gas, & Propylene (Praxair calls theirs StarGas I believe).

The torch body and mixing tube assymbly is the same.

Have a Great Day,  Brent
Parent - - By Lawrence (*****) Date 01-01-2011 21:23
Brent

That is a very good point that I neglected to think of.

There are several grades of fuel gas hoses.. Some can accomodate multiple fuel gasses and some cannot.

It would be VERY WISE to make sure your fuel gas hoses are compliant with the fuel you are using... 

I believe the consern is long term degridation of the hoses when the wrong fuel gas is used... So the danger is a sneeky one.  Hoses are not that expensive, so it's better to change them out right away rather than risk forgetting about it and having what might be a pretty big issue later.  Nobody wants to be around a failed fuel gas line.
Parent - - By Tommyjoking (****) Date 01-01-2011 22:40 Edited 01-01-2011 22:44
Alright yall have gave me some good answers...couple more questions.    Well I being told you do not have the draw vs bottle capacity issues like you do with acetylene...at least from the salesman.  I do not mean to sound picky or particular about it all but..... In Chet's post referenced above he mentions that Acetylene still gets loaded on the truck because it is more versatile in unknown work situations.

How so, does it have some advantage over propylene (or propane)?   I am looking at a lot of work that will require big rosebuds for long periods and weld scarfing/gouging both portable and in shop.  I want to go with one fuel gas for all the work.  It seems that propylene will be more cost effective as long as it has the capability.
Parent - By Superflux (****) Date 01-02-2011 00:01
For bucket preheating and other large projects, nothing beats a 20# or 40# propane bottle with a weed burner. Depending on the size of material, sometimes its is time and cost efficient to preheat say a piece of 3/4" plate with the weed burner prior to localized heating with rosebud for bending. Done this many a time when relining AR plate onto buckets.
If you have drawn acetone into a hose (spitting liquid and  little sparkelies), it will rot the hose internally. Look inside the hose and if there is gooey, tar and or black residue, it is time to replace the hose.
Parent - By DaveBoyer (*****) Date 01-03-2011 04:25 Edited 01-03-2011 04:34
Tommy, You can draw it hard untill the bottle gets so cold from the liquid boiling off that the pressure drops below what You need. In this respect, propalene is about the same as propane.

The break down as I understand it, propane is the cheapest bottled fuel gas, but provides the lowest flame temperature.

Propalene is more expensive than propane, but cheaper than acetylene. Propalene or propane are safer than acetylene, not nearly as shock sensitive, and have no pressure limitations, could in theory be used up to tank pressure. Due to this propalene and propane can give more BTU's altho at a lower temperature than acetylene. Propalene has quite a bit higher flame temperature than propane, but lower than acetylene. Tip to work distance in propalene cutting is not as critical as with acetylene, can be quite a bit greater without affecting performance.

Acetylene has the highest flame temperature, but pressure, delivery & safety limitations as You are aware of. It is the most expensive, but everybody is familliar with it.
Parent - - By Northweldor (***) Date 01-01-2011 23:34
In addition to what Lawrence mentions above, here is some info on "T-grade" hose ( close to $3 a foot, but good for any gas).

http://weldingdesign.com/processes/news/wdf_45963/
Parent - - By Tommyjoking (****) Date 01-02-2011 03:44
John if I got a lot of preheat like shear blades or something and enough of it I usually do grab a propane tank.  It sure beats running your oxy and fuel bottle down.  You hit the nail on the head, I am talking about heavy equip work.

DID not mean to hijack this thread but...seems like the place to do it.   The only disadvantage I can research out is I cannot weld with it due to lack of CO2 produced......  I am assuming I can still braze with it fine as my flux is doing my shielding...correct?  I also hear that the torch tip must be a little higher for cutting (get the cone away from the plate).   If that is the only disadvantage, I do not know why anyone is still using acetylene other then tradition.  Anything that will keep more green in my pocket I am all for.
Parent - - By Joseph P. Kane (****) Date 01-02-2011 04:30
Tommyjoking

You cannot weld with it, because it does not get the base metal hot enough, not because of CO2.
Parent - By DaveBoyer (*****) Date 01-03-2011 04:14
Joe, I respectfully disagree. The problem is that there is not the reducing atmosphere in the secondary flame that You [only] get with acetylene.
Parent - - By Superflux (****) Date 01-02-2011 09:18
Yes, I too was drawing upon "Heavy Equipment" work experience. Dragline buckets in excess of 70 yard capacity (up to 125 yard Esco), Shovel buckets in 20 to 45 yard and the smallest dozer I've ever worked on was a Caterpillar D8.
Oxyacetylene flame is the Hottest chemical flame in commercial use...anything of higher temps are electrically generated... i.e. plasma.
Brazing and cutting can be accomplished with other (than acetylene) fuel gases. For Oxy fuel gas welding, I have no personal experience other than with Acetylene, and have welded pipe up to 4" NPS with this process.
For cutting operations, technique is always the same and cheating (increasing pressures and volume through an undersized tip) will only produce substandard results.

I am all about saving money! Labor is typically the highest expense, with consumables being the runner-up. The basic material price is usually figured in accurately by the Engineers and Purchasing Agents. Excessively high labor costs often comes from improper consumable application.
And finally, CO2 (and H2O) is a byproduct of most flames. Welding of ferrous material with a flame (not brazing) is dependent upon having a hot, concentrated heat source that can only be efficiently supplied by oxy-acetylene or hydrogen to my limited knowledge.
On a side note, I was told by a colleague that propane MUST be used to preheat because the oxyacetylene flame of a rosebud would introduce carbon into the base metal...I silently walked away, since it did not affect any current decision on the project at hand.
Parent - By Tommyjoking (****) Date 01-02-2011 17:49
"On a side note, I was told by a colleague that propane MUST be used to preheat because the oxyacetylene flame of a rosebud would introduce carbon into the base metal...I silently walked away, since it did not affect any current decision on the project at hand."

Wow I have been doing it wrong all these years apparently!  LOL      Those are some huge buckets..big hammers!   I just need it for typical trackhoe, backhoe and dozer work.    The only thing I can think of I would want to oxy fuel weld would be cast iron...that comes along rare enough that if they really want it they can pay for small acetylene bottle.
Up Topic Welding Industry / General Welding Discussion / Acetylene Bottle Question.

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