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Need help with acetylene torch


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  #1  
Old 02-27-2007, 03:28 PM
Ronald E. McClellan Ronald E. McClellan is offline
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Default Need help with acetylene torch

I have some iron bar (2 3/8" X 7/16") that I need to form. I made a form out of 1/4" plate. I have a rosebud head that has about a 12" extension from the handle. Both of my tanks are low , but I was able to get good pencil point flames , so I figured I would use them until the ran out. I was heating the bar for about 5 minutes when the flame would pop off then back on. after a couple of minutes it started to go off like a machine gun. Then the tubing near the handle started to turn red. That tells me that the flame is running back down the tube. I tryed to adjust it , but wasn't able to do so. I was afraid of something bad happening , so I shut it down. It is all old equipment? What is going wrong? HELP! Ron
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Old 02-27-2007, 04:22 PM
Robert Haus Robert Haus is offline
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Default Re: Need help with acetylene torch

Sounds like not enough acetylene for the volume of O2 being delivered...if you suspect your tanks are below the regulator output settings it would be best to have them refilled. What you experienced is a form of flashback...if it flashed back into the hoses and regulators it could have easily exploded. If you have any doubts about the equipment condition, run it by a welding shop and let them look it over...most welding supply stores are very helpful....it is also possible that the tip is part of the trouble...in any case I would not try it again until you have isolated the problem.
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Old 02-27-2007, 04:26 PM
Robert Haus Robert Haus is offline
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Default Re: Need help with acetylene torch

Forgot to mention, a rosebud tip needs more volume to work than the pencil tips...again, check the regulator and tank pressures....most basic welding books will tell you some recommended settings to start off with for using various tips.......and always shut off the O2 at the torch handle BEFORE shutting off the fuel gas...this will help prevent flashback.
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Old 02-27-2007, 04:26 PM
cat d9 cat d9 is offline
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Default Re: Need help with acetylene torch

you are low on gas, get the tanks full and you will be fine.
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Old 02-27-2007, 07:45 PM
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Dustin D Ehli Dustin D Ehli is offline
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Default Re: Need help with acetylene torch

Not related but everyone should have flashback arrestors on the torch head to stop any potential flames from entering the hoses, they are not that expensive.
Dustin
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Old 02-27-2007, 09:18 PM
Franz Franz is offline
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Default Re: Need help with acetylene torch

Rosebud + insufficient suply of acetelene = NOT HAPPENING

You can only withdraw acetelene from a bottle at a certain rate without getting into serious trouble. Your rosebud is overdrawing, and the flame is going out for lack of fuel. Restart with a full tank before you blow something up.
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Old 02-28-2007, 12:18 AM
Andrew Mackey Andrew Mackey is offline
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Exclamation Re: Need help with acetylene torch

For heating purposes, you need to have 35 to 40 PSIG on the Oxygen, and 8 PSIG on the Acetylene. PSIG=Pounds (per)Square Inch-Guage. Pressure is one thing, Volume is another. You want minimums of at least 500 PSI-hi pressure guage - Oxygen, and 50 PSI hi-pressure guage - Acetylene. Any lower than that, and you are asking for trouble, such as you described, especially with a rose bud tip. Innsuffecient gas supply pressure allows the flame to travel back toward the fuel supply, within the torch handle assembly, to the point where the fuel and oxygen mix. This condition is called a 'Back-Flame'. Failure to shut down the FUEL source Immediately, can have serious consequences, including possible torch and tank rupture and explosion. Basicly what happens during a back flame, is that the heat you had at the tip, is now within the interior of the brass torch handle. This enclosure causes the rapid, and extreme build up of heat within the handle assembly, which could literally melt the torch apart within a minute - or less . If you should hear a back fire, and or a strange whistling sound, when using your torch, SHUT IT OFF - IMMEDIATELY !!! Let the handle cool thoroughly, and check both the tip, and the torch head, and make sure the tip is clean, and the gasket, and or O-Rings are not damaged, and that all connections are tight. When using a Rose Bud tip, do not allow the tip of the primary flame to deflect off the work. Deflecting the primary flame causes haet build up at the tip, and can lead to back flame.

Forgive me for asking, but do you know how to properly light and set the flame on your torch? Different tips require different set ups, and flame types, in order to effectively, and effeciently do the work required. If you need a quick tutorial, please advise, and I will pass the info along.

Andrew
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Old 02-28-2007, 02:18 AM
Robert Haus Robert Haus is offline
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Default Re: Need help with acetylene torch

Quote:
Originally Posted by Andrew Mackey View Post
Failure to shut down the FUEL source Immediately, can have serious consequences, including possible torch and tank rupture and explosion. Basicly what happens during a back flame, is that the heat you had at the tip, is now within the interior of the brass torch handle. This enclosure causes the rapid, and extreme build up of heat within the handle assembly, which could literally melt the torch apart within a minute - or less . If you should hear a back fire, and or a strange whistling sound, when using your torch, SHUT IT OFF - IMMEDIATELY !!! Let the handle cool thoroughly, and check both the tip, and the torch head, and make sure the tip is clean, and the gasket, and or O-Rings are not damaged, and that all connections are tight. When using a Rose Bud tip, do not allow the tip of the primary flame to deflect off the work. Deflecting the primary flame causes haet build up at the tip, and can lead to back flame.

Andrew
I agree that shutting down the torch immediately when a flashback/burn back condition results is the only safe course of action.

However (professional welders please correct me if I am wrong) I would think it much safer to shut off the O2 FIRST. The reason being that this will force the fuel to burn outside the torch or will extinguish it immediately. Leaving the O2 on would still allow combustion even after the acetylene was shut off if the parts were hot enough.....don't believe me? Fire up your cutting torch, get a piece of steel glowing hot and press the cutting oxygen lever...then while you are burning through the metal, shut off the fuel and leave the oxy on...it will keep on cutting! The reason being that the oxygen continues to burn (oxydize) the metal. I am not certain that this could ever happen in the confines of a torch handle (I have never let one go long enough to find out) but I've always been told to shut off oxygen before shutting off acetylene.
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Old 02-28-2007, 01:24 PM
Ronald E. McClellan Ronald E. McClellan is offline
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Default Re: Need help with acetylene torch

Thanks to all for the quick responce and helpful advice. I'll be going out today to get fresh tanks. Ron
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Old 03-16-2007, 09:13 PM
gltracajun gltracajun is offline
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Default Re: Need help with acetylene torch

Quote:
Originally Posted by Ronald E. McClellan View Post
I have some iron bar (2 3/8" X 7/16") that I need to form. I made a form out of 1/4" plate. I have a rosebud head that has about a 12" extension from the handle. Both of my tanks are low , but I was able to get good pencil point flames , so I figured I would use them until the ran out. I was heating the bar for about 5 minutes when the flame would pop off then back on. after a couple of minutes it started to go off like a machine gun. Then the tubing near the handle started to turn red. That tells me that the flame is running back down the tube. I tryed to adjust it , but wasn't able to do so. I was afraid of something bad happening , so I shut it down. It is all old equipment? What is going wrong? HELP! Ron
Hello Rod,Your problem is twofold.First off,let me say that I was A welder/pipefitter in and around the Gulf of Mexico for over 35 years.
First off in your haste to heat the metal,you were holding the rosebud tip too close to your work.Plus,with your tanks low,you allowed(because of lower pressure)your gas to back up into the mixing barrel.
Your average pressure on OX should be at least 60 psi and Acet at lest 20 to 30 psi.
The hottest point of your flame is at the very tip of the flame,rule of thumb is farther from the head,not closer.Closer can cause a very dangerous situation.Your torch could blow up like a stick of Dynamite.
Remember,that tanks with low pressure may be fine for cutting with a 00 tip but can spell trouble for use with a rosebud.
Hope that this is of some help. Regards,Gene
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