tab112983 Posted April 4, 2012 Share Posted April 4, 2012 Hello, I made the standard one brick forge for hardening some small blades and I am using an acetylene torch to heat it it. I have a metal heating tip on the torch and have it situated about 5 inches off of the opening of the hole. I make the inner flame about an inch long. As the soft fire brick begins to heat up all of a sudden the torch starts popping like a pack of lady fingers and I have to shut it off. What am I doing wrong? Quote Link to comment Share on other sites More sharing options...
781 Posted April 4, 2012 Share Posted April 4, 2012 Ussually it is dirty tips causing the gas to mix too early Quote Link to comment Share on other sites More sharing options...
pkrankow Posted April 4, 2012 Share Posted April 4, 2012 Usually a 1-brick forge can run on a propane plumber's torch. Why use acetylene? Phil Quote Link to comment Share on other sites More sharing options...
Sask Mark Posted April 4, 2012 Share Posted April 4, 2012 Is your acetylene pressure wrong? Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted April 4, 2012 Share Posted April 4, 2012 When I had popping noises when welding with O/A it was from the incorrect tip size. I am not sure why you are getting this but think it is related. when you push the heat into a small confined area the air fuel ratio is off. May keep in mind that O/ burs wayyyyyy hotter than gasser or solid fuel forge. for small blades keep and eye on the steel color so it does not overheat..Which may be hard on the eyes unless you wear proper protection. Quote Link to comment Share on other sites More sharing options...
doc Posted April 4, 2012 Share Posted April 4, 2012 The problem you are having is most likely caused by your tip overheating. With Oxy/ acetylene popping can be caused while welding simply by holding the torch tip at the wrong angle which causes it to overheat. A dirty tip or wrong fuel pressure mixture as mentioned above can be the causes but confining a tip in a small furnace as you describe is most likely causing the overheating of the tip due to back pressure and reflected heat at the tip. The back pressure is holding the mixture back into the tip and the overheating of the tip is forcing combustion inside the heat tube. If you don't have check valves on your regulators or torches this can definitely be a serious situation. Remember you're playing with acetylene an inherently unstable gas unlike propane. Be careful and find an alternative method to heat your furnace. Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 4, 2012 Share Posted April 4, 2012 Your not running enough acetylene pressure. You didn't say what cylinder size you are using. Acetylene, unlike most other idustrial gasses, is stored in a acytone solution. You know that you are drawing more than the cylinder can handle (draw rate is 1/7 the cylinders volume per hour) when the flame turns white. You may also notice a black substance in the torch. This condition is dangerous and can ruin your regulator and torch. The other thing is starvation, turn up your pressure, since you didn't say what tip you are using there is now way to say for sure. Call your local welding supplier with the tip/tank size for proper setting or even if they can be used together. You can also do a search on Victor Cutting Torches in Thermodynes website and also Smith Torches website. They have good training materials. I almost forgot, do not turn your acytelene pressure past 15psi (ac regs have go red at this point.) Acetylene is unstable past 15 psi and can self combust, this is why it kept in the acetone. I have successfully used acetylene for hardening small blades. I used a firebrick box for a while but now have a stand that hovers the flame over the brick. I have more control over how much heat by moving the blade freely up and down and lenghtwise freely. Usually anything past 6" becomes and issue. Quote Link to comment Share on other sites More sharing options...
SmoothBore Posted April 4, 2012 Share Posted April 4, 2012 I have NEVER encountered a situation where it was necessary to run the Acetylene over 6 PSI Quote Link to comment Share on other sites More sharing options...
Sask Mark Posted April 4, 2012 Share Posted April 4, 2012 When I repaired my large anvil we did the pre-heat with a rosebud tip. I encountered the snapping/popping sound when the acetylene tank was almost empty. We changed the tanks and the problem went away. Quote Link to comment Share on other sites More sharing options...
Dodge Posted April 4, 2012 Share Posted April 4, 2012 The problem you are having is most likely caused by your tip overheating. With Oxy/ acetylene popping can be caused while welding simply by holding the torch tip at the wrong angle which causes it to overheat. A dirty tip or wrong fuel pressure mixture as mentioned above can be the causes but confining a tip in a small furnace as you describe is most likely causing the overheating of the tip due to back pressure and reflected heat at the tip. The back pressure is holding the mixture back into the tip and the overheating of the tip is forcing combustion inside the heat tube. If you don't have check valves on your regulators or torches this can definitely be a serious situation. Remember you're playing with acetylene an inherently unstable gas unlike propane. Be careful and find an alternative method to heat your furnace. I'm in total agreement here. I assume, by "heating tip", the OP is using a small(?) rose bud. A rose bud can over heat just using it too close to the work. I can certainly see it overheating in the confines of a forge. I was a production welder in my past life and we used rose buds almost daily for pre-heating and I have seen them actually melt from within because an inexperienced user didn't shut the torch off soon enough after it started popping. Doc is spot on. The tip gets so hot, the gas ignites inside the torch. BAD JUJU!!! Also, as mentioned above, acetylene is way over kill. I can quite imagine that if the torch did not melt down, the brick soon would :o Quote Link to comment Share on other sites More sharing options...
tab112983 Posted April 5, 2012 Author Share Posted April 5, 2012 Thanks all I was running acetylene because it was what an author of a book I was reading was using. I switched over to propane and after about ten minutes my peice got non magnetic so I quenched it in oil. It looked all kosher so I asume i got a nice heat treat. I think ill do the same with some scrap and have it Rockwell tested just to make sure. Thanks again! Ty Quote Link to comment Share on other sites More sharing options...
Ten Hammers Posted April 5, 2012 Share Posted April 5, 2012 Good thread. Scott did the summary. Just because an author says something does not mean it is the thing to do. Fortunately you live to type again. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted April 5, 2012 Share Posted April 5, 2012 Thanks all I was running acetylene because it was what an author of a book I was reading was using. I switched over to propane and after about ten minutes my peice got non magnetic so I quenched it in oil. It looked all kosher so I asume i got a nice heat treat. I think ill do the same with some scrap and have it Rockwell tested just to make sure. Thanks again! Ty File test? Check for subjective hardness. Phil Quote Link to comment Share on other sites More sharing options...
tab112983 Posted April 5, 2012 Author Share Posted April 5, 2012 Phil, how would you do a file test? Quote Link to comment Share on other sites More sharing options...
pkrankow Posted April 5, 2012 Share Posted April 5, 2012 Take a good file and see how well it cuts into the hardened steel. If the steel is well hardened the file will skate instead of cutting. Phil Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted April 6, 2012 Share Posted April 6, 2012 You changed to propane and had no problems? Did you change your tips? If not there's your problem. Propane and acetylene tips are not interchangable. I would always rather talk to someone face to face when they are having problems like this. Only been in the welding supply buisness about 17 years and seen a lot of crazy stuff. It hadn't occured to me that you would be using the wrong tip, if that's what it was. Quote Link to comment Share on other sites More sharing options...
tab112983 Posted April 6, 2012 Author Share Posted April 6, 2012 No my propane setup is a different torch Quote Link to comment Share on other sites More sharing options...
IRON FIST RICH Posted April 7, 2012 Share Posted April 7, 2012 The problem you are having is most likely caused by your tip overheating. With Oxy/ acetylene popping can be caused while welding simply by holding the torch tip at the wrong angle which causes it to overheat. A dirty tip or wrong fuel pressure mixture as mentioned above can be the causes but confining a tip in a small furnace as you describe is most likely causing the overheating of the tip due to back pressure and reflected heat at the tip. The back pressure is holding the mixture back into the tip and the overheating of the tip is forcing combustion inside the heat tube. If you don't have check valves on your regulators or torches this can definitely be a serious situation. Remember you're playing with acetylene an inherently unstable gas unlike propane. Be careful and find an alternative method to heat your furnace. I think this is the right answer Quote Link to comment Share on other sites More sharing options...
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