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I was welding with a Smith MW202 tip without problems. When I shut off the oxygen the flame went out. I really don't think it burned back into the tip, it just went out. I turned off the gas and put it away for the night. I have never had this happen before. I just swapped out bottles the other day, so they are full. First question, does anyone know why this would happen or had this experience?Next, Smith is odd compared to the other manufacturers, in that they list 10 PSI for both oxy and acetylene for the all their welding tips.That makes no sense to me. I called them about this and they said "Yeah, that's what we recommend". Seems like too much pressure. Second question, why does everyone else list about 3-4 psi for an equivalent tip and Smith says 10 psi?Thanks, Tony
Reply:Originally Posted by El GrecoI was welding with a Smith MW202 tip without problems. When I shut off the oxygen the flame went out. I really don't think it burned back into the tip, it just went out. I turned off the gas and put it away for the night. I have never had this happen before. I just swapped out bottles the other day, so they are full. First question, does anyone know why this would happen or had this experience?Next, Smith is odd compared to the other manufacturers, in that they list 10 PSI for both oxy and acetylene for the all their welding tips.That makes no sense to me. I called them about this and they said "Yeah, that's what we recommend". Seems like too much pressure. Second question, why does everyone else list about 3-4 psi for an equivalent tip and Smith says 10 psi?Thanks, Tony
Reply:makoman1860,Thanks for your reply. So what your saying is to I had the torch knobs open too much for that tip. I never thought about that possibility. I will try reducing the flame and see how it works. I usually use 205 - 209 size tips and don't experience the problem. Smith used to list turning fuel off first, looks like they recently changed their literature on their web site. I have always shut oxygen off first. I have had Victor and Harris torches and I also realize that 10 psi is overkill for a MW202 sized tip, but for some reason that is what Smith pushes for their tips. If there is no reason to run a Smith in particular, that high, I am turning the pressures down.Tony
Reply:You control what the torch gets with it's feed valves. The regulator maintains the pressure released to the torch from the bottles. I have a Smith, never used it, can't get tips for it around here. You always want more than what you need going to your torch. I run my Victors and Harris rig at 10 and 40, cutting and welding. Have been for 40 years with nary a problem. Been that way in every shop I have ever been in.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:I do not know if you have ever created a chamber full of pure acetylene or not. However if you did and you light the end it can go off with a power boom. The hydrogen rich acetylene can be heated and excited. In this state it is violent about pulling in air to burn. And often creates a good explosion. So if you shut off the acetylene first it goes out rather lean and cold, with no large amount of fuel to burn. This shows what can happen to an area rich in acetylene. http://www.Rockwelder.com/Explosives/pipepock.wmv Sincerely, William McCormick
Reply:Here are individual frames of what actually took place there. Sincerely, William McCormick
Reply:Makoman1860,You were right on. Just too harsh a flame. Turned down to a softer flame and no problem. I just don't normally use a tip that small.Thanks,Tony
Reply:1)have often wondered why smith wants so much pressure. i can blow the puddle away if you dont throttel back with torch knobs. have heard that the gas flow is what cools the tip, but why twice the pressure of other tips?2)do torch knobs reduce pressure or just restrict volume?
Reply:Originally Posted by weldbead1)have often wondered why smith wants so much pressure. i can blow the puddle away if you dont throttel back with torch knobs. have heard that the gas flow is what cools the tip, but why twice the pressure of other tips?2)do torch knobs reduce pressure or just restrict volume?
Reply:thanks makoman1860-would you set it to 10 and 10 and throttle at the torch, or use lower regsettings and have the torch open wider?bottom line is you cant weld if the puddle has waves in it...
Reply:Originally Posted by weldbeadthanks makoman1860-would you set it to 10 and 10 and throttle at the torch, or use lower regsettings and have the torch open wider?bottom line is you cant weld if the puddle has waves in it...
Reply:Originally Posted by makoman1860They control both. Your torch has to orfices, one variable ( valve ) one fixed (tip). Your regulator is a fixed pressure. The combination of the size of your variable orfice (valve ) setting, and the pressure delta accross it ( regulator pressure to pressure after the valve ) will determine the flow rate FROM your valve. Your pressure AFTER the valve is controlled by the fixed orfice (tip) area and the flow rate through the tip. Mass flow rate is constant through the entire system, but is controlled by the delta pressure accross the most restrictive part of the system ( usually the valve unless its wide open). To make it simple:The Tip doesnt know the different between the following provided the flame is the same size in either case:A) Low regulator pressure with a large torch valve openingB) High regulator pressure with a small torch valve openingSo it is seen that the pressure BEFORE the tip, but AFTER the valve, will be exactly the same in either case.Now a lower regulator pressure CAN reduce turbulence in the mixing chamber BUT, may also cause the mixer to run warmer due to it not having the expanding gas to absorb some of the heat. But this is usually not even measurable. Hope this helps..
Reply:Originally Posted by weldgaultTrue, the pressure is the same before and after the valve, but the volume is not the same and the volume could be the difference in a good cut and a bad one. John
Reply:Originally Posted by El GrecoI was welding with a Smith MW202 tip without problems. When I shut off the oxygen the flame went out. I really don't think it burned back into the tip, it just went out. I turned off the gas and put it away for the night. I have never had this happen before. I just swapped out bottles the other day, so they are full. First question, does anyone know why this would happen or had this experience?Next, Smith is odd compared to the other manufacturers, in that they list 10 PSI for both oxy and acetylene for the all their welding tips.That makes no sense to me. I called them about this and they said "Yeah, that's what we recommend". Seems like too much pressure. Second question, why does everyone else list about 3-4 psi for an equivalent tip and Smith says 10 psi?Thanks, Tony
Reply:Originally Posted by weldgaultSorry, for all the different opinions, but you have to decide, by experience and I would be lerie of those who do not post their experience on this site. John
Reply:For a smith number two tip, I use seven acetylene and forty oxygen at the regulator. I set the acetylene till it does not come off the head, with just the acetylene turned on. I do this once to see how much it takes. Once I test it once I just know the setting. The oxygen, I open the main valve on the torch near the hose all the way or most of the way if I am in a hurry. Then I open the heating tip oxygen valve until, there is no change when I hit the oxygen cutting handle. I have been doing this for years. I will try to make a movie, when I get a chance.I like the forty oxygen because on a long hose instead of the oxygen and acetylene intermingling below detonating pressure, and then detonating the whole hose. The forty psi of oxygen should detonate the mix prematurely. Alerting you to a problem. Sincerely,William McCormick
Reply:Originally Posted by William McCormick JrI like the forty oxygen because on a long hose instead of the oxygen and acetylene intermingling below detonating pressure, and then detonating the whole hose. The forty psi of oxygen should detonate the mix prematurely. Alerting you to a problem.
Reply:Originally Posted by Alan NJust WTF does that babble mean?
Reply:One thing I should mention is that the Smiths number two tip although that is the smallest tip I like to use, because of clogging issues with smaller tips. The number two tip is really better suited for quarter inch, to 5/8" plate. Although you can severance cut up to two inches I believe with that tip. Sincerely, William McCormick
Reply:we have gone from welding to cutting...
Reply:Originally Posted by weldbeadwe have gone from welding to cutting...
Reply:I have welded since 1975 off and on, not professionally, just for my own stuff. Arc and oxy/acet, so I am not new.I thought I asked a pretty straight forward question and got one or two "decent" answers, that I appreciate. But somewhere this minor little post went to h--- in a hand basket.Some of the posts are scarry, I suggest anyone that a complete novice go to school and learn. Don't try to learn on here because some these guys may get you killed!At this point I am very doubtful if will pose anymore questions here. This place is bizarre! So gald I found it.Tony
Reply:Originally Posted by El GrecoI have welded since 1975 off and on, not professionally, just for my own stuff. Arc and oxy/acet, so I am not new.I thought I asked a pretty straight forward question and got one or two "decent" answers, that I appreciate. But somewhere this minor little post went to h--- in a hand basket.Some of the posts are scarry, I suggest anyone that a complete novice go to school and learn. Don't try to learn on here because some these guys may get you killed!At this point I am very doubtful if will pose anymore questions here. This place is bizarre! So gald I found it.Tony
Reply:Originally Posted by William McCormick JrWho are you referring to? I am stating things that are common place in the industry. Schools have to change with the books. I have seen it. You don't see books written by greats in the industry. Because they would be titled with titles that would be classified. Instead you get titles like "Increase Your Welding Knowledge Safely With Hubert Flowerpatch. No offense Zap, Ha-ha just kidding ya. I also know the people that often teach the teachers. But when a weird trend starts, the schools are the first to pick it up. And they are forced to. I have been in factories all my life. The pressures I stated are the safe correct pressures, used by any safe individual. For an example they came out and forced everyone to switch to environmentally safe ethanol gasoline, to stay competitive. But they forgot what it was going to be put in. Some of the ethanol is eating away fiberglass gas tanks. Corroding the inside of aluminum parts and other metals. But it is written in the books that it is good for us. "It is a safe and useful alternative fuel". If you are twenty miles out and your gas tanks lets loose, filling your boat with gasoline. And you are to afraid to turn the batteries on to use the radio. How dangerous is that?Actually the more common scenario is that the gel coat flakes off causing fuel line problems. As you take the boat out, in the ocean chop. The flakes are washed into the tank and sucked up and clog the filter. Leaving you stranded at sea. Or the aluminum gas tanks corrode. Will ethanol also absorb large amounts of water and condensation? Will this cause the vapors to become much more explosive? Should we ask the same people that told us it was a great alternative fuel? I think not. Certainly after safely using oxygen and acetylene for almost 30 years, I am not going to listen to them on how to light an oxygen and acetylene torch. They never came out with a new warning, or some evidence, that the lower pressures that were not standard, are somehow better then the higher older standard pressures. I have noted that dry gas usually ethanol can cause non-flashing fuels like home heating oil to flash. I have also noted that once you add in the dry gas, it seems to be a magnet for moisture. And strange chemical reactions in the tank. Sincerely, William McCormick
Reply:I know there are books from old, that state many things. Often contradicting one another. However if you are in the business you often just laugh at the books and the world that allows poor books to flourish. Lord knows I do not have the time to fix it. But I see the changes and often wonder what the heck will that lead to? We laugh at work because we are doing all we can. We do not have to feel bad. We are making products that I admit are being degraded by poor planing all the time. But we are doing all we can to make them as good as they can be made. I have made a bit of a hobby out of highlighting what America has been taught during different era's in Americas past. Often I have multiple books that show that none of them understood the actuality. But the funny thing is that if you read all three you can see how they all messed up. It often brings some of my greatest rivals to laughter at what they thought was true. And to be honest after a couple people see it, it is no longer the giant problem that you cannot discuss calmly. I imagine that if you are not really into explosives and you never think about what the pressures will do to the regulator and the gases in the hose. Then you might just look at it from a supply and demand kind of point of view. Maybe they decided that the torch itself only needed a few pounds why have more pressure in the hose?I know the gases can mix at these higher pressures 7/40 Acetylene/Oxygen. They will just detonate in the torch. Again and again and again. It makes you want to fix it right away. But the gases are not allowed to just mingle in the hose and then detonate the whole hose. I have seen an unlit torch that got clogged. And under these pressures it just kept creating a little pop in the torch. I never even used check valves all those years. For about thirty years now I have been using these pressures and no one has gotten hurt. No accidents at all. And everyone that I know who welds uses these pressures. So to find out that books or companies say to do something else is almost comical to me. If you are honest and look at all the little things that you find out going into a new industry or field. You realize that certainly it could be as I am saying. But that some people who write books just could not imagine keeping the pressure high so it would detonate the gases in the torch. The acetylene pressure is kept low because if you have oxygen or water vapor, in the hose when you turn on the acetylene there is a good chance it will not detonate. Until you clear the line with fresh acetylene. Sincerely,William McCormickOriginally Posted by makoman1860When you say higher "older" stand pressures, what are you referring to? My texts dating from 1924 through the 1940's are listing 1-3 lbs pressure for that orfice tip size. Injector style torches run a bit higher then the equal pressure designs, but nowhere near 7 or 40.
Reply:Originally Posted by William McCormick JrI am talking regulator pressure. You set the tip pressure with the torch valve that causes a very exact pressure and volume of gas to flow through the tip. The regulator pressure is set for safety, the tip pressure is set with the torch valves. Because a constant pressure is maintained by the regulator, the torch valves become precision flow valves. That do not allow more or less gas to flow. Because they are being feed regulator controlled pressure through an unchanging orifice. Just like Argon regulators and flow valves. Very exact. Someone else already mentioned that earlier, I am just reiterating. Sincerely,William McCormick |
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发表于 2021-9-1 00:01:23