Oxy welding & gas pressure

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I'm a newbie, pretty much, to oxy-acetlylene welding - though I've brazed a fair bit in the past.I was getting some advice about a tricky welding situation, and a couple people recommended that I use a larger welding tip and that I keep the inner flame (blue cone) 1/16" from the metal or puddle.But as with all newbie oxy welders, I've experienced a fair amount of popping. Trying to keep the cone 1/16" from the metal, am I right in thinking you'd have to depend on a high enough gas working pressure (plus keeping the tip angled at about 45 degrees) so that you don't get a lot of popping?  If so, what sort of pressures on the acetylene and the oxygen?Joel
Reply:The popping is caused from insufficent pressure. I know that the manufacturers and half the people on here recommend setting your regulators for the recommended tip pressure but a lot of us use a simpler way to do things. The size and length of your hose has a direct effect on the pressure delivered to the torch. The valves on you torch are also pressure regulators in a sense. They act as a choke for the pressure sent to them. I have always used about 100' of hose. Walking back to the bottles or climbing down off of something takes a lot of time. I and a lot of others set our regulators to cut and just leave the setting alone when we switch to welding. I have always favored 10# acetylene and 40# oxygen for 95% of my cutting. All you have to do is set your welding flame with the valves on your torch, need more or less gas, it's instantly available. Cutting thin material, just feather the cutting oxygen with your thumb.
Reply:I bought a torch about 12 yrs ago.  It had 13 welding tip and 4 cutting tips and no chart for pressure setting. Out of fustration I decided adjust the pressures from the tank. I would fully open then light the acetylene at the torch.  Then add Increase flow from the tank until the flame jump from the torch.  Bring the flame until it just touches the tip.  From there I do the same with Oxygen to get a just oxidizing flame.  Finally I fine adjust with at the torch.My torch is a Meco Weldmaster.  I have never seen a chart for it, nor do I know how their tip size corresponds other tips.Pressures usually come out around 5psi Oxy and 3psi actylene for a my size 4 tip.I have never had much success with tip sizes 00 through 1.
Reply:The biggest problem I found with having super high pressures for welding tips is the inability to adjust the torch.  With a too high pressures a crack of the torch valve and you at max tip capacity.  Make for difficult lighting and adjusting.
Reply:Oldtimer wrote: "The popping is caused from insufficent pressure."Okay.  Well, I'm using 18 ft. of hose.  I got used to generally setting the pressure at the regulator at 4 pounds acetylene, 4 pounds oxygen.  Obviously, I set it higher for cutting, but this is how I mostly set it for brazing and welding with medium-size tips.But using a #4 Victor tip, and trying to keep the cone very close to the metal, I've been thinking I should increase the pressure to 5 pounds on each regulator - and maybe I should be setting it higher.So from what I'm hearing, no matter how close I get to the metal, it shouldn't pop if the reg & torch pressure is set high enough.  Am I right?J.
Reply:So from what I'm hearing, no matter how close I get to the metal, it shouldn't pop if the reg & torch pressure is set high enough. Am I right?
Reply:Im not a Oxy/Ace professional, but I noticed if you get to close to the welding material, it will make that popping sound no matter what settings you have it on. My teacher actually did a demenstration on that and he said what its from is the Oxy/Ace is combusting before it can actually light a flame. Thats my 2 cents.
Reply:Joel, If you are keeping the inner cone of your flame at 1/16' or better from your metal your torch shouldn't pop unless your gas pressure is too low. You don't need to keep the inner cone right down against the metal. If you can't get the metal hot enough without it being right against it, go up one tip size. Any tip you use if stuck down against the metal will pop whatever pressure you are running on it. Touching the inner cone to the metal is a no-no. By not worrying so much about gas pressure you can have a fairly wide temperature range with each size of tip. I know that the books don't tell you this and a lot of instructors don't either or just don't know. A lot of welding with any process is experimenting and learning what you can and can't do. Just don't ignore any safety rules. I have had no problems adjusting my torch, welding or cutting, with the pressures I mentioned.
Reply:Torch pops/backfires are due to tip overheating- not enough gas flow to cool the tip and/or (as said) getting the tip too closeI don't bother with the regulator gauges to set pressures. With the bottle valves 'on' and the regulators 'off' open the acetylene torch valve 3 turns, screw in the regulator until gas flows and light the torch. continue screwing in the regulator until the flame 'leaves' the tip. Back the regulator off until the flame re-attaches- acetylene pressure is now set for THIS tipOpen the oxygen torch valve 3 turns and then slowly add oxygen via the regulator screw until the 'acetylene feather' just disappears (neutral flame)- this is the largest flame for THIS tip.Regulators are now set for this tipTurn the oxygen torch valve off and then close the acetylene torch valve until the flame begins to smoke, open it again until the flame stops smoking. Open the oxygen valve again to get a neutral flame- this is the minimum neutral flame that can be used with this tip without backfiring
Reply:Also, different joints might require different pressure.  A tee joint concentrate lot so heat at the tip, hence more torch popping if adjustments are not necessary.  Downhill creates overheating problems also.Just my experiences though.
Reply:I was taught to set my regs at 40 and 10 respectively. I have been using those settings for 40 years now for cutting, welding, brazing and heating using everything from a 00 cutting tip to brazing using the big rosebud with no problems other then sometimes needing more oxygen on really heavy plate. Now mind you this was with Victor and Harris equipment so I can't speak for other brands.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Alright OldtimeI tried 10 and 40 psi as setting.  It adjusted fine with my no.4 tip.Suck up a unnessary amount of gases, though.
Reply:sorry double post.
Reply:Originally Posted by tapwelderAlright OldtimeI tried 10 and 40 psi as setting.  It adjusted fine with my no.4 tip.Suck up a unnessary amount of gases, though.
Reply:Tap, if you have it adjusted right it is using the same amount of gas whether you set it with the torch valves or with the regulators. More gas equals more flame.
Reply:Yeah,  I had it maxed coming out of the tip.
Reply:I been thinkin 'bout this tho and my experience using high pressures.High pressures work. However, the problems I have--  High pressure create high flow at the tip thus pushing the puddle more rapidly.  The higher the pressures at the needle valve the more speed the gases have coming out of the torch.  Recommended pressures might be difficult to find but welding will be easier, especially for beginners.  It definately affect the minimal adjustment on my torch, thus more gas consumption.     Could be just what you are used to.   I learned low pressures.
Reply:Originally Posted by tapwelderI been thinkin 'bout this tho and my experience using high pressures.High pressures work. However, the problems I have--  High pressure create high flow at the tip thus pushing the puddle more rapidly.  The higher the pressures at the needle valve the more speed the gases have coming out of the torch.  Recommended pressures might be difficult to find but welding will be easier, especially for beginners.  It definately affect the minimal adjustment on my torch, thus more gas consumption.     Could be just what you are used to.   I learned low pressures.
Reply:Joel_BC, I am also a newbie but I was curious how thick the metal is you are welding if you are having to consider going larger than a #4 tip? It could be you could use more pressure with a smaller tip and stop the popping.  Also help with using up the gas. Again don’t rely on me too much I am still green but something to think about. Oldtimer and some of the others sure have helped the couple of times I have asked however - bet you a dollar when you go try their advice it works!Here is a link that also sure helped mehttp://www.esabna.com/euweb/oxy_handbook/589oxy1_1.htmDon
Reply:Let me see if I can explain this a different way. The valves on your torch are a pressure regulating device just like the regulators in a sense. The difference is the regulator senses pressure and closes when the preset pressure is reached. The valve holds the setting that you set and will maintain it as long as the tip (in this case) is open. Set your regulator to flow 1 cu. ft. of gas and it will hold that flow automatically. Set your valve to hold the same flow and it will hold it until YOU change it. Since the regulators show psi that is what we work with. If it takes 1 psi of gas pressure to produce a neutral cone 1/4' long with a certain size tip it can be set with the regulator or the valve. For example, set the reg. at 10 psi and you can reproduce the exact same length of cone with the valve. If the cones are the same length in each case the amount of gas flowing thru the tip is the same whether set at the regulator or at the valve. If the gas flow changes the flame changes.
Reply:Originally Posted by InTheSticksJoel_BC, I am also a newbie but I was curious how thick the metal is you are welding if you are having to consider going larger than a #4 tip? It could be you could use more pressure with a smaller tip and stop the popping.  Also help with using up the gas.Don
Reply:I thought the valves at the torch flow.  Pressure set at the tank.  High pressure mean high velocity at tip regardless of how much you open the torch valve.Sorry guys,  I over this now.LaterCorrection: the valves only control the flow, not regulate.Last edited by tapwelder; 04-06-2008 at 05:31 PM.
Reply:Anytime I get popping, I run a tip cleaner thru the tip. Remember, a tip cleaner isn't a file. If it doesn't slip in easily, use the next smaller one (or two). Some guys turn the oxy on a little while they're doing this, to blow out the cleanings instead of them falling into the torch. hotrodder, that sounds like a very good method for setting gauges without having the manual available. 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Thanks for the discussion and all the suggestions, guys.Joel
Reply:hotroddder i welded some 3/16 ms angle back to back  yesterday  setting my tip your method and it was excellent..enough gas (,my low side regulator gauges showed around 4psi each, by the way, and smith recommends 10 and 10.) available, but    nice and gentle on th puddle...it seems setting the regulators with the torch valves 3 turns open makes a difference- i never had  my acetylene valve anywears near that far open before.Told you so . Can't claim it as my method (it's been around for eons, probably as old as the torch itself) but it's still used 'cause it works so wellIt's common for the gauges to end up reading different to the recommended settings but the tip doesn't care about pressures persay- it wants enough gas flow to keep it from overheating and not so much that the flame tries to blow itself outIf the regs are set high and the torch valves are used to throttle the gas flow the resolution of the valves suffers- tiny movements = big changes to flow.If you prefer, you can set it so that the torch valves aren't as far open- resolution will drop but there's a big, comfortable window between the torch valves having such a big influence on the flame and them becoming little more than an on/off switch
Reply:fotos attached, 1/4" and 3/16"  angle , nice soft flame and puddles Attached Images
Reply:Your angle-iron bead looks good.  I've been practicing on 1" angle iron, with stock that's a shade less than 1/8" thick.  I've had no trouble welding the portion that you're illustrating (the bottom, or narrow edge, of the T).  I've had trouble getting a tidy, penetrated bead along the top of the T -- my puddle tends to go wide, maybe partially because the "fin" of the two pieces of angle iron sticking down below (the vertical of the T) is acting like a heat sink.Anyhow, the heat does seem to spread and the puddle isn't so narrow and the bead is often turning out 3/8" wide and untidy.  It's welded, but looks like sh-t.Wish I had a digital camera set up, I'd send some pics... but I don't.  Still, there are so many experienced guys on this forum that I'll bet you can picture this newbie's problem pretty well.J.Last edited by Joel_BC; 04-15-2008 at 10:31 AM.Reason: spelling
Reply:see attached fotos;i wanted to see if i actually had anything, so i split it apart and there was some connection tothe top of the individual angles, but zero penetration between the two angles. i cleaned it up, clamped it together and ground some groove in half of it. will re-foto with a dime before i try to stick it backtogether. joel-bc ,have you broken any of the ones you've made? Attached Images
Reply:Post #29: ya has ta grind that top edge OUT. You're welding 1/4" 'base' metal. More than 30*, less than 45*; each edge. And turn up the heat, I'd use a #4 on my OLD Craftsman O/A; Harris, me thinks. 8# or more, each, O/A. You're no where close to penetration, turn 'er up.With O/A, you can always 'flip' the torch away, to cool the puddle.For a dollar, I'll measure the ID of the #4 tip. Good luck, Craig 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:We have a handy(I hope) Acetylene welding tip reference chart located at: http://mewelding.com/welding/?page_id=100
Reply:i have smith setup- my smith  tip #  mw209 is rated for 3/8"ms at 23scfh, 10psi gas .. hole is big enough to take a piece of tie wire, which i measure at .065" diameter-book says a # 49 drill..
Reply:ground it out , puddles it together- seemed like too much pressure at the tip, puddle was blowing around , couldnt get a good puddle/dip thing going at all.   gave it overnight and broke it- i didnt break that easy, but i dont think im seeing penetration.. Attached Images
Reply:I really think you have a difficult joint to weld.  I think you probably need more preheat on the flange.  Your previous weld look pretty good.  Go back to that  and perhaps try multipass in the Vee.  I don't think you Vee is deep enough.Try brushing your weld of before showing it.  It look like you might have an oxidized weld, but I am just guessing.   Again, it is not a easy joint so don't get frustrated.  I think the flanges poses problem if it is not preheated.Last edited by tapwelder; 04-23-2008 at 08:03 PM.
Reply:Looks oxidized to me.
Reply:Wow,i dont know where to start.#1 use ONLY the O/A settings your torch maker calls for for the tip you are useing in your manual !!! #2 I think your useing to large a tip size id be using a Victor #2 for what your doing.#3 let the PUDDLE melt the filler rod it looks like your melting off chunks and moving on.#4 Use filler rod ment for O/A welding not coat hanger! Make SMALL circles and dont stop circling #5 be safe,have fun. if you click on my name and look at my old posts there are a few about welding and cutting O/AVictor SuperRanger O/A                                         Solar migLincoln Powermig 140Southbend 9in lathe350# kohlswa anvilMiller Maxstar 150 stl etc....
Reply:One way to check for complete penetration, while you are welding mild steel with oxy acetylene,  is to observe the number of sparks that are coming from the molten puddle. Very few sparks indicate the penetration is not complete, a large number of sparks are produced when there is excessive penetration. Maine Welding Company & Wrought Iron Powered by Custom Web Development
Reply:Confused by sixty different answers/opinions/recollections in response to your questions about O/A?  Want a free reference book on OA welding, cutting, and heating and O/A safety?  Go to http://www.thermadyne.com/victor/content/view/93/268/ and send an e-mail to the nice folks at Thermadyne asking for Manual No. 56-0114.  Did I mention it's free.TeddCoHTP Microcut 400 & Invertig 160DC  Smith Dual Guard MD-510 OA Rig  Lincoln SP135+  Hobart Stickmate LX 235/160
Reply:Teddco, thanks.  I tried to find their e-mail on the Thermadyne site, but had no luck. Looked around on various pages (but maybe didn't look around far enough?)... didn't see it.  Then I tried sending e-mails to [email protected] and also office@...   but no luck that way, either -- bounced back. Any help?...Joel
Reply:Or go get the pdf of TC-9-237. http://www.metalwebnews.com/ed.htmlHas a couple of chapters on Oxy-fuel equipment and welding