Oxzy/ACET pressures?

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I need advise about pressures to set my 80's model welding unit, both for cutting and for welding/brazing.I have an older welding/cutting outfit I have not used for years.  I lost the pamphlet for it but my memory says this basic information wasn't clear there anyway.The unit is off-brand but interchangeable with the small Victor unit (sorry I didn't get the name before typing this)I have small gas bottles, I think the ACET is called a "B" bottle and the OXY matched that size.I inherited two sets of tow-bars for a factory built home and cut them apart today with this unit.  The material is about 1/8" I-beams and 3/16" angle spreaders.I used 5 lb ACET and 15 lb Oxy and had no luck.  I cranked the Oxy up to 25 lb and had reasonable luck but slag immediatly filled the area behind the cut about 20% of it.I searched Google for tutorials, welding pressure, welding manuals and several other logical questions but just got millions of ads and no useful info.Can someone direct me to an internet site giving BASIC information to novis small acet welders/cutters or better yet give me some basic advise here.By the way this site has given me much information and entertainment, just not exactly what I need this time (including a search of the site.)
Reply:http://www.weldingweb.com/vbb/showthread...t=oxy+pressureDrivesector Hobart Handler 140Hobart Handler 180Ready Welder 2Hobart Air Force 400Airco Stinger 225Of all the things I've lost, I miss my mind the most."OZZY"
Reply:I'm Sorry, I did what I hate other people doing. I didnt read the complete post before I replied. The above thread is not what you are looking for.Drivesector Hobart Handler 140Hobart Handler 180Ready Welder 2Hobart Air Force 400Airco Stinger 225Of all the things I've lost, I miss my mind the most."OZZY"
Reply:I looked around and found something you may be interested in looking at here http://www.esabna.com/EUWeb/OXY_handbook/589oxy5_1.htmMabe this will help youDrivesector Hobart Handler 140Hobart Handler 180Ready Welder 2Hobart Air Force 400Airco Stinger 225Of all the things I've lost, I miss my mind the most."OZZY"
Reply:Drivesector-thanks for the intrest, but that site also doesn't indicate the info I need.  This is what is says:quote:"Be sure to use a cutting nozzle of the size recommended by the manufacturer of your equipment for the thickness of steel to be cut. Adjust oxygen and acetylene pressures to the specific levels recommended in the instructions supplied with your torch or cutting attachment. Then put on goggles, light the torch, and adjust the preheating flames to neutral with the cutting oxygen valve open"But please keep searching for me-I apreciate the effort!
Reply:Drivesector-that first forum message wass "almost" what I needed except it was propane gas.  I guess maybe I was almost in the neighborhood with 5/25 but still wonder how to avoid the slag problem.  Maybe its partly the result of tremoors I have in my hands, although my wiggles seemed to actually improve the cut LOL.
Reply:Try thishttp://www.stanford.edu/group/prl/do...tml/OAweld.htmDrivesector Hobart Handler 140Hobart Handler 180Ready Welder 2Hobart Air Force 400Airco Stinger 225Of all the things I've lost, I miss my mind the most."OZZY"
Reply:While neatly done or pretty off hand cutting with a O/A torch is more of an acquired skill, everyone should be able to at least accomplish the task with fairly good results provided you have a tip that is close to that recommended for the thickness and you have the set-up and pressures right. To accomplish that it is really very important that you know the brand and model of your torch. Do you know that or can find that out?I should add that if you have something like the victor junior I would have either the -0- or -1- tip on there running with about 4 to 5 on the acetylene and 25 to 30 on the oxy.Last edited by Sandy; 12-06-2006 at 09:58 PM.
Reply:Within reason, the pressure settings and tip size are not as critical as flame adjustment and torch handling technique.  You could probably push your oxygen pressure up higher even than 25 psi, observe acetylene limits. You don’t have to hold the torch perpendicular to the work. You could practice cutting this thin stuff by jetting through from one edge.Keep this concept in mind - Once the cutting or burning has begun, the metal itself is fuel. You are not melting or blowing away the steel, you are burning it. In fact on thicker plates and with a steady torch head, cutting can continue without fuel gas. Sounds like excess preheat or too slow of torch travel is “welding” your cut closed.Don’t feather your oxygen lever. Get an idea for the capacity of your tip and adjustments by testing to see how deep  you can cut into a plate from the edge. Practice practice practice. Oxy fuel can produce extremely high quality cuts that need no further finishing.
Reply:The method I’m trying to describe for cutting from the edge is this; You can rest just the edge of your torch tip on the edge of the work. In a way that none of the orifices are blocked. Flame turned away from what will be the cut.  Now when your ready to cut you can preheat just a little spot and  “roll” the torch head through the cut. This method gives you a steady rest to work your torch from. It’s probably not in the book, but you can make  fast, clean and straight cuts this way. Practice practice. Of course tip capacity and pressure  settings must be sufficient to cut the entire length or thickness of your cut.
Reply:Hey knotbored, After you think you have your torch adjusted, hold the oxygen lever down for about 7 seconds and watch to make sure that pressure drops will not be diminishing your flame or cutting jet during cuts.Don’t worry about the age of your torch set. Quality cuts could be made with 100 year old equipment.Last edited by denrep; 12-06-2006 at 11:32 PM.
Reply:Great information, let us know how your O/A cutting pans out. My O/A setup has gotten me out of a few binds...love it!John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:All of this is great information.  Its too early to go check make/model but I will do that later this morning.By the way-these house tow bars I got will be perfect for welding practice for me and I am told most buyers have no use for them when a house is moved in, but they are disposable by the dealers.  Great source of material.I got 4 I beams  about 7' long and 6 angles about 4' plus two trailer jacks.  I just needed to chop them apart so I could carry with my little Kabota tractor.
Reply:Don't know how much experience you have on the torch, but a lot of novices (no insult made here) don't know that on a cutting torch you open the oxy valve wide open at the base of the torch. The single valve further up the neck is the one you will use to set your flame, the one at the bottom next to the acetelyne valve is to supply your cutting oxygen (as well as supplying the 2nd oxy valve). Another common cause of the problem you describe is too slow movement. Experiment with moving the torch more quickly across the work, you'll be suprised how fast you can go and how clean the cut becomes. Not saying these are the problems, just that they are common ones. Good luck!If you don't have the time to do it right, then you definitely don't have the time to do it over.
Reply:A little more information.The brand of the torch set is Uniweld.  I found their internet site but it offered no manual or help.Clanweld-yes that part is information I did remember.  I had the right knobs adjusted.  One part confusing me is "losing" the cutting action.  Memory I have is continuing along as you describe but this time every inch or so the cut would just stop and need more preheating to pick up the cut again.Can someone explain what the flame for cutting should look or sound like? I set about a 9" acet flame, added oxy till the hiss got noticably louder, backed off oxy a tiny bit.  Bright cone was about 3/16"- 1/4" long set for preheating.Lower handle knob was full on with Oxy set at 20 Lbs (plus sampling pressures around there.  Cut would start fine-then slag up-or stop after about an inch.
Reply:Once the cut is started, the steel burns because of the oxygen stream from the cutting orifice; no further preheat flame should be needed to maintain the cutting action unless you lose track of your line. Contrary to the idea some have that you squeeze that handle to 'blow away' the melting steel. The preheat flame is just to bring the edge of the steel up to the melting point so you can introduce the oxy stream and begin cutting. Your preheat flame is set up according to the guage of steel you are cutting, bigger flame for heavier steel, just so you aren't preheating for 20 minutes to get the steel hot enough to cut. Set the flame to neutral by adjusting the gas so the 2nd lighter blue cone just dissapears into the firs darker one. Dont know why you are having a problem, might be you are holding the torch too far from the work, I try to keep about 1/4" to 3/8" distance from the cut, track straight and steady along the line to be cut. Hope this was helpful.Last edited by Clanweld; 12-08-2006 at 02:40 PM.If you don't have the time to do it right, then you definitely don't have the time to do it over.
Reply:Originally Posted by denrepHey knotbored, After you think you have your torch adjusted, hold the oxygen lever down for about 7 seconds and watch to make sure that pressure drops will not be diminishing your flame or cutting jet during cuts..