O / A cutting help

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I'll probably get flamed for asking such a basic question, but what am I doing wrong if my oxy / acetylene cutting head won't make a clean cut?  The material seems to melt and re-seal after the torch passes by.  I've tried a variety of regulator settings, mixtures, speeds, etc. but 9 times out of 10 I can't make a clean cut.  I've tried cutting 16 gauge, 1/8" and 3/8" steel with 0 and 000 (Victor) cutting tips and have only once been able to make a respectable cut.  Are there any common newbie mistakes I need to check for and correct?Thanks...Last edited by WeldingRookie; 12-10-2009 at 01:02 AM.
Reply:you cannot make a clean cut on 16 gauge matural with a torch, cut it with a zip disk or plasma cutter .
Reply:Show us some pics of what you have cut, or attempted to cut.
Reply:Hello WeldingRookie, for starters, look to the Victor cutting guide to select your tip size and regulator pressures. Also, if you are cutting materials that are 1/8" and under try angling the torch head back so that you are pushing the cut, this will "fool" the torch, as it will be cutting through a thicker cross section and will cut somewhat cleaner. Thinner materials will require a fairly fast travel speed and a steady one. You will have to practice cutting to become really good at it, too fast, lose the cut, too slow and you will have the cut fuse in behind itself or possibly have excessive dross(slag) underneath the cut. Generally, 3/16" and over in thickness and the correctly sized tip and you can make your cuts with the torch perpendicular to the material being cut. Pay special attention to ensuring that you have a clean tip, this will generally be apparent when you depress the cutting lever and the oxygen stream is long and the torch makes a sizzling type of sound. Plasmas and cutting wheels on grinders and such are certainly better suited to thin materials, yet if you practice and pay attention to the other details you can do a pretty decent job as well. Good luck and best regards, Allanaevald
Reply:Angles, its all about angles but thin stuff is another story.
Reply:Thin stuff is a pain! I've tried cutting gauge material with an OA torch. Gave it up and switched to a grinder with a cutting disk. It was faster, easier, and looked better. I can cut thick stuff all day like a machine, but thin stuff just isn't worth the trouble.
Reply:Most guys have issues with it melting back together for several reasons. First the regs are adjusted wrong, usually with way too much acet and not enough O2. Second, partially related to the first, they have the torch adjusted too hot. They also move way too slow cutting. Last is that the tip is too big or that its clogged.As said post up picts of whats going on and what the settings are on the regs. Thin material is a PITA with O/A. It's really where Plasma excells, but that doesn't mean you MUST have a plasma. Zip wheels, nippers, O/A will all work, but not as fast..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by brent tyou cannot make a clean cut on 16 gauge matural with a torch, cut it with a zip disk or plasma cutter .
Reply:Originally Posted by OldtimerUhh, yes, you can.
Reply:heres a tip as well if you live in a cold enviroment like here in minnesota if i have to cut something small like i can carry i throw it in a snow bank for a few hrs until it gets really cold and cut it vs cutting it at room temp the cold stuff will cut like slicing cheese but if you weldit right away pre heat to at least  50 deg cold metal doesnt weld wellmiller maxstar 150   hobart handler 210 w mig conversion hobart 250 arc force plasma cutter    boston ind cutting torch miller performance auto darkening helmet milwalkee 14in chop saw 10,000 watt generator huge drill press and industrial band saw
Reply:You can cut thin plate with a tortch. Here is a link to how to cut 1/8" plate. 16 gauge can be cut the same way.I always tried to work with the oldest hand on the job to gain knowlege but now I can't find any.
Reply:Originally Posted by brent tyou cannot make a clean cut on 16 gauge matural with a torch, cut it with a zip disk or plasma cutter .
Reply:It takes a bit of understanding to troubleshoot your problems  You have a set of fixed or primary adjustments that you do before starting.  Tip size determines thickness you are going to cut.  000 is meant for light gauge like 16 ga.  I use a number 1 for 1/4 plate and if I want a perfect cut I go to a zero size.  The pressure of your fuel is not critical and usually stays less than 5 psi unless you are cutting several inches in thickness.The size of your flame should not be too much.  You should have a neutral flame when the oxy trigger is pressed.  I like a relatively quiet flame.  It takes longer to preheat but you are less likely to overheat and melt the metal.  If the metal melts it does not clear out of the kerf and welds back together   The pressure of your oxygen is important.  For a victor you only need 20 psi.  You will see people run 40 but it is a waste of oxygen unless you are cutting over one inch plate.  Most people run too high a pressure and waste gas.  Before you start clean your tip.  I know it looks clean and you want to get cutting but just clean it before you start.  It saves a lot of confusion later on when you get a bad cut.  Secondary adjustments are done on the fly as you cut.  The torch should be perpendicular to the plate until you go to 1/8th or less.  At that point start angling the torch forward to throw heat ahead and increase travel speed.  The acetylene cones should be adjusted to neutral and just off the surface,  No more than 1/8 above the plate.  You should heat the metal to kindling temperature.  It is not molten!!!  All you need is enough heat to allow it to burn when you add oxygen.  Travel along making your cut.  If you travel too slow the cut will stop and the edges will tend to melt.  Travel too fast and you lose the cut because the preheat cones have not been able to bring the steel up to kindling temp.  You can tell if someone is doing a nice cut from fifty feet away simply by looking at the shower of sparks coming off the bottom of the plate.  Too slow and the material drops off in globs.  As you increase speed the shower becomes steady.  Just before you are travelling too fast and lose your cut you will hear a "phft phft pfht" sound sorta like sputtering.  You will learn to compensate for improper primary adjustments.  If you choose too much preheat or too large a tip you will have to increase speed to compensate.  The cut is more ragged but it gets the job done.  Too small a tip and too small a preheat will demand that you slow down... usually you will get a nicer cut but you have to be more patient.
Reply:Thanks everyone for all the helpful input.  I tried the angle trick on my 16 ga. scrap piece and it definitely helped.  It also helps to know that thin steel is not super easy to cut cleanly with an O/A torch.Thanks again,-Mike
Reply:Use guides.  Your cuts will be much cleaner.  You'll develop the steady hand, eventuall.  At that point  you can start trying the free-hand stuff.
Reply:3 things to remember:(1) You don't melt the metal out of the kerf, you actually cause it to "burn" or oxidize away and it is the oxygen coming out of the central hole in the tip that does that once the metal is heated by the preheat to the point it burns.(2) The smallest tip size you can do the cut with will produce the cleanest, narrowest kerf.(3) The guy that suggested a guide had it right...often when I need a guide for some cut, I just clamp a piece of scrap angle iron to the work and drag the head of the cutting torch along that. Then all you really need to do is keep the travel speed nice and consistent and at the correct speed. Oh, yeah...the distance between the work (cut) and the tip has to be right and be constant, too.Well, OK..I guess it is 4 things...(4) As mentioned above, Victor provides settings and tip sizes for their cutting rigs and they DO work, provided you use them and set the flame right before you start cutting. To check the flame, set it with the CUT LEVER depressed so you can see what kind of flame you have when the torch is actually doing the "work" it was designed for.