What's wrong metal melting back together while cutting?

admin

I have a harris torch a few years old and a clean tip might need new tip i don't know. When I am cutting any size metal it melts back together what am I doing wrong?
Reply:You may be moving to slow, or cutting with too hot a flame.  You could try speeding up the cut a little bit, or back down your torch a bit.  When I cut, the metal usually is still stuck together slightly, but I just tap it with a hammer, or bend it at the cut line by hand (be careful not to burn yourself), and it comes free just fine.Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Also make sure the blowhole in the center of the tip is cleaned good w/ a tip cleaner the proper size ie: the same size as the hole.                                    MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:Also depends on what thickness of steel your cutting. thinner than 3/16" is usually harder to cut because it likes to reform.Miller Dynasty 300dxSpeedglas 9002XMiller Spectrum 375 XtremeLincoln PowerMig 255xtLincoln PowerMig 140cMilwuakee Portaband
Reply:I suspect you might be cutting with too light a flame.  Remember when you set your torch it should sound like a train, or blowtorch; not quiet.  As others have said make sure all holes are clean but the heat setting should sound loud.  It should be so strong that if you cut the O2 the acetylene flame will probably blow out.  Then make sure you have enough O2 pressure to make a blow sound.Heat first, then hit the cut lever and move smoothly, really shouldn't form back.  I cut easily 1/2 inch with a normal size torch, nothing large; can't remember the tip size but not the hobby size, just standard torch.jbman45Century 230A AC/DCLongevity 200 Multifunction MofsetLongevity 200PI Multifunction IGBTVictor Oxy/Weld&Cut5HP 2 stage compressorTractor; tools and 40  years of collecting fine tools.
Reply:May sound like a wet blanket but I've yet to see 2 journeymen use the same torch set-up. Typically when my cut would melt back together; I backed off on the heat and that corrected the issue
Reply:After you cut through, back off of your oxy lever. Use only enough to blow through. Also you want to cut with the most speed you can. On thin metal, if you don't lose your cut from going to fast every once and a while then you are probably going to slow.
Reply:Originally Posted by BobAfter you cut through, back off of your oxy lever. Use only enough to blow through. Also you want to cut with the most speed you can. On thin metal, if you don't lose your cut from going to fast every once and a while then you are probably going to slow.
Reply:All good suggestions.But on thin metal,  try "leading the torch" with the flame at about a 60 degree angle from the surface.  This will help.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Here is a guide from Harris's site:http://www.harrisproductsgroup.com/p...SonCUTTING.pdf
Reply:I had the same problem this weekend cutting a tank.  In a 60" cut, I had about a foot of cut that looked like it was cut with a plasma.  The rest melted back together.  I tried speeding up, and slowing down...nothing helped.  When I sped up, it stopped cutting.
Reply:Pookie,You could try backing down your torch a bit, maybe lower your acetylene pressure...  Once the cut is started, it's actually a chemical reaction that is cutting the metal, not the heat from the flame (a lot of heat is released in the reaction though).Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Wow Too hot, too cold, point it this way, point it that way.I think what were saying is, is that you're gonna have to screw around with it and figure out what your doing wrong. Yup
Reply:When cutting, there should be no "melting."  If the steel is melting at all, it's from to much heat... either from your torch being too hot, or from moving too slowly.  Remember, it's the oxygen that does the cutting, and you only need enough heat to get the oxidation process started, not enough to melt the steel.  Try reducing the amount of preheat and/or increasing your travel speed.  If it's still melting together, you might need a smaller tip.Work HARDER, not smarter! ------------------------ Miller Bobcat 250Millermatic 251Lincoln Precision TIG 185Hypertherm PM 600Hobart 135 HandlerOxweld 400 FlameMaster
Reply:Originally Posted by BurnitWow Too hot, too cold, point it this way, point it that way.I think what were saying is, is that you're gonna have to screw around with it and figure out what your doing wrong.
Reply:If one has a really steady hand, get your cut started and have someone pinch the acetylene side of the hoses shut w/ pliers. If you're REAL STEADY and don't stop forward movement, it'll keep on cutting w/ just the oxygen.                               MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:There's the sound..........can't describe that over the webTravel speed.........can't describe that eitherOnly thing I can describe is watching for a steady stream of sparks coming out from underneath the metal you're cutting.  It's the molten steel being blown out by the oxygen stream from the center hole in the tip.BIG THING WITH A HARRIS TORCH IS TO KEEP THE TIP CLOSE TO THE STEEL.  The Harris has a very short preheat flame (the flame coming from the set of holes in a circle around the outer diameter of the tip), and these literally have to be touching the metal.  It's a very close thing.  Torch maybe only 3/16-1/4 inch offa the steel.You can get around this by using a tip that is too large for the thickness your cutting, Preheat, start the cut, then lift up, and just use the O2 to keep the cut going.  It's actually the high pressure 02 stream that does the actual work anyhow.  You'll use a little more 02 and Acetylene than with a smaller tip, but you don't have to fool around with changing tips all the time.  You modify with distance from surface, and speed to compensate.  Steeper angle with thinner material, or faster travel speedAnd invest a couple of bucks in a set of tip cleaners.  A lot of cutting complaints come from dirty tips.Burn on dude!!!!!"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Oh, crap.........I just pretty much said what mla2ofus said.  But ya get my drift.  LOL"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by PilotDanPookie,You could try backing down your torch a bit, maybe lower your acetylene pressure...  Once the cut is started, it's actually a chemical reaction that is cutting the metal, not the heat from the flame (a lot of heat is released in the reaction though).
Reply:Originally Posted by mla2ofusIf one has a really steady hand, get your cut started and have someone pinch the acetylene side of the hoses shut w/ pliers. If you're REAL STEADY and don't stop forward movement, it'll keep on cutting w/ just the oxygen.                               Mike
Reply:Originally Posted by waginAre you saying that after starting a cut, I can turn off the acty and the oxy will continue to cut the metal? I gotta try that. Is this how and oxy lance works?
Reply:Originally Posted by waginAre you saying that after starting a cut, I can turn off the acty and the oxy will continue to cut the metal?