Posted a couple of weeks ago with this problem. Got some good advice. I've tried it all and still have the problem. I'm cutting 5mm plate. Getting a good clean cut on the top surface. I can see the flame blasting through the full thickness but the cut is filling with slag to about half the depth of the plate. I have to use a big arsed hammer to break the piece free. Tried more flame, less flame, closer / further away with the tip. It must be something real simple (read stupid) that I am doing or not doing. HELP Pete
Clean tip and set up torch right, A little too hard to explain here, Cutting is an art, steel just falling away when you finish a cut is a LEARNED skill, it doesn't come to a beginner for free. Get a pro at a shop to show you. Lots of weld supply stores here have places to test drive the equipment. Maybe you can talk a pro into giving you some pointers. With due respect there isn't anything simple or stupid to making a clean "fall away cut" with an oxy acet rig. If sparks come thru the back of the plate, you are thru- move on. Your speed may be too slow, but More than likely too fast, most beginners weld and cut too fast.
Angle the tip in the direction that you are cutting. On that thin plate, you can probably almost lay the tip down flat in the direction you are cutting. Get the metal hot and try that.
Too many novices don't heat the metal up before torch cutting. You can't expect to get a good clean cut if you jam a hot flame to a cold plate of steel. Spend a minute or two warming the steel up and you'll find that less of your cutting heat gets dissipated in cold metal and your cut will be easier and more consistant. Sawracer is correct, alot of it is knowing how to adjust your torch and where to set your regulators along with torch angle and speed......something that's difficult to learn by remote control.
Thanks guys. I've tried slower and faster, cleaned the tip, tried a smaller tip. I'll persist. Try a bit more angle. I'm not a beginner as such. Been using this gear for a number of years but never been taught how to do it right. I've always just winged it and usually get a good result. That's the problem. When I get it right, I don't really know what I did so I can repeat it. Pete
Like it was said earlier try cutting faster also turn your oxygen pressure at your regulator up a little bit also have the oxygen valve at the torch base fully open BTW what is a mm? Is that one of those Metric measuring thingys?? Dawg
If it breaks away with a hammer you are not going too fast. The problem is more than likely that your torch is setup too hot for the speed you are traveling ( you are actually melting the metal back together behind your cut). You may have too large of a tip on the torch as well. For something as thin as 5mm you do not need to preheat the steel. Try turning the gas waaaayyyyy down from were you have it set, and adjust the oxy as needed. Good Luck
I've noticed that when I get metal clinging to the cut it's because I waited too long to start the oxygen and a puddle almost formed, then when the oxygen is triggered it flows back behind me instead of just disappearing. I get the best results when I start the cut as soon as the oxygen will get all the way through - a weird habit to learn since I learned to weld first. I'm a complete newbie at cutting though, so my advice prolly aint worth much...
I've had that problem too - with the slag re-forming a bond as the torch moves away from a previously cut area. I started using a bit more oxygen, to really 'blow' the crap outa' the way. Don't know if I'm doing it right, but I've cut steel up to 3/16" (close enough to 5mm) and had okay results. Hope this helps. -bill
Yeah, having 25 psi (if memory serves me right) or more of oxygen really helped, another weird thing to get used to after welding forever with 5. I think the video I have recommends 25-35 psi... AND REMEMBER - Acetylene is NOT stable over 15psi.
.heres my 2 cents...your tip should be a..00..make sure its clean inside but do not over bore the holes as they can go out of round very easy..make sure the outside of the tip is free of nicks and mushrooming on the end..file it if it doesnt have the look of a new tip...acetylene at 5psi and oxygen at 20psi..turn on gas and light your torch...ajust flame so you have about 3" of laminer flame as it leaves the tip..turn on oxygen and adjust to a neutral flame..depress cutting oxygen and readjust flame to neutral...your heat should be low enough so it will take alittle while before you can begin cutting...angle in the direction of your cut about 2/3 degrees...you should see a steady stream of moulten metal exiting the underside of your plate..not a shower of sparkes this will indecate your moving to fast..hope this helps
Heaps of stuff here to try. Think I'll print it out to refer to and scratch things as I try the (if they don't work). It could be that I have too much heat, because I've tried cranking it up a bit and that doesn't help. I'll check the settings on my regs too. I have just gone by the markings on the gauge faces that actually say, "weld", "cut" etc. Not very scientific to say the least. I don't think I'm travelling too slow. If I go faster I outrun the molten pool. Thanks fellas. When I master it I'll let you know Pete
move faster and angle the tip more towards the uncut metal preheating it as you go as stated previously and practice practice to adjust the flame I get the gas so its not smoking then turn on your oxygen til you get a nice blue tip hit the cutting oxygen and see if the blue flame gets longer if it does you need to adjust your oxygen mix to more just til it doesn't change when you hit the cutting oxygen, hard to describe in proper lingo but thats about the best I can do
5mm is 22 gauge in the U.S. Most of us have cutting attachments rather than specialized cutting torches. The attachment goes on instead of a welding tip. Using this type of attachment, you open the oxygen all the way on the handle, and use the oxygen adjustment on the cutting attachment only. I've seen where people try to use both oxygen adjustments, and if you're doing this, then it will never work right.
Guilty. Maybe that's it. Like I said earlier. It's gotta be something simple (stupid) Tried reducing pressure at the reg, tried pre heating, tried angling the tip (which is clean). Could be something as simple as how I adjust my torch. Nearly out of gas now! Anyway, I am getting the job done. It's just needing a lot more clean up than I would like. Thanks heaps for all your input guys. I'm feeling pretty dumb. I can weld OK and I can pinstripe and spray paint and.......just trying not to feel so dumb. Pete
Let's start with this. This is the neutral flame. It is the ONLY flame you should weld with and what you should shoot for when adjusting your preheating flames for cutting (the 6 flames that your cutting torch has when the trigger is not depressed). It is also the only thing you should adjust for at the torch when cutting, the only other adjustment made is the PSI of O2 when you pull the trigger - this is set at the regulator on your tank. The cutting process consists of heating the metal with the neutral flame until it's bright, cherry red and then pulling the trigger unleashing a full 25PSI of O2 at the preheated spot and starting your cut. So, the steps are: 1. Adjust your torch so that all 6 'preheat flames' are neutral ala the picture, make sure that your 'lower' O2 valve is all the way open and make the adjustment on the upper. Notice that the blue inner-flame core has a solid edge and the center isn't white or washed out, there should be very little hissing. 2. Put the flames almost into contact with the metal where you intend to start your cut. 3. Allow the metal to preheat until a bright cherry red spot is formed. (should take less that 5 seconds, if not, you need a bigger cutting tip) 4. Pull the trigger and make your cut. It's all about the flame.
Yep. I know about adjusting for a neutral flame. I haven't tried it yet but I reckon it could be the wide open O2 valve and adjust with the top one. I haven't been doing that. Makes sense (i hope) because I've done everything else everyone has suggested. I figured it would be something so basic that nobody bothered to mention it, not for a while anyway. I'll give it a go and report back. Pete
Huh? The closest US standard stock equivelant to 5mm is 0.1875 (3/16"). 22 gauge steel sheet is 0.0299" thick or about 0.76mm. Am I missing something?
Yeah, the O2 valve at the hose has to be wide open so you get a full blast to cut with. Adjust the flame with the valve on the attachment. Somebody else said 5 psi acetyline and 20 psi O2 - thats what I've always used also. Bill
i second, third, forth? the neutral flame thing, i used to have a broken set of regulators and i couldnt get the neutral flame set up right, and it would build up carbon ("slag") like you described. i took a class on gas welding and cutting, and i havent had the problem since.=) go figure. i also got new regulators and tips.
3/16" is 4.5mm. So 5mm is 3/16 and a bit. My snips weren't quite up to it Looks like the O2 setting could be the culprit
PROBLEM SOLVED. I did say it would be something simple and stupid. It took Lolife and Redneck Smooth to take me right back to basics. That was my problem. Very straight forward and stupid. I was trying to make adjustments at both ends. Made some sweet cuts today. Thanks Lolife and R.S. for the help. Thanks to everyone else too. I'll have to get my cylinders refilled tomorrow and just spend my day cutting shit out. Pete
The Jalopy Journal
