Don't feel like the Lone Ranger on this flame cutting deal. You should have seen what my first attempts looked like. The very first thing that I tried to cut was a caliper bracket for a rear end, about 4" x 6" and out of 3/8" plate. I had a piece of plate that was about 18" x 60" and I ended up with the whole thing cut up trying to get 2 pieces that I could even beat out of the skeleton with a hammer. I had no experience with anything like this other than to watch a guy at a local muffler/speed shop cut some header flanges. He wasn't a heck of a lot better than me, but he didn't have to beat on them quite as long. LOL Anyway, let's see if we can't help you with this. To begin with, I probably ought to ask a little about your equipment. You said that you built it and that's great, my machine is homebuilt also. Do you have a variable speed motor on it? Is it a double arm pantograph type or is it an X-Y numeric controlled type? Does it have a magnetic tracing rotor for following the pattern if it is the pantograph type? At this point at least, I am going to assume that you have a double arm pantograph type machine with a variable speed motor and a magnetic tracer. If you don't have this type of unit, it is going to be difficult to achieve satisfactory results without being able to control the travel speed of the cutting very precisely. I know that there was an outfit on the east coast that sold a plan set that said that you could make patterns from plywood and plastic and it used a Ford wiper motor for power. My experience would lead me to believe that it was awfully hard, if not impossible, to get the quality of cut that you are wanting with this type of unit. The first factor that I think is important is that you want to only use the least amount of heat that you can to accomplish the job. This is where the pressure adjustment comes into play. Begin with the recommended settings as shown in the charts that were mentioned in the other post. As you get a little more proficient, you might experiment with minor deviations from these setting to fine tune for your equipment. Most people have a tendency to crank up the heat and that is not the best idea. Clean cuts are the result of using the minimum amount of heat necessary and controlling the speed very closely. Clean cutting tips are absolutely necessary and should be cleaned before each cutting session and during the session if it becomes contaminated. Also be careful with the tips as a drop can damage the seat area and make adjustment difficult. As has been previously mentioned, use the correct size tip for the material that you are cutting. Clean material also is very important. Even clean hot rolled plate or bar stock will have a scale layer on it that can be problematic if it is loose on the base material. It will tend to pop and can contaminate tips. Here is how I go about making a cut. I position the part and the pattern so that they align with a minimum amount of material waste. If the part has any inside cuts, I drill a 1/8" hole inside the cut out about ¼" away from the cut edge. This allows me to start the cut on a "raw" edge and it will start much quicker than trying to get enough heat into the plate to pierce it. If you put that much heat into a small area, it will be almost impossible to get it to cut cleanly. I also drill 1/8" holes outside of the part if it is critical that the part doesn't do any creeping as it is being cut. That way it can only move within the "kerf" of the cut. Just a little more guarantee of achieving the accuracy that you are looking for. This will probably sound a little dumb, but always make any inside cuts first, it's kind of hard to make them when the piece is laying on the floor if you cut the outside first. I know, I've done it. O.K., time to light up the torch. Open the acetylene valve and crack the oxygen valve a little also before using the striker to light the torch. That way you will not get the acetylene soot when it lights and that will contaminate the tips a lot of the time. e flame sound kind of like frying bacon. Just a little crackle to it and it should be long and smooth. With a 000 or 00 tip, I can just about put the tip of the flame on the floor. When it's like that you know you're ready to do some cutting! Hold the torch so that it is right on the raw edge of the material, either on the perimeter of the material or the drilled hole and begin preheating the plate. If you have everything properly adjusted, the cut should start within about 5-15 seconds when you hit the blow oxygen. If it takes much longer than that, you need to bump up the heat a little. I hold the tracing rotor pinched between my thumb and first finger and kind of guide it to the edge of the pattern. It should begin to make a clean cut right from the start if you have the speed adjusted correctly. You can tell a lot about the cut by watching the bottom of the plate as the torch proceeds. If the stream of sparks is rather aggressive and shoots out in a very definite line that is fairly close to horizontal, the speed is too fast and will need to be slowed down some. If the dross is kind of falling off in blobs and eratic, you're too slow and it needs to be picked up. An ideal spark pattern is when the material comes off of the plate in a gentle arc that slightly preceeds the direction of the cut. Kind of a nice quiet shower of sparks if you will. The difference from one extreme to the other will be in a pretty narrow speed range. Make the changes very gradually. When you achieve the desired results, the cut will be clean and the cut lines will be vertical and nicely defined. The cut part should fall cleanly out of the skeleton and will have a paper thin layer of scale that will brush off with your hand…after it has cooled! The end of the cut is a bit of hand-eye coordination as you need to cut off the blow oxygen just at the end of the cut. Too soon and the part is still attached to the skeleton and too slow and the part can be nicked by the flame as it falls free. I generally try to start and end my cuts on an outside corner or radius so that I can touch it with a disc sander to hide any puckers that might occur at that point. There are a lot of other little tricks to make the results easier to obtain, but I won't bore everyone with them here now.

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