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Hi Tod, I sniped some of my previous thoughts on vertical and overhead welding. HTH *****************************************
Ovehead weldments have a greater tendency to have both slag and porosity inclusions. As an AWS inspector I have seen alot of this and started watching welders during certification tests and found that is from the welder trying to hurry too much as his mindset is the puddle is going to fall if he goes too slow. A overhead weld should be made just like a flat weld with a very slight increase in electrode speed. Vertical up welds are best made with good consentration on the molten puddle. This can best be observed welding in the flat position. The weld puddle will be very shinny and will have some swriling action within the molten puddle. The slag looks dull and lumpy will roll to the back of the weld puddle as the puddle moves forward. As the weld puddle forward speed slows the slag will recombine with molten puddle causing the puddle to splatter and gather inclusions and encase the electrode tip causing the electrode to stick to the base metal. The weld puddle width should be about 2 times the electrode diameter. AWS code calls the maxmium weave bead width of 8 times the electrode diameter in any position as any more width than this will cause slag inclusions because the slag cools too much before the electrode returns to deposit more weld. ************************************************* Vertical up welding is fairly easy to do once you get the hang of it. Electrode angle pays a very important roll, about 5* to 10* down from horizontal, 0* works best sometimes, and you need your head below the rod to see the weld puddle with a close arc length and a slightly faster travel speed. Vertical down welds are allowed by code and are limited to 2" in length on fillet welds but most welds fail when ran verticle down as it's very easy to trap slag with in the molten puddle. I only recomend very experienced welders use vertical down. Learn verticle up first! Now most welders watch the "slag" in the molten puddle and not the molten puddle it's self and that causes the molten puddle to fall or the weld puddle will slump before the welder moves the rod upward. Thats why we teach you to weld flat first so you can reconize the weld puddle from the slag. If you can see the difference in the weld puddle and the slag, then do not let the slag take your attenion away from the motlen puddle in the vertical position like it does to most weldors. A vertical weave bead is made by starting a weld puddle then moving horzontial, 8 rod diameters max, then pause slightly to deposit more weld, move up 1/2 rod diameter, then back to the starting point. The horizontal move should be fairly fast so if the weld slumps in the center then your moving too slow. If the ends are under cut then your not pausing long enough at the corners. Take a stratch awl making two vertical lines will help you keep the weld straight and uniform width. The 8 times the rod diameter maximum is so the slag does not cool before you return to deposit more metal. My method of teaching is to have the welder try to move too fast, too slow, long arc length, short arc length, rod angle at 45*, at 5*, too many amps, too low of amps, etc: and pay close attention to the changes each makes in the weld. I reverse teach, "what makes a bad weld". If you know what causes a bad weld then you will know how to correct it when you make that mistake. This is also where your plastic welding lens will fail you the most. You now have two weld puddles due to the distortion of the plastic lens. Which one is the true weld puddle? Use only a all glass lens. T_Bone
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