So I have a Miller diversion 165 and am currently practicing on some tubes from two old road bikes that were damaged. I have tried doing a slip joing as one of the tubes fits tightly into another and had some halfway decent success. The few miters I have done fit well but when I tried welding them I have trouble controlling a puddle and burn through easily, it seems any less heat I have a hard time getting a puddle and adding filler. I am using the tungsten that came with the welder and am not sure what size filler I should be using on chromoly. Any pointers you experts can lend? Are there any charts that list sizes of filler or tungstens to use? Thanks Al.