I agree with all and am looking into purchasing some Axcess units for semi-auto applications as well. My point is that the RMD/STT is not the best solution for all GMAW applications as pitched by both lincoln and Miller sales reps. For pipe with inconsistant root openings the RMD is excellent(verses traditional short arc) on the root pass. I should mention also that the powerwave 455 is an excellent power source for the other GMAW transfers, just that in my experience with the both the STT and RMD, the RMD operates closer to what the manufacturer promisses.
Lawrence,
I agree with everything you are saying. No exceptions. But someone looking at this post for general info may misinterpret some of the our suggestions. Many less experienced welders feel that GMAW is easy and not as reliable. I work for a public utility and we provide Gas/Electric services to about 19 million paying residential customers in additional to major commercial ones. Our pipelines are welded with conventional short circuit transfer as well as SMAW. The company employeed welders use exclusively GMAW for field applications (construction and repair). For the statement "it will not perform as well with non rotated pipe or uneven fitup.", this statement is true. However, if you read this statement to mean " will not perform WELL" this would be incorrect. Many think that all pipe welding is done with either SMAW, FCAW or GTAW. This company has been using GMAW-S since the late 1960's. GMAW-S consistantly outperforms SMAW in the big picture (time, quality). The welders can use either process in many cases, but, when they fully understand GMAW none ever select SMAW. Some of the more experienced welders have less than one or two repairs a year! Our testing includes all of the NDT processes. RT, UT, ET and on... Each joint requires 3 forms of inspection. 1st -VT, 2nd - RT, UT, or ET, 3rd some form of LT,PT or MT. For transmission lines operating around 1800 psi. they are hydrostatic tested at rating for 6 to 8 hrs. depending on application. I appologize for this dissertation, but find it frustrating that many in the industry do not fully underdstand the operating potential of GMAW, nor the skill required to perform this process as intended. So I am only cautious of degrading the process, discouraging newer welders.