Welcome the the forum Ned!
Your English is *very* good for a beginner.. I could understand you perfectly!
"PWT" in this conversation stands for "Percision Welding Technologies" They are a group of consultants and experts on GTAW, PAW and EBW and have probably about 90 years of combined experience doing work with Sciaky equipment. Programming, Process control, set-up, repair, metallurgy, procedure qualification to DOD, Pratt, GE, Rolls Royce, Allyson and more.
They are the best in the world at what they do.
Here is a link to their official contacts and website.
http://www.pwt-online.com/If you contact them, please give them Larry's best regards..