Take a look at the answer I've posted a couple of days ago to Mr Glenn Peterson's question titled "Welding Monel Pressure vessel". I've suggested him to get in touch with INCO and Huntington Alloys, who are the manufacturers of Monel. They know the alloy they make better than anybody else.
By the way, do you work for Graham, the well known manufacturer of ejectors and barometric condensers? If so, I'll ask you a favor not difficult to accomplish: to put in the hands of the appropriate person an e-mail I'll send you requiring catalogs and technical literature on those pieces of equipment.
Giovanni S. Crisi
Sao Paulo - Brazil