The latest revision of Mil 13949 is Mil-S-13949H and contains NO requirement for a water mark. (my advance copy carries the date of 24 December, 1992) Hopefully, someone with a final version of this spec. will respond to the water mark question. I believe the water mark is no longer required. Fred J. Paul, Sr. Process Engineer PCB Operations, FLUKE CORPORATION direct: 206 356-5734 fax: 206 356-6070 [log in to unmask] On Tue, 7 May 1996 06:39:48 -0700 [log in to unmask] wrote: > From: [log in to unmask]> Date: Tue, 7 May 1996 06:39:48 -0700 > Subject: Re: Water Mark > To: [log in to unmask] > > Ok..... I'll answer my own question. After a little research, I discovered > the following. My supplier lead me to believe that these specs had been > recently revised. They were wrong. > > First - MIL-P-13949 F, paragraph 3.8 included a requirement for a water mark. > Rev G (released in 1987) omitted the requirement in paragraph 3.8. > > Third - IPC-L -115 B, requirements are word for word from paragraph 3.8 of > MIL-P-13949 G > >