Mike, Based on what we all know as certain "truths" concerning Alloy 42 solder wettability, I'm looking for an alternative to that metal - first. Knowing what we all know concerning the TCE matching characteristics between this alloy and ceramic, are there alternatives, other than Kovar and/or Invar, exhibiting better solderability characteristics as well. I cannot think of any. My application requires receiving typical, pre-tinned (soldered) TCE matching "lids" for ceramic mating to ensure hermetic sealing during and after a reflow process. This is assuming a similar metallization is made to the ceramic that too is solderable. Simply, I don't know the latest and greatest ceramic/metal seal. Moreover, is there one? Earl --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------