Hellouu.
EPO-TEK H77 is hermetic. At least according to their databook:
1.0x10exp-8 cc/sec Helium. Excellent for sealing MCMs and other
packages, they say. Now, why do we laserweld, seamweld or solder metal
cans if you can just use H77? We are old byuers of EPO-TEK and we like
them, but this question has to be ventilated: can a "plastic" really be
that tight against Helium? Or worse...against Hydrogene? A teacher at
one of our universities (chemistry professor) said that 'an organic seal
can never,never and never be hermetic'. Time for revolution? If the MIL
people really accept e.g. H77 as a sealant, I think it's kind of smash!
We can creep out of the cave and drop the club!/
Ingemar Hernefjord
Ericsson Microwave Systems

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