I've never heard of 5200 shrinking or cracking and I've been using it for 15 years.

To fasten the Minicell bulkheads I would suggest using 5200 Fast Cure, A cheaper alternative would be Sikaflex 291 or 240.

Jason @ Noah's

> You might want to try one of the polyurethane calks that are now
> available. They seem to stick forever to almost anything and are rated for
> water immersion. The are several brands. PL makes a good one as does MD
> (Macklinberg Duncan). My own opinion is that these are much better and
> easier to use than the traditional 3M stuff. (They also cost half as
> much). My experience with the 3M 5200 is that it shrinks and cracks when
> drying and the joints therefore sometimes fail.