I have attached an excerpt from a presentation I gave at the last MBSI meeting.  I tested several materials for sealing pouch leather.  The three shown in this chart should be of interest to you.  These objective measures were made using the flow meter method advocated by Phil Dayson on several occasions on MMD and at a previous MBSI meeting.

You will notice that eggs do not give a very tight seal but they do maintain the seal over a year.  Rubber cement makes an almost perfect seal at first but, after a few weeks it deteriorates.  Pliobond makes a very good initial seal and the seal maintains for at least a year.

On the other hand, egg whites or rubber cement have a very small effect on flexibility whereas Pliobond makes leather just slightly less flexible.  Silicone seal, another good sealant, is even more rigid.  (PPCo plastic glue also makes a good seal but is very stiff.)

By the way: in practice, don't all pouches puff up the outer edges first and then lift the actuator, which is in the middle?  Look at a plain leather pouch to see what a 'non-intrusive' sealant would do -- but I don't think it matters since the actuator will be the largest contributor to force to resist the pouch inflation.  Try this by putting an actuator  with a small weight on each pouch when you test it.  I'd guess (?) that the least crinkly one would last the longest.

Craig Smith
Fri, 21 Jul 2000 11:07:14 -0400