Hello all,  Here it goes again, the pouch sealing topic.

I have some questions and findings about this to share.  Recently it
was suggested to use acrylic gloss gel medium to seal pouches.  Well,
after a lot of effort, I have sourced and obtained some.  I painted it
thinly onto some leather and made sample pouches.  I made more pouches
with my old egg white method and some more with normal household
silicone sealer thinned down.

I am testing for stiffness in the leather only since all the methods
seal pretty well.  I do this by gluing them onto pouch wells without
any bleed and inflating/deflating them all simultaneously by means
of tubing and tee connectors.

Now for the question: How should the ideal pouch raise when inflated
very, very slowly?  Should it raise by starting from the middle and
spreading towards the edge, or should it pop up at the edge in one sudden
movement?

This is a difficult one to understand, but the first one, when
inflated, starts raising the middle first and then the leather flexes
up from the middle outwards until it is completely raised.  The second
one just sort of pops from inward to outward in one go and it is not
possible to raise it bit by bit.

The end result is identical but, depending on what I use to seal it,
this property changes.  What is worse, I get different results at
different temperatures.

I am trying to see which pouch moves with the least amount of
pressure by observing which one inflates first.  These are of course
not long-term measurements and I can't say what happens in 10 years
time, but here are the findings so far:

1:  Acrylic gel medium -- Makes pouch inflate from middle outwards and
generally seemed a lot stiffer than others.  The pouch inflates last
and slowest.

2:  Egg white -- Makes pouch inflate in one simple quick pop suddenly
and inflates quite a bit faster than acrylic at above 16 degrees C.
At lower temperatures, it still moves in the same way but the acrylic
is at very similar speeds.

3: Silicone Sealer -- Similar to acrylic but I have to do more tests.

No rubber cement is available here but I have found some liquid latex
and I wonder how well that would work.  I don't know how to thin it
down, though.  Any suggestions will be appreciated.

Silicone grease is also not available locally.  What else should I be
looking out for?

I seem to favour more towards egg again because it was originally used
in German instruments, and it is cheap and readily obtainable in almost
any fridge.  Not to mention that the cat loves the yoke as an extra
snack. :-)

Bernt Damm
Cape Town