Hi all,  As I reply to Troy Taylor's question of attaching pneumatics
with an internal spring...  I have no experience doing this; I have,
however, glued some pneumatics with an internal piece of wood to
prevent it from closing.  I'm not sure if it was necessary with these
pneumatics, and I'm certainly not sure if it was the right thing to do,
I'm not a pro (so please tell me if I did a wrong thing, folks).

I put some thick pieces of felt on top of each other, some firm pieces
that aren't pushed flat when some pressure is added.  These felt pieces
I placed on the open side of the pneumatic (the side opposite of the
hinge side) being careful not put any stress on the new cloth.  Now
I could clamp the pneumatic on.  I don't know how wide your pneumatics
must remain open, but I can figure that if it's a big amount then
clamping can get tricky.

I hope this helps and I hope I'm not giving wrong information here;
if so, please correct me.

Regards from the rainy Netherlands,
Niels Berkers