Parachute fabric would maybe be OK as long as it is zero porosity.
Permeable materials are called _filters_, not seals. The other question is
whether you can find long enough pieces without seams, etc. that would make
the job more difficult. Considering the total scope of the job, why don't
you just break down and buy some coated ripstop from an outdoor supplier?
$10-20 worth should easily do the entire job.
-Bob Korves

wrote in message
oups.com...
Dear All,
What is the opinion about using Parachute silk, as material for
Internal "S" sealing ? I have an old parachute, think its material
would be ideal for the aileron sealing of a PIK-20D.
Any comment, god or bad idea ?