Model III and IV Owners shipped after 4/1/1991 -
FROM: Denney Aerocraft Company
several months now 1 pint of cotton fox (WCF-39) has been a standard
part of the wing kit. It is used as a thickening agent for the epoxy
structural adhesive, (FSA-2A and 2B).
recently discovered that we have mistakenly sent to several Kitfox™
builders have received fiberglass micro balloons instead of cotton flox.
we have used micro balloons with structural epoxy, we have never used it
for wing construction. We don’t know whether the hardened epoxy with
micro balloons will have the same properties as that with cotton fox.
are conducting a series of tests to compare these properties. In the
meantime, we recommend you check your WCF-39 to determine whether it is
actually cotton fox or fiberglass micro balloons. Both materials are
white, but they have very different textures. The micro balloons are
more fluid, the cotton fox has a texture like lint. The fox will not
“flow” at all, and separates into particles that resemble various
sizes of pellets. Fiberglass micro balloons look like powdered sugar.
When you handle them they may make you sneeze and cough.
have micro balloons, do not use them in your structural epoxy. Call or
write our Customer Service department and we will send cotton fox to
you have already used micro balloons in your wing construction, we
recommend you do not cover the wing or proceed with construction until
we have concluded our tests. We will advise you as soon as possible of
the results of these tests. Let us know if you have already built your
wings and used fiberglass micro balloons as the stiffening agent so we
can send these results to you, along with further recommendations if
you need assistance in any way, please call customer service. Before
returning any items to Denney Aerocraft
Co. please obtain a Return Goods Authorization (RMA) number from