I've been using the Stits / Poly Fiber products for filling and priming, namely
the SuperFil and the SmoothPrime "pinhole killer", and the EP-420
primer/sealer...have
just missed making a serious mistake...and thought it was worth my time
to share my experience.
I've found all the products very easy to work with and satisfying to bring to
the
desired level of smoothness...particularly the hi-build SmoothPrime, using
a 3 foot sanding board starting at 220 grit before going up to 320 paper. I've
been particularly prideful for doing my entire airframe w/ only 2 gallons.
And that hi-build SmoothPirme is REALLY heavy stuff...so w/ weight always a
concern,
i was pretty aggressive with the sanding as I strove to first, achieve as
straight and true a (wing) surface as I could, and second, to make sure that
as much as possible of the weight of all that SmoothPrime ended up in the
canister
of the shop vac. It certainly didn't bother me that my wing surfaces, as
smooth and true as they may be, got pretty blotchy w/ ALL the SmoothPrime
removed
in some areas where great areas of blue SuperFil became visable. It didn't
bother me because I knew I would be applying the white EP-420 epoxy primer
on top...and all of this time, I believed that the EP-420 would provide the
necessary
UV protection. WRONG !!
The EP-420, 2 part epoxy primer DOES NOT provide any UV protection...I had
misread
or misremembered...and only learned by chance during a conversation on a
related matter w/ a Stits tech person.
So with that Stits product line, it is the SmoothPrime which provides the UV
protection...not
the EP-420 primer/sealer! And I'll be working on a 3rd gallon...rolling
on 3 coats...sanding it smooth down to 400 grit...but stopping while
I still have a white airplane...before applying the EP-420 primer/sealer.
Fred
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