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I Would like to know if we are useing micro to fill
the low spots in the wings or there is something easier or better. I heard
different things on this subject and would like a update before I get to far
along.. New to this site been reading it for the past couple of weeks.
Thanks for your help .
Jeff Paden IVP 70%
Jeff,
Jim White and I used micro on our wings (2x IV-P's). We tried
PolyFibre's "Superfill" first. It was harder to apply evenly, but
easier to sand. We also had lots of small voids that
required re-filling. In the end, we mixed the micro with a bit more
epoxy than normal so it tended to "self level" a bit during cure. I'm
sure this added weight, but resulted in a fairly smooth surface that was
easier to work, and provided a pretty durable surface.
I once asked an experience
builder how one knew when he'd sanded and smoothed the surface enough. His
answer was, "You never sand enough, you just get sick and tired of sanding and
paint it." I have found that to be an accurate statement of
fact.
There are a number of "tricks" to working the surfaces,
but no substitute for serious sanding. We were initially pretty conservative in
applying micro, resulting in several "fills" to level and smooth an area--that
usually turned out to be several times larger than first anticipated. We finally
caught on that it's better to apply lots of micro over an area well larger than
you initially think necessary, then sand the whole area down until you have the
shape desired, and the original skin just starts to come through. If you're not
smooth and flat at that point, reapply micro. Sanding into the skin/structure
when you're "close" is not an answer...
If you live on the east coast and want to stop by the
Manassas Airport (Washington DC suburb), I'd be glad to share what we learned
during building. A better source is one of the "experts" who've finished and
painted a number of Lancairs. Brad Simmons (btsim1@earthlink.net) in Milan, TN is one
such expert, and I can personally recommend him, but there are others. Jim and I
paid Brad to come to the shop and critique our planes when we thought they were
ready for paint. It took us most of a year to correct the problems he found--my
plane looked like a kid's doodle board when he finished--pencil marks
everywhere. When we actually delivered it to Brad a year later for painting, he
said, "fair." I have no illusions about building a show plane, but the finish
has been a humbling experience...
One of the important things we learned from Brad was
the right sanding tools and materials to use. Brad recommended 3M's "gold"
sandpaper for final shaping and finish sanding. It costs about 30% more than
"regular" paper, but outlasts it several times, and does not clog. Available at
any good automotive paint shop. 80 grit for shaping and smoothing; up to 400
grit for "blocking." The second is to use as large a sanding pad/board as you
can for the area. Smaller pads tend to make very small hills and valleys that
show up easily when you add paint. The techniques these guys can pass on go well
beyond a short note like this, but are worth
learning!
Bob
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