When I wrote about this method (11.2.96) it had only been tested on the
tail surfaces where the area accessible to the ski sander was small.
Using the device on the wings needed only a few hours to reduce them to
"local defects only" state. Local defects (depressions which cannot be
sanded out due to nearby thin areas) are left by inadequate thickness of
fill and poor spreading. Most are on the first side which used 0.4
fishing line. 1mm was used for the rest, and having seen how quickly the
sander can remove material, I would go even thicker in future to reduce
the total time.
There are two recommendations gained from this experience. One is to
resist the temptation to speed things up further by pressing on the top.
It is already more than ten times faster than hand sanding and you will
only raise the probability of going to far. If fact you need to use only
one hand and wave the thing across the surface like a hover mower. The
second is not to go too far down towards the leading edge. The local
contact pressure and therefore removal rate goes up extremely rapidly and
you risk getting flats before you have time to see them. (Materials
Ampreg 20, 410 microfiller with 20% fused silica. For sander see
SANDSKI.ZIP in the FTP).
gemin No.83
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