In an article in the LongEZ publication ( Central States Flyer ?) the Ken
Miller suggests, after completion of normal filling, adding 25% filler to the
first coat of primer(called micro-primer), then sand most of this off thus
filling minor scratches and defects and slight low spots. In addition, more
filler can be added to the dregs from the gun and squeegeed into any pinholes
remaining after spraying. Sanding stops when the original filler shows
through in spots. If major low spots show up the micro-primer must be sanded
off completely in the low area and regular filler added before re-spraying. A
coat of normal primer is added once the micro-primer step is complete.
I have seen two EZ's finished with this technique and they were outstanding.
I am unsure whether this is due to the technique or the skill of the finisher.
Is this a common technique? Has anyone used it on their Europa?
This article also suggested use of a "long board" sander as used for
automobile sanding. These are available at auto parts stores and fit a 2 3/4
inch by 17 inch piece of sandpaper which is available by the box at a
reasonable price. This tool works well for initial filler removal, needing
only minor re-touching with a spline afterward.
A couple of EZ drivers visit my project from time to time and provide advice
and a helping hand. One hint which has proved useful when sanding filler is
to lay an aluminum straight edge on the surface and slide it back and forth an
inch or so. This will leave a trace of aluminum on the high spots, helping to
visualize where more sanding is needed. A 48 inch aluminum straight edge as
used for marking drywall works well for this and is also sufficient for
placing the hinges on the rudder & ailerons (contrary to the 50" minimum
called for in the manual).
Applying filler to the LE and to tips I originally found difficult and time
consuming. Using a piece of 10mil aluminum 6-8 inches by 1.5 inches with
corners bent up to provide a grip solved the problem. The aluminum is
flexible enough to follow the contour and stiff enough to spread the filler
smoothly. Bearing down at the outside ends of the tool produces a good
feather edge. I put filler onto the tips and LE first, let it cure, sand it
and feather it in, then apply filler to the complete surface, feathering onto
the previous filler.
In adding filler to a low spot on a previously filled and sanded surface, I
have found that it isn't as difficult as advertised but does require very
careful application. What works for me is to ensure the surface is sanded to
the desired profile everywhere except the low spot. Then apply filler to the
low spot and extend it out at least 2 inches beyond the low spot. Feather the
edges so that 2 inches around the low spot is covered with epoxy and no
filler; feather carefully so there are no thick spots near the edge of the low
spot (now a high spot of wet filler) and allow to cure thoroughly. The epoxy
on the original filler around the low spot will harden this surface so that it
doesn't abrade much while sanding the filler applied to the low spot, allowing
the newly applied filler to be blended in without harming the original. Use
fine grit, 220 or higher.
Trouble starts if a lump of even 3mils is near an area of the original filler
which is unprotected by epoxy; as the new filler is sanded away the edge of
the area will be protected by epoxy and the old filler and the new will be
abraded on either side of this boundary leaving a ridge. Sometimes one can
recover by carefully sanding the lump using fine sandpaper wrapped around a
finger, and sometimes one ends up sanding a new (smaller) low spot in
deliberately and then re-doing it correctly.
Nothing beats sunlight at an acute angle for finding surface defects in the
filler. However, a flashlight works well for finding pinholes, etc. when used
at a glancing angle. I rigged a wall supply to a cheap flashlight to eliminate
the expense of batteries.
The EZ drivers also mentioned a review in the Central States Flyer (?)
critical of the System Three finish, which I had hoped to use. Has anyone on
the Europa net seen this review?
John A044 Newtown, CT
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