PAINTING THE
PLANE
Painting an airplane is a BIG
job. I knew that before I started,
but after getting a rough estimate $7,000 to $9,000 for what I wanted, I decided
I could do a BIG job. It was
probably a bit bigger than I thought.
This was equivalent of painting at least 3 or 4
cars.
I’ve included here enough
information that it could be helpful to someone embarking on painting their
airplane. If your more interested in just seeing how the finished product
looks, skip the text and enjoy the photos.
Scheme and
Color
The first step to the paint job is
planning a color selection and paint scheme. These things go hand-in-hand since the
choice of colors is influenced by how they are going to be
juxtapositioned.
For me, airplanes bring to mind
the color ‘silver’. With an
all-composite structure; however, colors other than white tend to absorb too
much heat when in direct sunlight, which could lead to weakening of the material
under the most extreme conditions.
So it didn’t take too long pick the metallic silver and the white. The silver would have to be limited to
surfaces that were less exposed; like underneath or, at most vertical. So I began thinking in terms of the
lower half of the fuselage, the gear legs, and perhaps the underside of the
wings, as being metallic silver.
Another factor was that the
Velocity has tinted acrylic windows, and a motif used the factory and others was
to use a trim color around and between the windows that gave the impression of a
large, wrap-around window. It gave
a look that I liked.
Then all that remained was the
choice of accent trim. This was
getting complicated because there were already three colors to deal with, and a
trim would make it four. Overall I
wanted a paint scheme that was a bit of a standout, but at the same time
sophisticated and streamlined. I
had not seen any Velocity with a trim strip down the leading edge of the wing,
and I thought that it would look good, and have the practical benefit of
providing a break between upper and lower surfaces of the wing so the wing would
not have to be turned for application of each coat.
The overall concept for the job had evolved
over the years that it took to build the plane. Now it was time to apply the ideas to
the airframe itself. The first
efforts at this were using sketches on outline drawings of the plane from the
factory. Another helpful idea was
to take some digital photos of the plane, print them, and then use some colored
pencils to apply the paint scheme.
The next step was to use some ¼”
vinyl fine-line tape from the paint supply store to actually put some lines on
airframe. Again, some digital
photos of the rough cut was helpful when coming back
later to carefully put the masking on for painting. I used ¼” or ½” vinyl fine-line tape for
all the edges of the masking. It
stretches to make nice curves, and provides a very good sealed edge for a clean
break of the paint.
Before choosing specific colors a
decision had to be made regarding the type and brand of paint to be used. I’ll skip the discussion of polyurethane
(frequently used on planes and boats) vs acrylic urethane (used on autos). I already knew that there was a Finish Master automotive paint
supply a few miles away that handled all the PPG and 3M products. And I knew other composite plane
builders who had used PPG paints on their planes more than 10 years earlier, and
the finish still looked good.
Decision made - PPG Deltron 2000 DBC for the basecoat and DCU2021
clearcoat.
I went and borrowed a color swatch
book that had all the colors used by GM, Diamler-Chrysler and Ford and began
comparing the many shades of metallic silver and many shades of white, and
metallic whites, trim colors - single stage, 2 stage (base coat/clear coat); on
and on – and selected the colors. The bottom and the two trim colors were
2-stage metallic, so I chose to also use a 2-stage white.
Prep For
Painting
I had done most the necessary filling,
sanding, filler primer, sanding, primer, and more sanding as I progressed in
building the airframe. So things
were in pretty good shape. The
final prep still took some time as I washed everything down with soap and water,
and then wiped down with Prep-Kleen (a solvent cleaner), and then sanded down to
400 grit with a random-orbital sander.
This, of course, exposed some areas that needed some further filling,
priming, sanding, etc. Finally it
was ready for final paint.
Where and With
What
We have nice weather here in So Cal, so I
decided I could do the final paint in my garage with the door open, just like I
did the primers. I put up plastic
sheeting all around to cover the cabinets and work benches, hosed out the floor,
and misted down other surfaces where there was residual
dust.
I borrowed an expensive Apollo HVLP rig from my son in preference to the conventional gun that I had since it supposedly would do a great job with significantly reduce the amount of over-spray.
After consulting with the
customer service guy at Apollo I did some practice panels to adjust the
gun. I found it very difficult to
avoid some ‘orange peel’; especially in the clear coat, but it seemed
satisfactory.
I started by painting the small
parts; ailerons, elevators, hatch cover etc. The first thing I painted was the
underside of the elevators. I could
not get a good coverage and get it on smooth. The Apollo expert insisted that 5-6 psi
cap pressure was plenty high, even though PPG recommended 8-10 psi. After sanding down what I had sprayed, I
broke out the cheap conventional gun and sprayed on a very nice finish (well,
except for having to pick out some gnats, and having some dust nibs). Clearly the conventional gun atomized
the paint to a much finer spray; and, yes; there was considerable overspray
floating around.
I tested the HVLP at about 9 psi
cap pressure, and was able to get a better finish, but also increased the
overspray. Since I had already
purchased a new larger needle and nozzle, and a regulated 2-liter pressure pot
for the HVLP, I decided to proceed with it. If I were doing it all over, I would not
use an Apollo HVLP spray gun for these paints. It cost me many hours of sanding and
buffing (see The Follow-up below) to get the ‘orange peel’ out of the clear
coat, although I would have to have done quite a bit of that anyway to get out
the dust nibs.
Being open to the outside air, and
even some mild wind swirling; there is no way to avoid getting dust on the paint
job. I should have taken the time
to rig some exhaust fans under a partially closed garage door, and provided
filtered inlet air from the windows.
Live and learn.
Doing the
Job
Even without doing a multicolor
paint job there is some amount of masking to do to cover windows, etc. Doing two main colors,
and two trim colors, means spending considerably more time masking than
painting. Basically for each
color sprayed, everything else has to be covered. And because of restricted space, I could
not do the fuselage and the wings at the same time, so it was quite an
undertaking.
With the PPG paint it is typically
2 – 3 coats to get good coverage of base color, and 2 full coats of
clear-coat. The base coat can be
recoated in about 15 minutes, and the clear coat must be put on in less than
about 12 hours of the base coat.
The second coat of clear can be applied 15 – 20 minutes after the
first. It gives a beautiful glossy
finish.
So away I went and masked and
sprayed, and moved parts and masked and sprayed, until the job was done. Well, almost. I had decided to put a ¼” wide dark red
border stripe between the silver and the ‘metallic light almond’ (call it gold)
trim strip. In the initial lay out
of the trim stripe, I used ¼” wide fine-line tape at the bottom. This was left in place during the entire
process, and then removed at the end to expose a strip of the underlying
primer. I bought ¼”
The
Follow-up
Because of the spray equipment I
used, and the environment in which I painted, most of the surfaces had dust nibs
or slight ‘orange peel’ to a degree that was not quite acceptable to me. Most ‘normal’ people thought it already
looked great.
I also did not have enough
lighting during the spray process.
When painting white paint over white primer, and especially putting
clear-coat over anything; the only way to gauge the coverage as you shoot is by
light reflection. So unless you
have lights just about everywhere, you may end up with some areas where the
clear-coat is a bit “dry”, or you may find that you have a ‘run’ or a ‘sag’ caused by applying too heavy a coat. I had 3 or 4 runs; not too bad for the
large amount of area and complex shapes painted.
One of the good features of
automotive paints is the there are alternatives available to make a not-so-good
paint job look great. I guess the
paint manufacturers realize there will be folks like me, even at some body
shops, that need some follow-up help to make their work acceptable. After some advice from others with
experience, these are the steps I went through on all the many surfaces, except
for under the fuselage and under the strakes:
1. Carefully sanded out any runs and
sags with a sanding block, starting with about 400 grit, and working up to 1000
grit, while being very careful not to sand through the clear
coat.
2. Then used 1500 grit 3M Finishing film discs on a 6” DA (dual-action) sander. The discs come 50 to a box. Although having some 1200 grit could
speed things up in some areas, I used only 1500 because I expected to use less
than one box – which turned out to be true. It takes a special “Hook-it II” disc
pad for the DA, and a foam ‘interface pad.
3. The finishing discs leave a dull
surface which needs to be buffed out.
The next step was applying rubbing compound (3M Perfect-it 3000) on a
wool pad. This did not work well on the DA, so it needed a rotary buffer. A rotary buffer can go too far, too fast
(and besides, I didn’t have one) so I found it was doable with a variable speed
electric drill. This step was
probably the most work.
4. The rubbing compound leaves swirl
marks, so the next step is to apply 3M Swirl Marker remover. This worked fine on a white foam pad
with the DA. Pad stiffness, or
cutting ability varies by color – pink, white, black, etc. Probably a pink pad would also work well
with the swirl mark remover.
5. Now there was a good finish that
just needed to be polished and waxed.
I then went over everything with a soft black foam pad on the DA, using
Mcquire’s #2 polish.
6. Last step, again with soft black
pad, I applied a coat of Mcquire’s #3, carnubu wax.
Oh, and don’t forget that after
each of steps 3,4, 5, and 6 the material had to be
wiped off with a soft cloth.
A completely crazy amount of
effort for a paint job, but it will look good for many years. The metallic onyx green around the
windows is beautiful and interesting.
Depending on the angle of lighting, it changes from a
metallic graphite to a metallic green; and overall is a good match for
the tinted plexiglass of the windows.
I also painted the registration numbers on the tip-sails in the same
color.
Nothing left
but some details and the plane is ready to go off to the airport for final
assembly and testing.
