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I
would like to take you through the whole process of refinishing and painting,
putting it into the order you will be performing these tasks.
First always start with carefully and thoroughly cleaning the surface of
your plane. The components of your plane are coated with mold release,
usually a silicon/wax combination, which can cause real adhesion problems with
all the products we will be putting on the surfaces. I suggest you use MEK,
RM 901 or 902. These are the only products I have found that work without
fail. Wet the surface liberally, then wipe with a clean paper towel.
The paper towel absorbs the oils and waxes that have been freed up by the
solvents. Next
scuff up the complete surface with 80 grit sandpaper. This will give the
surface the friction needed to adhere. Most
paint failures are not a result of the products used, but bad surface preparation. All
the areas that are deep enough to need a buildup greater than 3/16" should
be done with micro and epoxy. These areas include fillets around the wing
roots and tail stabilizer, etc. Areas where you will be filling to get a
level fit such as gear doors, canopy to fuselage header, tank to engine cowling,
etc., will also need micro because of the depth of the fill. Micro is
stronger and will not shrink like auto body filler and its 1/3 the weight. Ensure
you get good gaps along with the fills (description of this process will be
forthcoming). I suggest using 36 or 40 grit on the long file board to sand
and shape it. Once you have filled the areas to within 1/16", you
will be doing the final work with skim coat. This is a very fine polyester
putty that will sand out with as fine as 320 grit sandpaper so you will be not
able to tell where the fill begins and ends. To start with, you will be
blocking it out with 80 grit on a sanding block that is appropriate for the size
of the job. Then you can switch to 180 grit to finish it off. Once
you have finished up with the skim coat, you will be ready to switch to the
process of spraying primers and sealers. Sealers are used to do just that,
seal in between the changes from one type of substrate to another and provide
adhesion to both without allowing one to penetrate the other. Sealers
provide some filling for scratches, but mostly in the 320 to 240 grit area, meaning
that it will fill 320 type scratches at best. Anything beyond that will
swell up and show later as the paint finally shrinks up. I
recommend that you apply a light coat to the whole plane to ensure that the
primer sticks to all the different substrates. You can skip this step, but
I don't recommend it. I have never, never had a paint failure with this
method. Now
you can apply a urethane primer surfacer if the surface is done straight enough,
but I myself will apply feather fill (made by Evercoat). This is a
polyester surfacer that is sprayed with a gun. Two wet coats will usually
do. Block this out using the methods you'll find in the Builder's
Page. Once you have gotten the desired results, i.e. straight and no
blemishes, you will be ready to spray on some urethane primers. These
primers pick up where the feather fill leaves off. It will sand down to
320 to 500 grit, which is about ready for color coat. At
this point I would like to recommend that you really take some time to look over
every square inch of the plane with a fine toothed comb. Anything that you
can see will be magnified. It is a misconception that paint covers
anything -- trust me on this one. Take the time to fix everything at this
stage in the process. Once you have the surfaces as good as you want to make them, it's time to start the process of applying color. We
will start with applying a base coat in the main color of the aircraft.
Some painters prefer to apply trim colors first, then taping off the stripes,
and then applying the base. I have no problems either way, however, I
prefer the first method. Make sure after you have the base and stripes
done to your satisfaction, before you clear coat it, you wipe it with a tack rag
over and over at least 4 times. If you leave any dust on the surface, it
will turn to color (like lime Koolaid is white until it gets wet and turns green). Now you will be ready to clear coat, sand, and buff. The processes outlined on this page are described in greater detail elsewhere in our "Builder's Page." |
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Send mail to joe@hensleyaircraft.com with
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