Appendix; Surface Finishing; Applying The Decals - Multiplex alpha junior unbespannt CONTEST line Instrucciones De Montaje

Appendix

Covering with heat-shrink film is the quickest and most
effective finishing method, and gives outstanding results in
terms of appearance, practicality and durability. The main
MULTIPLEX catalogue includes illustrated instructions on
film covering, and we suggest that you read this text in
conjunction with the instructions included with the film.
Learning how to apply film is not difficult; provided that you
follow the instructions to the letter even your first wing will
be a complete success.
Important:
When covering with iron-on film it is essential to ensure
that the foam core is not overheated, as this can result in
damage (distortion). Some films require a high processing
temperature, and if you are using these types of film you
must take particular care when applying the material.
If you use iron-on film you will obtain good results without
any problems.
Important:
Under the skin of the D-box is a styrofoam core, which
becomes flexible if it reaches a temperature of about
90°C. If overheated the material may distort, and if this
happens the result will be dents and bulges, and there is
nothing you can do to cure it. Naturally we cannot
exchange wing panels which have been damaged in this
way, and we beg your understanding in this respect.
No matter how carefully you sand the surface and remove
every trace of dust with a stiff brush, you cannot remove the
wood's natural grain texture. When you rub the warm film
down with a soft cloth, the material is pressed into the
surface texture, and inevitably follows the microscopic ridges
and grooves of the wood. The result is a less smooth surface
than you might have expected.
This effect can be eliminated in the following way: instead of
the soft cloth, take a thick piece of balsa - similar to a sanding
block - and stretch a piece of stiff fabric over it as follows:
place the block on the fabric, pull the sides up, and staple the
material down on the top of the block. If you now rub the film
down with the smooth side of this block (your hand will be a
comfortable distance from the heat gun) the film will not
follow the tiny grooves in the wood, and you will usually
achieve a highly efficient super-smooth surface, approaching
that of a moulded GRP wing panel.
The ailerons and camber-changing flaps are usually attached
to the wings with hinge tape. However, it is possible to use
the film itself as a hinge. The result can be every bit as good
as a tape hinge. This is only possible if you have followed the
instructions to the letter and produced really sharp, perfectly
straight mating edges on the wing and the control surface.
The top and bottom film must weld together along the pivot
line, and this is only possible if the edges are really sharp.
The first step is to cover the underside of the wing in the usual
way. Apply film to the control surface as well, but do not
finish the job; simply tack down the edges, trim the film to
size, and iron the edges down (i.e. do not use the heat-gun).
Leave excess film at the ends and especially at the front (at
least 5 cm). Pull the excess round the ends, iron it down and
trim it off neatly. You now have a control surface sitting on
the bench, underside film-covered, not yet shrunk, and with
a wide excess of film running along the whole length of the
leading edge.
Place the wing on the bench resting on its leading edge, top
surface facing you; support it in this position. Lay the
projecting film on the wing recess sealing strip and pull it
tight, so that the flaperon hangs down, resting on the top
surface of the wing. Centre the control surface in the recess
and spot-fix the film in place using the tip of the iron. Set the
aileron to neutral (centre) and check the end gaps in the wing
recess. You may find that several attempts are necessary to
obtain identical end gaps. Pull the film taut so that the
aileron is pulled into the correct position against the wing,
and iron the film into place. Cut off the excess film and iron
the edge down permanently. If the control surface is now
brought to the neutral position it should be possible to see
a narrow strip of film between wing and control surface from
above. Fold the control surface onto the top of the wing
again and shrink the film on the underside of the control
surface. This protects the underside of the wing from heat.
Cover the top surface of the wing in the usual way. Trim the
film and iron down the cut edges. Iron the film down firmly
on both sides of the hinge line, then cut through the film on
both sides of the gap from the underside, using a very sharp
knife. The control surface will now be free to move again.
Now comes the most important step: iron down the film 5
mm from the pivot line on the wing and the control surface,
holding the control surface in the extreme "down" position.
After this run the iron over the whole of the pivot line to weld
the bottom film to the top film. Fold the control surface right
up and back, and repeat the process on the underside.
When finishing the job with the heat gun, take a little care
when working close to the control surface to avoid loosening
the film hinge. If it does come loose you will need to repeat
the last stage. When you are finished, the control surface will
be hinged permanently and invisibly to the wing, and will
move freely up and down.
[Fig. 17]

Applying the decals

Cut out the decals and apply them to the model.
There are two convenient methods of applying the individual
transfers included in the decor set, both of which enable you
to position the transfer accurately: the strip method and the
water method.
For smaller items we recommend the strip method: using
sharp scissors cut out the transfer, leaving an even excess
about 1 - 2 mm wide all round. Release the backing paper on
one edge and cut a strip about 5 mm wide from it. Place the
transfer on the model and position it carefully, holding the
exposed strip away from the surface. When you are happy,
press the exposed strip down. Fold the transfer back on itself
so that you can peel off the remaining backing paper starting
from the stuck edge. At the same time rub the transfer down
onto the model with your other hand, starting from the edge
already in place.
For larger transfers the strip method can only be
recommended to the highly skilled modeller; generally
speaking the water method is safer. The surface to be
decorated must be waterproof. Mix a squirt of household
liquid detergent into a bowl of water, and dampen the
surface of the model with the solution. Cut out the transfer as
before, and remove about one third of the backing paper.
Position the transfer carefully, then peel away the remaining
backing paper. Lay the transfer down on the model. You will
find that the water prevents the adhesive sticking, and the
transfer can be moved around to position it accurately. Wipe
out any air bubbles and excess water, working from the
centre of the transfer outwards. The residual moisture will
diffuse away in a day or two, after which the transfer will
adhere in the usual way. In the meantime it is best not to
touch the transfer.
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