Jabiru J450 Constructors Manual
Pre-Paint>Fuselage>Fit cowling
Tuesday, April 6, 2010
112 of 343
Fix the cowl hinges
Sand the bonding surface on each cowl half and the backs of each hinge half to give the flock
a good key to bond to. Clean your Clecoes in Acetone and dry them. Keep the tin of Acetone
handy for later (in fact storing your Clecoes in Acetone can be a good idea because it keeps
them free of oil and other contaminants that could affect an efficient bond).
Mix a batch of resin and coat the bonding surface of each cowl then add some flock to the
remaining resin and then, working on one half of one hinge at a time, apply an even layer of
flock approximately 2mm thick to the hinge and fix the hinge in place with clean Clecoes in
every other hole and then rivet the remaining holes before removing the Clecoes.
Working on one hole at a time, drill a 3/32” hole and use
a 120° countersink bit to carefully countersink the
outside of each rivet hole just enough to allow a
countersunk rivet to sit slightly below the surface of the
cowl (example circled at right) then rivet each hole
before moving on to the next hole.
Drop each Clecoe in the Acetone as you remove it to clean the flock out of it. Clean away as
much flock as possible from around the hinge pin holes, smooth the flock along the other side
of the hinge with a mixing stick and leave the flock to cure overnight.
Next day test fit the hinge pins and remove any remaining flock from the hinges.
In the factory we use a special drill bit (shown above) that is just a standard drill bit welded
onto the end of a spare hinge pin and we clean the hinges through with that (top photo), using
a low drilling speed to prevent any whipping of the long bit. It is important that the hinge pins
fit easily into the hinges without any restrictions.