Great Planes Learjet 40 Kit - GPMA0439 - Manual (Page 5)

We understand that the caliber of modelers likely to build
the Great Planes Learjet may be rather high You may
already know all about the types of adhesives you like to
use However, due to its easy building features, many new
builders may try their hand at the Great Planes Learjet For
those modelers (experts may read along), we have
provided some explanation about the variety of adhesives
used during construction of a model.
Cyanoacrylate or CA glue has changed the way models
are built more than any other advance in modeling
technology In the good ol' days, model cement like
Ambroid, Duco, Comet and Sigment were the glues of
choice They all had a strong odor that could cause
dizziness, dried slowly (compared to CA) and became
brittle with age CA, on the other hand, is stronger, works
almost instantly and is bottled in three different viscosities
(thicknesses) CA is used for most glue joints, except where
epoxy is specified CA does emit rather strong fumes (some
say it's like tear gas) as it cures, so rule number one is to
work in a well ventilated area. All CA glues work best if
the joints are smooth and fit well.
Accelerator is a liquid chemical that
comes in a spray bottle for use in
speeding up the cure time of all CA
types It should be misted on, not
sprayed heavily on the joint Accelerator
may cause exposed CA to bubble and
sometimes change color If accelerator
is sprayed on too heavily it may weaken
the glue joint, so use it sparingly
A word about CA safety!
After applying CA, to avoid the puff of strong vapors,
don't stand directly over the work All CA glues will bond
skin almost immediately If this should happen, CA
Debonder (available from your hobby dealer) or acetone
fingernail polish remover will dissolve the CA if allowed
to soak into the bond for a few minutes Don't use
vigorous means to separate a skin bond Never, never
point the CA applicator tip toward your face' Be
especially careful when opening a clogged tip In case of
eye contact, flush thoroughly with water, then seek
medical attention, but don't panic. Please, keep CA
(and all other modeling chemicals) out of the reach
of children!
Thin CA is also known simply as CA This
is the adhesive that has revolutionized
model building because it allows you to
assemble the parts first, then apply the
adhesive The thin formulation flows or
"wicks" into the joints and sets almost
instantly, eliminating the need to hold
things together while the glue dries You
will often use Thin CA for the initial bond,
then follow with medium or thick CA for
extra strength, especially when gluing
plywood or hardwood.
CA+ is also known as medium or gap
filling CA CA+ is used for surface
gluing, filling small gaps between poorly
matched parts and for general purpose
applications It cures slower than thin CA,
allowing you to apply a bead to two or
three parts before assembly Curing time
without accelerator is 20-30 seconds.
CA- or thick CA is used when extra
positioning time is needed CA- is a great
gap filler and is also used to make fillets
when a little extra strength is required.
Curing time is about 1-2 minutes.
Epoxy
Great Planes has two epoxy formulations available for the
modeler Both offer exceptional strength and convenient
w o r k i n g times Use epoxy when the joint requires
exceptional strength, such as when installing the firewall,
when joining the wing panels, and when installing wing
hold-down blocks As with most epoxies, you mix equal
parts of resin and hardener, stir well then apply a thin film
to each part Parts should be clamped, pinned, taped or
weighted in place until fully cured Before the epoxy cures,
clean off any excess with a paper towel A word of caution
about mixing epoxy-don't use extra hardener in the
hopes of making the mixture harder or work faster Just
about all epoxies work best with exactly a 50/50 mix When
you increase the amount of hardener, you run the risk of
causing the cured epoxy to become either brittle or
rubbery-neither being as strong as a properly mixed batch.
6-Minute Epoxy is used
for simple, small gluing
a p p l i c a t i o n s w h e r e
elaborate alignment is not
required W o r k i n g time
(before i t s too gooey to
use) is about 5 minutes,
handling time 15 minutes
and it's fully cured in about
1 hour
(Continued on page 8)
5