Technical data

13773-001
51-20
Page 1130 Nov 2000
F. Cutting Reinforcements
(1) Templates
After the extent of damage is determined and the area is prepared, repair ply templates should
be made. A template is used to assist in cutting the correct shape and size of glass-fabric. A
template should be made for each layer (ply) of composite repair. Clear plastic sheet is com-
monly used for this purpose, however release film may be used instead of clear plastic.
(a) Remove surface coats from the surrounding area of laminate damage. Remove all paint,
primer, and body filler from the perimeter of the damage by hand or by using a multi-action
sander. Expose at least a 1.5-inch to 2.0-inch border of undamaged laminate around the
repair area.
(b) Construct template as follows; tape plastic sheet over damaged area. Draw line on plastic
sheet off-setting the inside edge (first repair ply, smallest) of damage by 1.0-inch mini-
mum. This is the dimension of the first repair ply.
Note: The first template manufactured must be a minimum of 1.0-inch larger than
the damage. Each remaining template must be 0.5-inch to 1.0-inch larger
than the previous template.
(c) Tape a new plastic sheet over the previous plastic sheet and draw a line (larger in radius)
off-setting the previous line drawn by 0.5-inch to 1.0-inch on the new plastic sheet (first
repair ply, smallest). This is the dimension of the next repair ply. Repeat this step on a new
plastic sheet for each subsequent repair ply.
(d) Determine fiber orientation for each ply. Label template with fiber orientation (0° or 45°).
(Refer to 51-20), (See Figure 51-202) Repeat this step for each repair ply.
(e) Properly orientate and cut glass-fabric to the same dimension and direction as traced onto
each plastic sheet.
(2) Cutting Repair Plies
Glass-fiber cloth can be cut with clean sharp scissors or razor knife. Dull tools will catch and pull
fibers, distorting the fabric. The cloth is very drapable, it is easy to pull out of shape during cut-
ting and handling. Exercise caution when cutting and handling the glass-fiber cloth to maintain
fiber orientation. Clean all tools with solvent and dry thoroughly before using.
CAUTION: Never handle glass-fabric materials with bare hands, use clean cotton or rubber
gloves. If fabric becomes contaminated from oily hands or any other source, the
fabric must be discarded. Because contaminated fabric will not bond properly.
Always store glass-fabric materials in clean and sealed containers. Keep glass-
fabric out of direct sunlight.
It is difficult to determine the fiber orientation of a piece of cloth once the factory
edge has been removed. If the factory edge is unknown the fabric must be dis-
carded. Using fabric without knowing the ply orientation can cause a weak repair.
Position template in the required orientation. Hold template against the fabric
when cutting. This will reduce the chance of distorting the material. The template
should be kept with the repair ply.
(a) Position the glass-fiber cloth on a contaminate free cutting surface.
(b) Orientate each template onto the cloth. Cut cloth around template with a sharp, contami-
nate free tool. Keep each template and repair ply properly orientated.