It is important to handle the fibreglass mat with care. The material is
weakened if it is pulled out of shape so the fibres are not perpendicular, or if
there is a discontinuity (such as the fibres are cut). Fibres at the edge of a
piece can also easily be separated from the material, significantly weakening
the edge portion.
Note: It may not be possible to cut the longer 45º weave pieces as one
complete piece, due to the width of the supplied fibre glass sheet. In which
case, these pieces must be cut as two halves, with an overlap to reduce the
weakness. This is not ideal.
Once all the pieces have been cut out, the fibreglass
layers for each size (full length, ¾ length, ½ length and
¼ length) should be weighed. These weights should be
recorded as they are required to calculate the amount of
resin needed. The weight of each blade should be equal
(or within 10% of each other) to ensure that the blades
will be balanced on the rotor.
When all the layers have been cut and the weight of the fibreglass recorded
the layers can be laid out so that they are ready for use in the mould. The
longest pieces are used first, so they should be on the top of the pile. The
weave of the fibreglass should alternate between 90ºand 45º for consecutive
layers. The first layer to be applied to the mould should be a 90º weave, full
length piece.
Etc.
90
45
90
90
45
90 45
Resin
The next step is to prepare the resin mixes. The resin batches are mixed but
the hardener is NOT added. It is best to mix all the components except the
hardener in one pot and measure out the hardener into another small pot
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