Blade half manufacture
As shown in the basic design, the blade is comprised of two blade halves, the
windward half and the backward half. This section explains the process of
producing the two blade halves (the next sections explain the process of
joining the two halves and finishing the blade). Each blade half is built up from
16 layers of fibre glass mat. Woven cloth (WC) is used for additional strength
in the direction the forces act on the blades.
This process requires careful preparation beforehand to ensure that the
process of building the blade goes smoothly and quickly. If the resin is allowed
to set while the blade halves are being manufactured then this could result in
a weaker blade due to de-lamination between the two dry layers.
The general process is as follows:
1. Preparation: Cut the layers of fibreglass WC. 16 layers are used in
each half.
2. Preparation: Prepare batches of resin mixture and the corresponding
batches of hardener.
3. Preparation: Wax the mould to ensure easy release.
4. Procedure: Fill the moulds with a layer of resin, then a layer of
fibreglass WC until all 16 layers have been placed. The weave of the
WC must be rotated by 45 degrees between each layer.
5. Procedure: Leave to dry.
At least TWO people are required for this process. A third person would be
useful.
Materials required:
For ONE blade:
Windward face
WC (200gsm)
2.5
Resin 31 441
0.5
Resin 10 03
0.75
Cobalt
5
Styrene Monomer
0.11
Toner
0.05
Lowilite
2
Hardener
17
Dura wax
some
Backward face
2.5
0.75
0.75
10
0.13
0.05
3
20
some
Units
kg
litres
litres
cc
lt
kg
g
cc
Total
5 kg
1.25 l
1.5 l
15 cc
0.25 lt
0.1 kg
5g
40 cc
some
These quantities include any wastage (mainly wastage from cutting out the
WC). This assumes the manufacturer is being careful to not waste materials.
It is recommended to buy slightly more than required in case of any problems.
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