Cut out pieces of fibreglass CSM, using the templates. There will be 2 circular disks
for laying flat in the outer mould. You also need enough curved strip pieces to cover
the inside wall of the outer mould in a double thickness of CSM. Overlap 25mm
between pieces.
When you are sure that you have everything to hand, start the resin casting process.
It is a good idea to read through the procedure first, and check that you understand it
all before you start. There are notes on polyester resins in section 8.
The stator casting procedure
Diagram 30 shows the procedure for weighing out the resin and the talcum powder.
The talcum powder is only used for bulk mixes (not thin layers with CSM), to
prevent overheating, and to thicken the mix. Different mixes use different weights -
follow the step by step instructions below. Diagram 31 shows all the parts coming
together.
30. MIXING POLYESTER RESIN
RESIN
CATALYST
3CC
TALCUM
POWDER
200g
200g
400g
Mix resin with catalyst thoroughly but slowly to avoid churning in air bubbles. Add
any talcum powder only after the catalyst is mixed. When the resin is mixed, use it
at once. After a few minutes in the mixing bucket, it will heat up, and begin to set.
Use exactly the right amount of catalyst. Resin casting needs less catalyst than
normal fibreglass work (about half the time). When the workshop is hot, put in less
catalyst. Casting thick layers of resin, put in less catalyst. If in doubt, make some
trial mixes of resin, to find out the correct amount of catalyst.
If there is no PVA 'release agent', then take care not to wipe the polish off the mould
with brush strokes. Apply the resin with a 'prodding' action.
PMG manual
page 28
June 2001