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Construction Notes |
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The
Shoulder
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| The plug
for the shoulder section was made from 1/2" ply
top, bottom and spacers. These were clad with
1/64" birch ply sheeting, glued in place
and filled with P40 to form the required
profile. |
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| The top
& bottom collars were added using high density
insulation batts, sanded to profile and clad in
1/64" birch ply. |
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| The gun
boxes were made up individually from 1/2" CDX
ply and fitted into the shoulder section.
Positioning these boxes was not the easiest
thing in the world - it would have been better
to have built the boxes as one unit and mount it
in the shoulder before cladding. Do you get the
feeling I don't do 'easy'? |
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| P40
filler was used to clad the entire unit to a
thickness of 1/16" and sanded to profile with
600 grit wet & dry. |
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| An MDF
divider was added in order to form a two piece
mould, then the plug was given a coat of G4
sealer and a final sand down before being given
5 or 6 coats of Carnuba wax and buffed to a high
shine ready for laying up. |
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| Two
coats of PVA release agent were applied before
laying up the gelcoat (I was'nt gonna get caught
out again) |
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| Each
mould half was made up by applying a coat of
yellow gelcoat, followed by tissue mat and 4-5
layers of coarse matting, which was taken over
onto the flange for bolting the moulds together
for casting. |
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| The
indented detail trims on the sides of the gun
boxes were added to the inside of the mould
halves prior to laying up the final pieces, due
to the difficulty of separating the moulds from
the plug with the deep undercuts this would have
given them. |
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| The
shoulder mould was given numerous coats of
Carnuba wax prior to being given two coats of
PVA release agent - two coats of black gelcoat
were applied in this case, due to the deep
undercuts and sharp angles involved in the
piece. |
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Following these came the usual layer of tissue
mat and 4-5 layers of coarse matting. Extra
layers were added to the inside of the gun boxes
to give better support for the arm bearings. |
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| After
completion and removal from the mould the gun
box hole positions were marked and drilled out. |
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| The
front indented details was included on the
shoulder plug. If I had had the sense to realise
the problems this would cause on removal from
the moulds from the plug, I would have left it
off and added it to the moulds after bolting
them together. |
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| As
expected, a slight amount of remedial work was
required, but on the whole - it wasn't bad for a
first time amateur. |
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Go to Part 6
- Shoulder Slats & arm boxes |
