This is the method
proposed by W. D. Gollop in a series of articles he wrote for the
Woodworker magazine in October and November 1968. The cross section
of the sound box, or body, is semicircular. It is made in segments,
like coopered work and there are eleven segments in all.
Timber
| No.
required |
Description |
Long |
Wide |
Thick |
Material |
| 12 |
Strips for
skin |
1100 |
60 |
6 |
Parana or agba |
| 1 |
Base and top |
500 |
500 |
20 |
Blockboard |
| 1 |
Sheet of veneer |
1100 |
300 |
|
Mahogany |
| 1 |
Strip |
1100 |
40 |
|
Formica sheet |
This list gives
12 strips for the skin: only 11 are required, but a spare one may
be needed in case of mishap.
Construction
The author describes
the construction as follows: The work will be facilitated by making
a jig or mould as in Fig. 1.9. This may be made from any timber, screwed
and glued together firmly enough to hold the segments of the soundbox
in place.
Saw and plane the
eleven segments until they fit snugly into the jig. Care must be taken
to ensure that the joints are suitable for rubbed jointing. With a
light coloured wood, the glue line can best be disguised, and the
general appearance of the job enhanced, by the insertion of a contrasting
coloured veneer between the box segments as in
Fig. 1.10. To secure
the segments in position, we suggest driving a thin panel pin through
the segments and into the frames of the jig. Do not drive them in
completely so that when the glue has hardened, the panel pins can
be extracted. Now take the soundbox off the jig, handling it with
great care. Place it open side down on the bench and set out the oblique
base cut, which is 58° in our case. With a coping saw, cut the
base along this line, and replace the sound box into the jig.
Now fit the baseboard
against the bottom of the soundbox, and with a pencil scribe carefully
around the inside. Draw another pencil line 5mm outside, and cut the
base along this second line in order to have enough wood to allow
for the bevel. With a jig saw, cut out the round hole in the base.
Glue the baseboard into position, and secure it with thin panel pins
and proceed in the same manner for the top of the soundbox.
With the jig, baseboard
and top combining to take the strain from the joints, a start can
he made on cleaning up the inside of the box. You can choose at this
stage to leave the interior segmented, which means that only the surplus
glue need be cleaned off, but I favour the idea of having the inside
of the box rounded to match the exterior, as I gather that the rounded
interior is musically more desirable. A curved scraper such as that
produced by "Sandvik" is useful for this interior shaping.
After scraping the interior, cut strips of glass fibre tape 25mm wide,
coat all internal joints with resin, let it gel, and cover all joints
with tape. When the first coat of resin is set apply a second coat,
but without tape this time. This will reinforce the body considerably.
The sound holes
at the back can be marked and cut out at this juncture. After a final
clean up, the side rails can be glued, and two coats of white polish
can be applied to the interior. The body is now ready to receive the
soundboard and to do this, proceed in the same way as described in
Method No. 1.
