On 29th
March 2017 my wife and I drove the 570 mile round trip to collect the machine
cut plywood sheets from Jordan Boats near Taunton in Somerset. Although a lot
of time is saved by opting for CNC cutting,
there is still a considerable amount of time required to release the components
from the sheets with a saw, plane the projecting tabs of plywood flush with the
surrounding profile and clean and fair all the edges. Buying the pre-cut plywood
sheets in this manner if referred to as the ‘kit option’, although I would
suggest that this is a slight exaggeration. A kit suggests that you might
simply assemble the parts which is not the case; a lot of work is still
required to produce the finished components ready for assembly.
I
experienced problems with some parts not lining up correctly. Alec Jordan
had made some errors when programming the files which revealed itself as misalignment on two transverse bulkheads. I contacted him to outline the
problems and to his credit he immediately responded, took full responsibility
and re-supplied the parts without delay.
I would therefore not hesitate to recommend his services to others due
to his prompt action in rectifying the mistakes.
Loading up the
29no CNC cut plywood sheets at Jordan Boats
Components
released, cleaned and faired. I rolled the jig over and used the bottom as a
bench for assembling and gluing. This
proved particularly useful for the planking which requires a long flat surface.
I dry assembled all parts before gluing to be certain everything fitted and
lined up correctly. The planking was glued up in pairs with polythene strips
laid between the layers to prevent sticking to surrounding surfaces. A batten
was screwed down over the joint to provide a clamped flat joint.
All jointed surfaces were first wetted out, including large surface area laminated
components and then allowed them to soak. I then applied a further coat of epoxy
mixed with Silica to both surfaces, rolled to achieve an even coating before
assembling with stainless steel screws where appropriate then clamps. All screw heads were counter sunk,
filled with epoxy filler and sanded off flat as the work progressed. I figured
it would be much easier to carry out as much fairing as possible whilst the
parts were in a flat level plane. I also rounded all exposed corners within the
boat to provide a user friendly surface and minimise the risk of injury in the
unfortunate case of a fall.
The centre board case has a 20mm diameter hole
to carry the spindle of the centre board. I had concern’s that this was a lot
to ask of the plywood with the potential for wear and the possibility of water
ingress into the inaccessible case. I considered the idea of inserting a brass
bush for the spindle to rotate in; however I wondered if the two different
metals may react and corrode in sea water, I therefore contacted the architect
to express my concern. He agreed that may be a problem and offered the
following solution; bore out the plywood to around 40 – 50 mm diameter and fill
with epoxy mixed
with fibres, drill this out to accept the spindle. I thought this an excellent
idea and devised the following method.
To
accurately maintain the centre of the 20mm spindle bore, I screwed a sacrificial
piece of board to the outsides of the case with a layer of polythene trapped
between. I then passed a 20mm auger through the pre-drilled holes in the
plywood case and drilled into the board. After marking the position I removed
the sacrificial boards and opened up the holes in the case to around 45mm using
a hole saw. I considered the horizontal score marks made by the saw would
provide a good key for the epoxy. I then replaced the sacrificial board and
polythene separator exactly to the marks and inserted a short length of 20mm
plastic conduit wrapped in plastic packing tape to achieve a clearance dimension
of 21mm diameter. After wetting out and leaving to soak, I filled the remaining
void with epoxy mixed with micro fibres. Two days later when fully hardened, I
removed the board and extracted the conduit to leave a perfect hole exactly in
the original position. I further reinforced this by sheathing over in 300gsm
twill woven glass fabric soaked through with a thick layer of epoxy, providing
a tough water tight seal to all surfaces within the centre board compartment. When
assembling the back bone a further layer of epoxy was applied and rolled out to
provide an even coating.
The completed epoxy spindle bearing sheathed over in
300 gsm woven glass fabric. When set, I cut through the fabric and trimmed it
back to the edges of the hole. A further coat of epoxy was applied before the
closing of the centre board case
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