Composite chainplates

For almost a year we have put off the task of building the composite chainplates for the mast back-stays. The problem has been the 20-30 minute window we have for working with epoxy in our tropical heat. Our laminate schedule for these chainplates was: 1 wrap of 440gsm double-bias 100mm tape (2m long), followed by two lots of 3 wraps of 1000gsm uni-directional 100mm tape, folded in half longitudinally (each 6m long), then another wrap of the double-bias; then another two lots of 3 wraps of the uni-directional, then a final wrap of double-bias, finished of with a wrap of peel-ply. So a total of 30m of glass was to be wet-out and threaded through three 100mm x 20mm slots in less than half an hour – simply not possible. The area could not be boxed off and air-conditioned like the front cockpit.

A burst of cold air has brought record-breaking low temperatures to the Top End over the past couple of days. The day-times have still been too warm to risk racing the epoxy, however it appears the night temperatures are too cold for the plagues of light-attracted insects that normally prevent us working at night-time. Here was our opportunity.

So the night before last we worked on the starboard chainplate, commencing glassing at 1:40am with the temperature at 14.3°C (57.7°F).

We stopped for a cuppa midway, simply because we could.

We finished at 4:49am with the temperature at 15.3°C (59.5°F).

Then last night we worked on the port chainplate, commencing glassing at 12:08am with the temperature at 12.7°C (54.9°F).

We finished (with completely numb fingers) at 2:24am with the temperature at 10.9°C (51.6°F). Tom hadn’t been this cold in 20 years and I hadn’t in 11 years, so it was quite a shock to our systems. But… the feeling of finally having the chainplates glassed is fantastic.