I will hopefully get time over December to attempt to build my first plug/female mould.
It will be Claudio’s RG65 Narrow design (he has kindly supplied a modified version (V3b) which is tweaked for my wind conditions and has a more forgiving build tolerance)
What glass weights should I use to cover the plug and then make the female mould?
Does using chopped fibre matt make sense to strengthen the mould or is that not necessary?
Does it make sense to use gelcoat for the female mould?
I’m paranoid that I buy the wrong weight cloth :rolleyes:
° What glass weights should I use to cover the plug and then make the female mould?
1 - the plug should be first covered with epoxy primer and then wet sanding to get the best surface unless is already perfect.
2 - glass-epoxy coverage : 2 layers of 80g/m² followed by wet sanding.
3 - application of wax, according to manufacturer instructions - minimum 5/6 layers ! (Do not use polyurethane products, some are not compatibles with waxes, better check before)
4 - plug ready for moulding
° Does it make sense to use gelcoat for the female mould? :
Yes (local temperature range min. 18°C - max 25°C — relative humidity 50% +/-10% — better check before start)
5 - mould covered with gelcoat better, 2 coats ! always “Wet on Wet” or at list when still sticky (max 1/2 hour) followed by :
6 - glass epoxy lamination : 2 layers with 80g/m² + 3 layers 200g/m² + 2 layers of 300g/m² -
° Does using chopped fibre matt make sense to strengthen the mould or is that not necessary? - Chopped valid for large surfaces, better tissue of the Twill type - The mould shall rest for a week to allow complete polymerisation.
7 - mould ready for hull lamination
8 - 5 to 7 wax coats
9 - 2 layers of 100g/m² or 2 layers of 80g:m² + 1 layer of 50g/m²
10 - demolding after 24 hours min. or according to resin manufacturer .
Andrew,
the weight is the key for every boat when compared with the motional power available.
Given a sail surface and a wind force, the faster boat will be the lighter one without reducing the righting moment.
Weight reduction is achieved with the hull construction technique, but also with the rig construction and sail material choice.
All shall be considered under ‘compromises’ that are the guides of the naval architecture.
For instance, a light sailing boat will move before an heavy one, but will stop also before the heavy one due to their intrinsic inertia.
This is why the first parameter is to decide under which climatic conditions the sail boat is supposed to navigate.
So there are light weather designs as well heavy weather designs.
