10. Applying west system and peel ply to fibreglass

Now that the main hull was fully planked up with DuraKore it really was looking like a boat, however I had to remind myself that this was only the core of the hull, the core between the fibre glass laminates on the inside and outside of the hull.
The next job was to remove the many hundreds of those screws that were put in to hold the DuraKore in place until the thickened epoxy resin cured, and every one of those hoes needed to be filled. Prior to laying any fibre glass and resin onto the hull, I sanded off very carefully the excess resin all over the hull taking care not to sand away any of the marine hardwood Gaboon veneers, as you will remember they are only 1.5mm thick.
I hate sanding, and fortunately after approximately 6 Duracore planks were edge glued and screwed to the mould frames, I went over the joints with a scraper removing excess resin before it hardened saving a lot of hot sweaty sanding time and cost of sand paper.
The next job was so welcomed, as I needed something different from edge gluing DuraKore strips to a mould.
The next job was to lay up the first layer of Fibre glass which consisted of only 1 layer of 270gm bi-directional glass fibre.
Fibre glass is supplied in several weave patterns. bi-directional as its name suggests, 50 percent of its fibres running the length of the cloth on the roll, and the other 50 percent across the width of the cloth, and its designed strength is in both directions. There are also some other fibres running across the width of the cloth are only there to hold the glass fibres together as a flat cloth so that we as the boat builder can easily lay the fibre onto the hull, without the fibres parting in every direction as the resin is rolled in. The weight 270gm is its weight per square meter, and reasonably light cloth, as DuraKore contributes so much to the strength of the hull in the fore and aft direction no glass fibre is required in that direction.

The Bidirectional glass was laid up 45 degrees to the planking, other words the fibres ran across the strip planking joints at 45 degrees to the joint. This laminate transfers the loads along the fibres in those directions that the DuraKore Gaboon hardwood fibres are not able to as they run the length of the hull, just as internal diagonal bracing does in the old timber constructed hulls.
I started approximately halfway down the Hull and simply draped a length of the cloth over the hull to the opposite edge at 45 degrees, and cut off the surplus close to the edges of the hull.

I mixed small amounts of Epoxy resin at first, about 5 pumps each of West System Resin and hardener and rolled that on with a standard paint roller used for oil based paints.
The temptation is to mix larger amounts, to save time mixing the stuff all day, but this resin generates heat once the hardener is added and stirred, and with larger volumes of epoxy resin in the container the greater the reaction and shorter the pot life. Before you know what has happened your hand is hot and the epoxy is hardening in the pot, as well as melting the plastic. I kid you not!

It is important not to roll too hard or too much as the glass fibres are reasonably brittle and can break therefore affecting the final strength of the laminate. It does not take too long to work out the best method to wet out the cloth. Some areas I found it easier to lift up the dry glass and wet out the duracore, then carefully lay the dry cloth over the wet hull while rolling a wet roller on top to spread the cloth wetting the glass onto the wet hull ensuring that there was no air trapped under the glass.
It may sound difficult but it certainly is not, it is just technique and practice and does not take too long before you are covering larger area’s fairly fast. You need to work reasonably quickly with the pot life in mind.

I only started to use release fabric once I started fibreglasing the inside of the main hull, up until them I did not know about it. After a couple of cloths had been laid onto the hull I laid a release fabric called Peel Ply, which really just looks and feels like nylon spinnaker cloth. It is not necessary but I recomend using it as it really improves the cured finish texture and helps to remove excess resin from the layup, when it is ripped off once the epoxy has cured. The best benefit for me was that as the release fabric was ripped off it also removed the bi products, waxes etc formed during the curing process that would otherwise need to be removed washing or by light sanding etc, which is extremely important before any other epoxy resin work or bond joints are made over top of cured epoxy surface. Sanding is not really recomended as the wax blocks up the sandpaper ver quickly leaving the sander ineffective.

This process was continued until the main hull was finished. I did all this work without any help, in fact the only help I asked for was when I needed to lift the deck, or out rigger hulls into a new position etc. Apart from that it is possible to build a yacht this size by yourself.

9. West System Epoxy Resin for my Grainger MTB920 Trimaran

The Epoxy resin that I chose to use was 105 West System manufactured by Gougeon Brothers, Inc.
I really like using West system as I learnt to use it for many different jobs on my Trimaran.

Not only was it used on the obvious fibre glassing work, but thickened up with additive powders it was used to bond in the bulkheads and furniture, as well as the final water barrier protection before applying the 2 pot undercoat and top coat paints.
I also fitted all my hardware fittings without having to use nuts and washers, as all that was required was too drill an oversized blind hole, fill it with a thickened epoxy resin mixture, place the fitting such as a winch over the filled holes, and drop the stainless bolts through the mounting holes into the epoxy filled holes. It is a superior methodof attachment to the conventional nut and bolt technology.This proved to be a fantantastic solution to preventing water leaking down through bolts into the hull or inside the hull etc. If used on wooden boats it would also prevent ingression of water rotting timbers etc.

The resin is a clear, light-amber, low viscosity epoxy that can be cured in a wide temperature range to yield high strength, rigid solid bond which has excellent cohesive properties and also is an outstanding moisture barrier.
There are two types of hardeners formulated for use with 105 resin.
205 and 206 hardeners require 5 part resin to 1 part hardener mixing ratio. 207 and 209 hardeners require a 3 to 1 ratio, and solid state 6 to 8 hours.
205 hardener is mostly used for general bonding, barrier coating and fabric application. It was also formulated to cure at lower temperatures and to produce a rapid cure that develops its physical properties at room temperatures. Its pot life is 9 to 12 minutes at 22 degrees C, and cures to solid state 9 to 12 hours.
The 206 hardener is a slower hardener and provides a longer working time especially when working in climates of higher temperatures. I tended to use mostly this hardener as its pot life is 20 to 25 minutes at 22 degrees C.
Special pumps can be purchased to dispense the correct amount of resin per 1 full stroke of the resin pump, and the correct amount of hardener per 1 full stroke of the hardener pump.Mixing containers can be bought, however being a scrooge I preferred to put my money into the boat and not the rubbish bin. I had my wife and our neighbours saving plastic milk bottles and other suitable containers for me. My supply of milk bottles was insane at times. I cut the tops off those to make suitable containers.

2. The Trimaran boat build shed

It was autumn and the he first job build a shed, using the cold months of winter to get the mould frames set up so that I could start using epoxy resin and fibreglass to build the boat when the seasons were warm enough to cure the resin. I planned the project around the seasons, so that I always had something that could be done. Progress could not be prevented in my plan.
We moved to Roxburgh, about 1-1/2” hours from Queenstown in the South Island of New Zealand during the summer December 1989. A lovely little town on the side of a river between two large ranges.
It was a country town, with 3000 people on the side of the Clutha River, and a 320 megawatt power station where I worked as an area operator in 1990.
During the summer the temperature can get into the high 30 degree Celsius. The following winter was the coldest on record since the second world war at a low of minus 28 degrees and never got above minus 5 for approximately 7 seven weeks.
So I definitely required a shed!!
I begged and borrowed from some locals for corrugated roofing iron, and only had to buy some 100mm x 100mm x 6M posts and battens for the roof. Begging is something you become good at as a home yacht builder.
While the locals spent their winter days inside next to the roaring fires, I was seen outside building my boat shed. My ears, nose and hands were constantly cold. I reckon they must have thought I was madly insane, they were correct. Everything was constantly white because of the cold, including the coal pile.
Once the shed was built, I had to build a strong back, to support the mould.
This is a solid frame or platform on which the temporary frames and the male mould for the main hull was to be built. The timber for this frame was 200mm x 50mm non treated pine. I concreted stumps into the ground, to provide a solid base that would not move, and built the strong back onto the stumps. This can be seen in the photo of the shed.
The most important thing I learnt from very good tradesmen when serving my time as an apprentice Fitter turner Machinist is that if you start off rough, the job will finish rough. No matter what you try and do later with a rough job it will always finish as a compromise, so always start off with as perfect a job as you can and your boat will look like the panels on a brand new car. No humps or hollows, and minimal filler.
I developed excellent skills as an apprentice and take pride in whatever I do.
I set up the strong back dead level in every direction. This was to be the birth of my Trimaran project.