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 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 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!
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.
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.
