Fibre Glassing The Hull

It has been a long time since the last post with not much to take photos of or write about. In between lots of filling and sanding I have been traveling and sailing.

Here's a photo of the hull after I finally decided that it was fair and smooth enough. The patches of filler are where the hull had hollow areas; I'm not sure how these came about but suspect that the first layer of strips was not well enough supported by the building frame. The hollows occurred on both sides of the hull in the same places. There is a substantial fillet in the corner between the hull and the skeg to make the cloth go round the corner.

I decided to use 200 GSM cloth on the basis that the hull (15mm thick) is strong enough without the cloth and so the cloth is to provide some abrasion resistance and a stable surface for the paint. The next step was to overcome my apprehension about the process of applying the cloth and resin. After advice from other members of the Wooden Boat Association (thanks guys) and from Ross Lillistone of Bayside Wooden Boats (thanks Ross) I assembled all the materials and tools and finally got stuck into it (quite literally, resin everywhere!).

Here is the workbench with the necessary stuff. Across the front from left to right: Stanley knife, calculator and scales (I measured resin and hardener by weight - pour resin (250 to 280 grams) into one of the larger white cups, multiply it's weight by 1.44 and then add hardener up to that number), in front of the white container are 100mm squares of 1.5mm thick balsa wood to use as squeegees, the container of brown hardener is next and in the box under the green cloth is the resin with a 60 watt bulb to warm it up slightly. The tilted ice cream container holds some white vinegar for had washing. Hard to see are some cheap paint brushes, foam roller covers, and scissors. I tried mixing the resin with a stirrer in the battery drill (wing nut on a piece of threaded rod) but this was slower and not as effective as a flat plywood paddle.

Here is the cloth draped over the first side of the hull; I decided to cover the two sides on separate days to spread the work out. The cloth tried to slide off so I tacked it in place along the keel with masking tape. The plywood strip is pinned in place and holds the cloth up towards the corner at the skeg. The cloth with be overlapped at the stern; along the top of the keel I felt the overlap wasn't necessary because the rest of the keel and outer stem will be fixed over it.

First coat of resin applied. The surface is slightly matt at this stage because the weave of the cloth isn't completely full. This coat took a little over 2 hours to apply taking care that the cloth was stuck down with no excess resin underneath causing it to float.

Second coat applied starting when the first coat was still tacky but not soft (the waiting was the hard part). The surface is now more shiny. This coat was quicker to apply because it needed less resin (less mixing time) and it could just be squeegeed on, trying to keep it even and free of runs.

After a long wait because the temperature dropped in the afternoon the third coat went on. The resin was thickened slightly for this coat. I tried for a consistence like tomato sauce but I think my sauce was too runny; after the first batch I added more filler but maybe still not enough.

This coat took a little over 2 hours to apply. I trimmed the skirt around the sheer line with the Stanley knife, by this time the first coat was firm enough to allow the cloth to be cut easily. Cutting the excess cloth away where it wrapped around the stem was easier with a scalpel blade (much sharper).

The next morning the surface looked awful with runs and sags where my too runny resin had moved. This was expected and the lumps and bumps will be sanded away. No photos of the bumps!

Three days later (17/7/2016) and I have just finished the other side. Less stressful than the first side because I knew what to expect. For the third coat I made the resin a bit thicker but there will still be runs. As it gets thicker I find it is more difficult to spread in a smooth coat. I suppose that after a few more boats I will this sorted out!