Fibreglassing.

It's been a frustrating few weeks since the last post finishing the sanding process and getting ready to fibreglass the outside of the hull and deck. In the last post I had sanded the whole hull twith 60 grit paper to level the surface out. The next step would be 80 grit on the randome orbital sander and longboard. I wanted a soft pad for the random orbital sander and it took a while to find a source. I bought the last two in stock, 15mm thick, 150mm diameter with no holes. My sander is 125mm so I had to cut some off and punch some holes in the pad. Here's a photo of the result, looks quite good.

After les than 2 hours sanding with the 60 grit paper and being careful when chnging to a new sheet of paper the pad delaminated! Some discussion with the supplier about this and they agreed to replace the pad - but I had bought the last two in stock so I'm waiting! I glued it back together with spray on contact cemeent and it is holding together.

I wanted to collect some of the sanding dust and so bought a small cyclone and mounted it on a plastic bucket. I looked quite good and worked well but the vacuum was too much for the bucket which collapsed!

I tried various plastic buckets but the all failed. Eventually I bought a heavy duty steel bucket and mad a wooden lid. This withstands the vacuum and collects the dust but needs more work to tidy it up.

While waiting for things to arrived by post I started working on the seat. It is laminated from shaped pieces glued together to make a blank. Here it is before any finishing is done on it.

With the outside sanded to 120 grit several cracks between strips needed to be filled. there were a number of fine cracks which will fill with epoxy and not be noticeable. Here's a wider one.

Filling the narrow crack with wood would be difficult. Filling it with bog would show up as clearly as the crack/ The solution (thanks Nick Schade) is to make the crack into a wider V shaped groove and glue astrip of matching timber into the groove.

Cutting a strip of western red cedar 3mm square was a bit of a challenge but I did it and here it is glued into place with the excess planed off. After sanding it looked even better.

The tools for doing this are: veining gouge on the left, Japanese rasp centre and coarse square file on the right. The filler strip was glued in with CA glue and accelerator.

Sanded to 120 grit the surface looked OK but when sprayed with water to raise the grain some PVA glue squeeze out could be seen. The PVA dries clear and is hard to see and, because it has been sanded flat, your fingers don't feel it. Here some PVA on the edge of a strip which is slightly lower than its neighbour.  A freshly sharpened block plane  cleaned these up

Once satisfied with the surface I removed the two halves of the hull from the building frame, very carefully because they feel like eggshells and wouold be easily damaged.

I took the building frame apart and divided the frames between two strongbacks, half the frames on each. This photo shows one strongback with half the frames in place.

The next photo shows the two strongbacks withe the top and bottom halves in place. The shells are tacked to the frames with hot melt glue.

With the halves ready for fibreglass the weather took a downward turn as Brisbane headed into winter. we are having maximum temperatures around 25C and the isn't reached until mid afternoon. Not really warm enough for fibreglassing. My workshop is a metal shed and attempts to warm it up with electric heaters failed completely. One 2kW electric fan heater had no effect; two of them tripped the breaker! In the end I bought a small industrial gas heater which puts out 15kW. It was cheap and has no temperature control - just on of off! In half an hour it raises the temperature in my shed up to the high 20s and the resin is happy! I just have to be careful what it is pointed at.

Two days later and the fibreglassing is done. My intention was to do it all in one day but the shopping expedition to buy the yellow heater above delayed me enough for common sense to prevail. over the rest of the first day I put the cloth on both halves and wet out the bottom half (hull). When this had dried to the just tacky stage I squeegeed another thin coat on. I gauge the just tacky stage with a cotton bud; if fibres are pulled away from the ball the surface is ready, if no fibres are pulled away the surface is still too wet. here's what it looks like.

On the second day I turned on the gas heater early and switched on the light bulb in the esky to warm up the epoxy then went and had breakfast.  An hour later both shed and epoxy were warmed up so I wet out the cloth with a squeegee plus a brush for the small vertical areas at stem and stern. With it all wet out (no white areas and even colour) the excess epoxy was scraped off with the squeegee into a grunge cup. Like the hull a thin fill coat was squeegeed on when the surface was ready. The deck gets a third heavier coat brushed on to build up towards the final finish. After the deck and hull are joined together the hull gets another layer of cloth which overlaps the join  sealing it on the outside. To prevent an excessive thickness of resin along the edge of the hull a strip about 32mm needs to be masked off. Nick Schade uses "flash" tape for this, regular making tape would get stuck to the surface. I didn't know where to get any of this flash tape so I cut some strips of peel ply and laid them along the edge while the first fill coat was still wet. The heavy coat was brushed on and then warmed up with a hot air gun to help level it out and to pop any bubbles. An hour or so later the peel ply was removed.

Time for a beer!