The Naiad Voyages

Mark Austen

2016.10.01 - Adding a Fillet

Today's first task was to add a fillet to the entire cabin and cockpit structure. This takes time and so I started early before the day had time to warm up. I needed the epoxy to stay cool so that I could get a longer pot life.

The task itself is simple but repetitive and if you don't pay attention to what you are doing you can really mess thing up both literally and metaphorically. The epoxy is mixed with very finely milled wood fibres, so fine that it is a dust and the required consistency is that of peanut butter, stiff and not likely to sag. This is then applied either with an icing bag as a long thin round 'sausage' of epoxy or by using a thin stick to apply it. I tried the bag method but my bag was not stout enough and split so I reverted to the stick method. Once you have some epoxy where you need it you use a rounded flat stick like the stick you get in ice-lollies and ice-creams these days to form the epoxy into a nice smooth curved fillet.

Well, that is the idea. In practice it rarely goes exactly the way you want it. It is important to remember that 'perfection is the enemy of good' as the saying goes, and you should not strive to have a perfect result. If you do try then all you are going to do is waste a lot of epoxy as it cures whilst you are trying to get that 'perfect finish'.

On Naiad, the deck is not only going to be painted but whilst the undercoat is still wet I will be spreading fine sand on it so that when the top coat is applied the result is a rough, non-slip deck. Therefore, there is no point in trying to keep the odd bit of epoxy off the deck as it just does not matter. The deck will be sanded before the paint goes on, so the really rough bits will be smoothed out but there is still no point in being worried about getting stuff on the deck.

The cabin sides, however, are going to be epoxy-coated and then varnished so it is important to remove the thickened epoxy before this is done. In the case of the thickened epoxy, either with wood fibres when making a joint or the filleting blend I used a 3" paint scrapper to immediately remove any epoxy that got onto the sides where I did not want it.

It took 2 hours to complete the job, time for a break.

It is not easy to see the fillet i the light of the workshop, but it is the shiny bit at the join between the side deck and the cabin side.


The after part of the cockpit had a small fillet, only about 1/4" high as the coaming here is only 2" high. There's no point in putting a huge great fillet here, not only wold it be a waste of epoxy but it would look pretty stupid.


Once I'd finished I went around the fillet checking how it looked and found a bump that indicated a bubble of air in the epoxy. I used a piece of wire to open the bubble out and smoothed the edges a bit and I'll fill the hold with epoxy the next time I am mixing some up.