March/April – glass coating, filling and fairing the Pathfinder hull.
Project blog time : it’s early April 2022 and i’m well along with glass coating the whole of the Pathfinder hull – in fact, as i write, iv’e just got the last runs of glass tape on and iv’e got some of the hull panels covered with filler and already being sanded back. I’m tired because iv’e just had several nights of not much sleep due to a Covid cough plus it’s been cool to warm and dry so iv’e tried to use this time to the maximum and push hard through a tedious stage of the work. This stage feels as though it’s fighting me a bit partially because it’s mostly warm and dry but then most days there’s been a difficult wind to work with – one time this week i just got a plank’s worth of filler on and then a big gust kicked up a back eddy which liberally coated the fresh filler with dust and insects……lucky that most of it comes off again with the sander.
On the bench.
For this post iv’e just got the 2 main jobs to talk about – these being first , the glass coating of the whole hull and secondly the slow work of filling and fairing that should make for a smooth and fair hull once it’s done. Even now i can see a big difference in the appearance of the hull now that the ‘lines’ along the boat are all cleaner curves….that mostly happened when i battened and planed the plank edges and then created a radius over each plank edge to aid me when i glass taped each edge.
John’s plans for the boat say that it’s best to glass coat the underside of the hull – essentially the bottom boards and garboard plank, with 2 layers of glass cloth : some people carry on and glass the entire hull which is what i chose to do. Designer John Welsford says that the boat doesn’t need entirely glass coating for structural strength but glass on the bottom is good for abrasion resistance – usual practice with many builders seems to be glass the underside and then epoxy coat the rest of the hull. I talked about this with the same boatbuilding/laminating friends who advised me on the practical side of the glassfibre work and they said that in their opinion an epoxy coating is much more effective with even a light layer of cloth – in that the end result is much more abrasion resistant and long term waterproof ……it’s just a much more difficult job though and i had to work out my own way of doing it.
My technique was to tape each plank joint with wide (150mm) glass cloth tape, glass the underside with conventional wide cloth as per normal – in my case there are 2 layers of 1 meter wide cloth overlapped, and then to lay a run of the wide tape along each plank and thus covering the already coated plank edge. It seems now like a slow and messy technique when say compared to just laying an entire panel of cloth on one side and carefully establishing it in place – the problem with a wide cloth panel would have been the struggle with multiple plank edges all at the same time : do-able with a team of people who all knew what they were doing but not just me on my own and everything to do. Looking at it now i would say that the glass tape technique has worked but it has taken several days and several stages plus what it leaves on each plank are the ridges of the tape edges and joins which then have to be filled over and faired.
Filling and fairing – the day’s work (every day).
For the last 2 weeks or more now iv’e started my working day with at least an hour of sanding , followed by a long session with brush and vacuum cleaner….and usually finishing the day on the sander too. The filling and fairing job is pretty much as you can see above – hard sand the surface, make up a batch of epoxy resin and Microlight filler and spread that on as fast as possible before it starts to gel : most days now i try and get 2 batches of filler on and as i write iv’e still got several sessions left to do. Tomorrow (Sunday) i need to take a break because one elbow is getting sore and iv’e been going at the various jobs every day for the last 4 weeks……time for a break and i really need to tidy the workshop ; on Monday i need to start planning for the next stages.
Work admin – next jobs.
On Monday, instead of starting the day dusty i’m going to start working on the placement and shape of the 2 skegs – the standard design just has one but my asymmetric board layout allows for a pair and with advice from designer John and the forum i now know roughly where i’m going with that job . In brief at this stage i’m going to make a pair of stack laminated skegs built up from layers of Douglas Fir and completed with a hardwood shoe – Iroko most likely at this point ; each one will be fastened right through the hull so my first job is to measure and draw out on the hull where all the frames and other fasteners are.
It’s a huge surprise to me to be at this stage but iv’e now got to think about bottom finish because i’m going to prime and paint the hull at least as far as the 3rd plank with the hull upisde down and before , hopefully, the final turn over. When i turn the hull back over i’m going to take the building frame out completely because that now needs to become my spar bench plus that i’m going to sit the hull on it’s skegs just on pads – my idea there being to make the hull low and easy to work on. This weekend my admin time will be taken up with studying paint systems , i’m thinking about priming the underside and hull up to the 3rd plank with an epoxy primer but it will have to be one that i can work with in home conditions – with a roller for example because i have no equipment for paint spraying and even with that i may have to completely ‘box’ the shelter in for wind protection.
I’m trying not to do what i usually do which is to get too far ahead of myself mentally and rather just concentrate on the jobs i’m doing right now – the filling and fairing and then bottom completion with skegs and paint…….but…..iv’e really got to start thinking about the rigs soon because within a few weeks i’ll need to order the materials for those as well.
Right now i’m going to have a coffee break in the sun.