Thursday, September 3, 2015

The Starling Project - Part 29

The hull has been turned upside down and given a sand with the orbital sander. Using a putty knife I have begun to skim the plywood surface with International Paints 'Epifill' which is an epoxy filler. I did this to fill in the grain of the plywood, still apparent even after a good sand.

The second photo shows the epoxy filler applied to the whole hull. Despite the relatively large surface area it didn't take very long to do and was quite a pleasant task. The object of the filler is to help create a smooth surface. Slippery smooth painted surface? - Slippery, fast little yacht.

The last job was to glass on 100mm wide Dynel tape on the keel and 50mm wide tape to the chines.

My final decision after a lot of procrastination has been to put Dynel tape on the keel and chines rather than fiberglass the whole boat. Apart from the expense, time and additional weight involved I decided that it just doesn't need to be fully glassed. The glass tape is in vulnerable heavy duty wear areas and should be sufficient to protect the hull. The next stage is some sanding and fairing along the tape lines and then a coat of undercoat paint.

6 comments:

George A said...

That's an impressive tape job over the sharp stem! What number of "darts" did you put in the tape in order to get it to hug the curve?

Alden Smith said...

George, interesting that you should mention "darts". I too, thought I would be struggling with this curve (I was ready and waiting like a good seamstress with a pair of scissors), but as it turned out once the resin was applied it all sort of spread out and behaved itself. Maybe the ability to stretch and accommodate compound curves is a property of the Dynal cloth tape. I think (and remembering from experience) that a number of darts would have been required if I was just using Fiberglass tape as opposed to Dynal tape.

George A said...

I must try dynel. Glass tape is a mess to bend around a sharp corner unless one cuts it first on a 45 degree bias, which of course wastes a lot of tape! I wonder--does dynel wet out well or does it like to float on the surface of the resin like polypropylene cloth? Did your dynel tape come with selvaged edges?

Alden Smith said...

Dynel is woven specifically so as to be more flexible when being wrapped around compound curves. When Dynel tape is wetted out it bulks up and becomes raised up above the surrounding un - glassed plywood much more than if fiberglass tape is being used. This is either a blessing or a curse depending on the context. In my case it would have been better to have used FGlass tape rather than Dynel because to fair up these taped areas with West System bog will subtly change the hull shape unless I do a lot of severe sanding of the Dynel. --- I am not sure what "selvaged edges" are?

George A said...

A selvaged edge is one which is bound so that the edge of the cloth will not fray: https://en.wikipedia.org/wiki/Selvage

Alden Smith said...

George. Yes both the 100mm and the 50mm tapes had selvaged edges.... and thank goodness for that. I think it could be an unraveling nightmare without this edge.... as I have found on other occasions when I have had to cut cloth to fit a particular area.