One Down One to Go

Posted by Paul

I have shaped my first daggerboard. It took me all day because as usual I was a little over cautious on this first one. I measured and checked and checked and measured until there was nothing for it but to actually cut one. So I did. And promptly made a mistake. There is a lock on the plunger. The initial depth is set using a dial which raises or lowers the cutter. Then once the required height is set you lock it off and away you go. I forgot to lock it off which is fine if you just push the jig along the rails but I made the mistake of pushing on the router for the last 200mm (I grabbed the handles ready to switch it off) and in doing so I pushed the cutter down into the job another 2mm or 3mm for about 100mm. Not a big problem as it is at the very top of the board rather than the bottom so not under any stresses, but it just nicked the edge of the uni stack and will need filling up with glue again before the blank is glassed. So from then on I remembered to lock the plunger and only pushed on the mdf cross rail. Also my first cut was just a tad too deep, you want the router to just skim or just miss skimming the mould so that the bit does not destroy the mould (I have to use them again on the other blank.)

So with the first tentative cuts I gradually gained in confidence and kept moving the router about 15mm each time (it is a 16mm bit) so that each cut just overlapped the last and adjusted the depth of the cut each time until eventually the shape of the board started to emerge. I had wedges under one side of the router to adjust the angle of the cutter to the angle of the profile. It is quite a relief to get from one end to the other each time and see that the blade was in contact with the board the whole distance and exactly meets the mould at the other end. You know then you have a level straight board being cut.

Once I had the first side shaped, I turned the blank over, set it up in the correct position. This took me half an hour or so of checking with stringlines, the actual placing in the jig took 5 minutes, and then started shaping the other side. At the trailing edge, because I still have to cut a slot for the sail batten I decided not to trim the overhang off yet. I left the full width (40mm) overhanging piece on so that I have more room to find my centreline and cut the slot, then after I have glued the batten in I will trim the last pieces off ready for glassing.

After both sides had been shaped I took the blank out of the jig and ran an orbital sander over it to take off the uneven edges and smooth out the blank. This sanding is not to fair it just to get the surface smooth so that the glass has a nice surface to bond too and no lumps and bumps where air bubbles can form. I have a few holes and cracks where not enough glue joined the foam strips here and there so I will need to back fill these with glue before glassing. Then once it is glassed the bog goes on to fair it and then the only sanding I can do is manual with a torture board.

Although it took a little longer than I anticipated, I still favour this form of shaping over the usual method of planing or sanding the blank into shape using the female mould as a guide. I think it is a more accurate way of getting a uniform shape. I enjoyed today. There are days where you get tangible results and days where you don’t get anything to look at for the work you have done. No prizes for guessing which days are the most satisfying.

Tomorrow I should get the second blank shaped a little faster, although I have to set the moulds on the ends and set it up in the jig. Still I should finish it a lot faster so if time permits I will start on the back fill of the centre spines and gaps and cracks. The trough is now only about 2mm or so (in some places there is barely any trough at all) at its deepest, so I will mix a thick lot of glue and using a large trowel as a screed I should be able to fill the trough to flush neatly or just overfull so I can sand it back to flush ready for the glass layers.

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