Daggerboards, Uni directional glass

Uni Wet Into Dagger Spine

Posted by Paul

It takes quite a while to wet out 10 layers of glass into the dagger spines, I did one yesterday, it took me about 2 hours, and did another today for another 2 hours each for 2 more sides today. The 10 layers consist of 7 layers of uni and 3 layers of double bias. The method of wet out is to give a quick coat of resin on the duflex spine then lay a dry uni layer onto it then with a brush wet the tape out. Then once you have coated the entire tape lay the next dry tape onto it and then roll it down with a detail roller (the glassing tool that looks like a series of washers).

A few important tips here, first uni has much thicker strands than double bi glass so it takes a while for resin to soak into the full thickness, so rather than applying more resin wait a minute or so for the resin to soak in then apply resin where it is still dry (easy to spot as the glass stays white where dry), second wherever you get dags or loose threads along the edges cut them off, don’t be tempted to try to wet them down thinking the more strand the better, they are way too much trouble and catch in the detail roller and will then lift the tape and leave air bubbles so its better to just cut them off and finally you have to try to keep the uni threads as straight as possible. It is not too difficult in the trough of the uni spine.

After the 7 layers of uni are down the last 3 double bias wet out much faster as they are thinner and don’t need as much uni, I finish them off with a layer of peel ply. It keeps it all much tidier and also gives the glass stack a pre keyed finish as I will need to fill the trough to the level of the profile.

While the dagger was setting today I set about making the jig I will need to router the blanks to the profile shape. I searched all week for steel or aluminium c section but couldn’t find what I needed at a reasonable price considering that once I make the daggers I have no other use for it, so in the end I decided that I would just make the rails out of mdf. So I got a 16mm sheet of mdf and ripped it into 120mm strips. I will then make 2 L shaped 4 meter lengths as the rails and attach them to the bench. The idea of the mdf is that the edge of each strip will keep the other strip straight and the form of the L section keeps it rigid, then I can run a sliding cross rail along it. I will use a string line to ensure that the rails are attached to the bench straight.

With any luck I may get the jig made tomorrow and have the first dagger side shaped if not tomorrow then during the week.

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