Friday, April 30, 2010

Centreboard lay-up

This is a photo of the rudder layup after the peel ply had been removed and the surface was given a light sand ready for the foaming epoxy. Notice the shape of the uni layers, i did this to try and remove excess material were it isn't needed for example the front and rear sections of the foil. As the middle section (thickest) takes the majority of the bending load, and the narrow areas contribute very little to strength and stiffness.

This is the hole drilled into the top of the rudder mould so that excess foam could be allowed to escape from the mould. There is a straw in the hole to prevent the foam sticking inside the hole.

This is the amount of resin we used this time, as you can see from the image it looks like possibly a little to much (this stuff expands to 4 times its volume). We brushed all surfaces as suggested by SP Systems.

This is the excess foam pouring out of the mould, turns out after our failed test pour we got a little carried away. At least there shouldn't be any gaps in this one.

This is the centreboard layup that i used, similar to the rudder in profile and shape, except 1 extra layer for good measure. The layup is as follows:

1x cloth 200gsm cloth at 45 deg
1x full uni 300gsm
6x tapered and progressively smaller layers of uni 300gsm
1x small patch of 200gsm cloth at hull exit.

We applied to the mould i felt that this was way too much carbon, time will tell i guess you never know the extra stiffness might be worth it.

Applying the clear epoxy as a gel coat to the mould beforehand. This was done with a spray gun on the rudder moulds but we could not get it to spray the epoxy well and this gave us a very poor surface. The image above shows us using the gun as cup to hold the resin to brush on after we gave up on the spray gun.

The above images shows the centreboard under vacuum, with the bleed out clearly visible.

Plans for the weekend are the join the centreboard and remove them from the moulds.

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