Wednesday, February 04, 2009

Rudder sleeve out of the mold

The plans actually call for the use of sheet wax wrapped around the rudder blade to build up the nesessary room for the frontrunner fabric (a durable marine fabric) that will line the case.  Like the daggerboard,  the rudder on the F22 design is just pulled up and down in the case. No pivoting, which I know some builders would prefer.  I like the simplicity of this design however. The open transom design should give me good access to pulling the rudder up when needed.

Anyway,  I could have purchased the sheet wax from Composites Canada who sell sheets at a .010" thickness.  This is the proper way to do it but it would have required building up quite a few layers of wax, so taking once again the lead from Menno, I decided to try using the fabric itself wrapped in plastic.  This fabric was kindly supplied by Jay in Seattle at a fair price and I have no idea where to source it in my locale. 

Two 2x4's cut with the profile of the rudder blade provide for the mold edge for the upper and lower flanges.  The picture shows the everthing more or less in position.  The fabric was taped in place and compressed to what I hope is the correct amount.  After this I used lots more plastic tape and some dollar store plasticine (horrible stuff made in China),  then finally a number of layers of a mold release wax.  

Here is the first layer of laminate applied.  I let the first layer cure before adding the others.  I'm not sure if this was necessary.

When all the carbon fiber was applied and cured I knocked off the 2x4's from each end.  Then I removed the plastic strip from the trailing edge and was able to break the part from the mold by prying up from that open trailing edge.  It came off no problem.  I did make some initial trimming when the part was still green  and I still have some trimming to do,  but I am off to the next step of adding the pivot tube to the sleeve.

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