Dagger Board Rudder Update

I have just started working on the rudder. My main concern was making sure that i got a profile that was true. When you have a high performance boat minor irregularities will tend to create problems at speed.
With that in mind i did a bit of research & found a person in Melbourne that can cut foam with a hot wire CNC cutter.
I gave him the dxf files that Ian gave me & here is the result.
The cutter was not able to shape the tip area but that can be done by hand. Overall i am very pleased with the result.
I think i will get him to do the dagger board as well. My attempts at shaping have left a little bit to be desired.

After much deliberation I decided that the best way to make the rudder was in 2 halves. By using the outer jacket as a mold & slicing the foil sections in half I can make the 2 halves & join them together.
The process that I have used is to mount the outer halves on 2 pieces of 25mm MDF board. I used a spray on contact adhesive for this





Once i had all 7 pieces down the next task was to create a mold for the tip. I did this by covering the foil section in tape & then making a mix of light auto body filler & then pushing the shaped tip section into the bog mix. After it had gone off I removed the tip section & cleaned up the filler.




Next step was to place a sheet of thin mylar film in the mold. I used the spray adhesive for this. I then taped the sides up with clear packing tape lapped over the edge of the mylar film to stop the epoxy from sticking to the foam. Next step was about 5 layers of mold release wax so that it will come out of the mold. I am hoping to make a 2nd spare rudder, just in case.



For the laminations I will only put the 1st layer of DB into the mold. The others will be placed over the complete blade once it is joined & removed from the mold. After the 1st DB layer I will then place the required layers of Uni followed by the other layers of DB for centre core support.
This then is vac bagged. Once done I started to fill in the rest of the internal parts with the shaped foil sections. I had to sand the shaped faces to allow for the laminates already laid down as I did not want to sand too much to get a flat half.
I also laid the balsa core. This was all laid in with a bog glue mix & then I used the vac bag to settle it into place.




This where I am up to at the moment. I am just about to start laying up the 2nd half today & then it will time to join them.