Tuesday, 20 July 2010

Gudgeons and start of rudder

I thought I would make some of the parts for the steering. I don't know what the final arrangement will be but I will be needing a rudder, sleeve, gudgeons and some sort of rudder web to attach the gudgeons to.

Gudgeon mold and released laminate

More layers inside. Messy and sharp!

Trimmed and cut into 2 slices (on bandsaw)
A piece of modern art - no just trying to get HD fill level. God bless hot glue!

Finished gudgeons.

Cutting foam for the rudder. Cut outs for some of the HD inserts.

The foam sheet I am using is very warped, (and perforated,) so I had to make a good resin proof flat bed to glue the foam blank up on. I want to get the core CNC shaped, and to start with a warped blank would not be good at all!

Ready for glueing. As I don't know if the CNC shaping will be done in one piece, or 2 halves I am just glueing up the two halves at present. It is also more difficult to keep 4 layers plus inserts in the right place. Easier to just do it in 2 layers to start with and then glue these two together later..
The finished rudder blank, ready for shaping. It has taken quite a lot of work altogether. I find glueing up large areas can be problematic, as  it is hard to judge the thickness of the glue you are putting on. (I am also admit to being a bit of  a messy gluer!)

I had problems because the HD inserts which I glued up seperately from the main board ended up being a fraction thinner  than the rest of the board. It means when you glue these in place you have to try to hold them centrally in the board. (The centre glue line of the board is the ideal refference point for the shaping) The board has a bit of flex to it as well. I will have to be careful when laminating that nothing is under any stress or flex.

HD and nomal foam

It would I think have been better to do it all in one piece and vacuum bag it. This would have kept everything in the right place and even. Fortunately the board is over thick by about 5mm per side, which should mean that there will be enough material for the shaping.

I have added an extra area of HD foam around the tip and leading edge, just for strength. If you hit anything under the water, this is the area that will make contact first. first.

 I seem to have found a company place which will shape the block for me on a 5-axis CNC machine. We decided to do it in one piece, rather than two. This is mainly because the trailing edge of the finished (slightly undersized) blank is only about 3/4mm wide, -on each half this would reduce to 2mm, at which point the foam is going to disintegrate or get damaged. It also means that you would not have to glue up the two halves and worry about them slipping about.