Wednesday, December 03, 2008

Rudder blade foam shaping

Fellow builder Menno had a idea that he shared on the builders group.  He wrote

"My idea is to draw lines on the blank lengthwise, combining all points where the rudder/centerboard has the same thickness. Then use a router to make grooves with the correct depth and use those grooves as a guide..."

Something about this idea stuck with me and the thought of again artistically shaping the blade through the use of the templates seemed like a lot of work.  I know,  I shaped the daggerboard that way last winter.  So I decided to give the router approach a try.

Above is the block of foam with the high density inserts in place.  The block is thicker than required but I wanted to glue the foam  so that the centre had a glue joint.  I also applied a light fiberglass cloth in this centre joint (as I did on the daggerboard)  so that this thin blade might hold together a bit better.  Using the full size plan I transferred the lines.  All the arrows are to remind me to keep the cutter to the outside. 

I've used this mini-router before to create rebates where needed.  This time it is being put to very good use.
Removing the extra block thickness.

I used the oribital sander to get the shape close and then finally some hand sanding. 

And viola, here it is,  close enough to start work on getting the high density foam core inserted down the middle.   I wish I had made the daggerboard this way, this approach is much easier for me.  


Anonymous said...

Wow, great technique! Looks perfect. Andrew.

Menno said...

I'm glad you took the change to test my idea and that it worked. I haven't found time to work on the rudder + centerboard, but when I do I'll see if the router-approach works as good on western red cedar.