Friday, November 29, 2013

Trimming weight

I spent much of the day today trimming down the centerboard and rudder weights.  The top surface is not smooth as poured and if there is extra lead the halves don't fit together well.

The lead is soft and can be worked with woodworking tools like scraper, bench plane, etc., but that's a lot more work than I thought it would be.

I resorted to my old Atlas shaper to do the job.

I had to reposition the weights to get the parts that were under the clamps.  And the centerboard weights exceeded the capacity of the machine, so had to move them around a couple times.

Here's a shot of the underside of a centerboard weight as poured.  I ended up filling in some of the larger voids with fresh lead.

This whole process took a lot longer than I had hoped, and it will be good to have it all glued together.

Thursday, November 28, 2013

Lead Pour - centerboard and rudder

Thanksgiving Day in the shop - I worked today on adding lead ballast to the centerboard (22 lbs) and the rudder (2 1/2 lbs).  The latest plans addendum was published just in time.

Starting with the centerboard, I used a large calipers to verify the thickness, marking the 13mm contour so the router would not break through at a depth of 10mm.  

I calculated how much space was needed and built a template for the router out of one of the offcuts from the kit.  I fastened the the template on with 1/2" pins driven with my Cadex 23 gauge pin nailer, which worked great.  When done, the template pulled off, leaving the pins, which I pulled with a pliers.  I cut to a depth of 10mm and left an island in the middle so the router wouldn't dive in, and later put a big base on the router and removed the island.

I did the same for the rudder, but cut these only 7.5 mm deep.

I got out my little aluminum foundry and fired it up to melt the lead.

Fun to pour metal...

There must be a bit of moisture in the plywood, as the lead bubbled and boiled.  This was a much bigger issue on the centerboard pours which have a lot more metal in them.  

Due to the bubbling, there are some voids in the underside that I may fill in after I get things smoothed out and check the final weight.

So, I'm happy with this progress today!