Sunday, April 6, 2008

Making beams

Hi again, I'm back. And with a lot of new things happening.

I was going to do the main hull now, but went for the beams instead as I want to paint the floats now. So I can paint floats in the new workshop, and do beams in the old. I like to do more than one thing at the time, to be able to do different kinds of work, or spread out more nasty jobs , like sanding.

First a jig is build.

In center is the recess for upper folding strut (UFS).

The surplus of the chipboard is used to for another jig used for making upper corner and the top of the beam.
The corners are heat formed as described earlier on this blog (see floats).

A flange is formed. More on this later.

I have to do this for 4 beams as with all processes when building your own beams.

Also these parts will be needed. Fiber bearings for UFS. ( why is the circles carbon? Because I had a nice pro-made piece at hand, thats why!)

Making daggerboard case

Daggerboard case is normally done in plywood and wooden battens, but i saw that the F22 is done over a mold with glass tapes as joints. So I opted for this solution. Also I made the foil longer and slimmer than the original, that is referred to as high aspect foils.
Doing so I made the case width 120 mm shorter( than original).

Here I made a full scale model of my idea. Board up.

And down. The original board is also seen

F 35 board. It is sticking up higher than normal. Mast raising is done ether on the water or using a special u shaped gin pole.

Laying up the ply and reinforcement. Black band is a double 300 g/m Uni carbon, both sides.

Vacuum bagging port side with the groove for down line and block.

After cure. Mold visible under part. This is just some chipboards with plastic tape. Used a crowbar to release!!!!

Film and bleeder to the garbage. ( delivered to waste deposit as paint to be destructed)

More carbon after joining the two parts. Also see Rogers F22 Page for more info.

Starboard side.
Port side. Hole for down block screws set from inside glassed over. Inside is painted with epoxy added graphite powder. I will paint anti-foil later.

Curing floats at 50 celsius

First I need to cure floats. The epoxy will get stronger if temperature is raised. My Ampreg 22 cures fully if temp. is raised to 50 C. in 14 hours, or 70 C. in 5 hours. So if the high level can be reach it is cheaper to do this!

But to get to even 50 C was difficult for me. I made a tent from alu. tubes and plastic and tried to insulate as well as possible. Next time I will prepare this better as insulation is key. I used a 9 kW electric fan heater placed at one end, and an 200 mm air duct from the other end, to return air back into the heater. This way the heat was evenly distributed.

After 14 hours at 50 C they were finally done.

Lesson learned:
Do this before fairing.
Insulate well.
Get an airdust or similar.