Paul Thompson wrote:
Rudolf van der Brug wrote:
I built two rigs to Rob Denney's plans. That included mast (17.5m), boom and everything
related to get things working.
Those were carbon masts built following a system Rob thought up.
Although it worked I would use a different method now, building two halves and joining them together. They would be vacuumed in a mould and post cured ,so very good specifications are possible. If it's up to me I would have them engineered to have them stiff enough. Strenght should be way past what you need in a stiff carbon mast.
Hi Rudolf,
Could you fill us in on how you go about building your own carbon masts? Tell us more about Rob Denney's or where one could go to find out. What are the issues with building your own? More information would be most welcome.
Hi Paul,
First of all, I am a professional builder and the rigs I mentioned were built for owners.
The building method of those masts was quite complicated and risky.
The idea was to end up with a seamless pole. That means you start with a flat piece of cured glass that is laid up with carbon(0 deg.) and more glass(+-45deg.) and then while still wet rolled into a tube using lots of stuff to keep it all under control.
The soft tube is inflated with a pressure bag inserted at the start of the rolling sequence. The ends are closed with wooden discs, one of which has the air hose through it providing the pressure. Putting the pressure on is the frightening bit.
If things go well this leaves you with the primary tube. This is covered with more glass and carbon which are rolled around the tube and concequently vacuumed. The masts were post cured at 60degC.
The masts I built this way are stiff and strong. They are both on Visionarry proas designed by Rob Denney. One is Blind Date, which boat I built entirely, and the other is on ONO, which has a Finnish owner.
In the meantime I've thinking about different ways to build carbon masts. I would probably
use a half mold now and vacuum the halves, joining them together later.
Building your own carbon mast can be done. But if they are to be of any serious lenght risks are getting bigger. You don't want (too many) air bubbles inside the laminate.
So you have to use vacuum or pressure, or both to get the air out.
You need to do tests to try the method, and have samples to check the laminate.
If taken seriously it is quite a task. As a job it is a challenge and it keeps you busy thinking of new solutions.
if you have more questions, please ask
regards,
Rudolf