8.11.2010

Spinning the bow pole

it's pretty amazing what can be done with the judicious use of clamps.  Seen here is  an embarrassing arrangement of clamps that allowed me to spin the bow beam so that a final carbon braid sleeve could be applied and wrapped with shrink tape. The horizontal clamp provided a method of adjusting the RPM of the tube.

4 comments:

geoffrey said...

Allen Looking good, did you do multible secondary bondign with fiber stack? Did you start with the shrink wrap in the middle and work out?

Unknown said...

I started out by started out by wrapping the carbon layer by layer following the laminating schedule that Ian offered in the plans. I did this with a friend by rolling the mandrel over the fabric then moving it back to the edge of the table each time we made a wrap. I then vac bagged the entire pole. If I were to do it again, I would have done this in two stages rather than try to apply all of the layers at once. In my instance, I ended up needing to smooth out a few wrinkles with a little sanding so I decided to add a carbon braided sleeve as a finishing layer and that is what I show in this post.

Unknown said...

Allen, I understand that you used UD carbon tape for it. How wide it was (50, 100mm)? Did you overlap them or just put side by side? Did you change reinforcement along the lenght of the bow beam? I mean more carbon in the middle, less at both ends? Regards,
Peter

Unknown said...

After having a local carbon tube manufacturer quote these tubes, it became immediately apparent that the market for specialty carbon spar builders is driven by military contracting, million dollar americas cub boats and formula one projects. I can't blame them because in these cases, a manufacturer gets pretty much establish a profit margin similar to the sale of jewelry.

For me, it made much more since to build them myself. The licensed designs of the Farrier boats call out the laminating schedules for these spars and I am confident that they have been worked out to be a strong as they need to be without being too strong. The uni can be wrapped full length with a full width carbon roll to obtain the proper total weight of reinforcement. Although I don't think it is absolutely necessary apply the wraps of unit so that edges of the start seam aligns to final wrap of the finishing seam, I came pretty close. The biaxial wraps are overlapped so this results in a fairly uniform tube. Common practice for rolling tubes uses a compression surface that rolls along with the tube pressing down on the top of the tube during build and If I ever crash this cat into a dock, the next one i build, I'll build a table that lets me roll the wraps over the mandrel tighter. Since I vac bagged the heck out of the final tube it didn't make that much of a difference.