Building a F32 Daggerboard
by Rod Tharp
I now have an F32 dagger board. I popped it out of the molds yesterday and
it looks really good.
I have to cook it so it might need a little fairing after that.
I started on the molds about 4 weeks ago when I ordered three sheets of 3/4" 5'x10'
-3 D MDF.
This is uniform density MDF.The board mold is about 104" by 30" and at least
2" thick. Three
sheets of 3/4 gave me 2 1/4" thickness and the 5'x10' sheets ripped in half and cut
to length,
gave me the width and length in continuous pieces. I faced glued three 30" by
104" pieces using
epoxy and vacuum bagging them down. I then put some glass and reinforcement on the back to
prevent warping. To get the mold shaped I took the rough molds to Friday
Harbor where
Brandon at Turning Point Design http://www.turnpoin
tdesign.com/ foils.htm has a CNC machine
and he cut the molds for me. Actually it was a little more complicated than that.
You see
Friday Harbor is in the San Jauns and is a 1 1/2 hour ferry ride from Anacortes which is
three hours
from my house. I wanted to get the cutting done in one day so I left at 2:30 AM to catch
the 6 o'clock
ferry that got to Friday Harbor at 7:30. We then set up the molds and cut them
on the CNC machine,
finishing in time for me to get the last ferry back and getting home at midnight. I then
put three layers
of thin epoxy on the mold, sanded them with 180 grit and waxed and sprayed PVA on them.
Then we
vacuumed bagged the shell laminates and all the unidirectional down to each mold half.
This was then
trimmed to the center line using a router with a guide box. I then made the
center web using three
layers of 15 oz CF sleeving material and glued it to one side and put a reinforcing epoxy
bog around
the perimeter of both molded laminates. The middle area from the bog to the center web was
then
filled with foam and everything routed to the centerline or a little lower actually. Each
mold side had four
locating holes for aligning the halve and using pins in these the halves were bogged and
stuck together.
Plenty of Cee clamps were used to hold the molds together until the epoxy set. I popped
the board out
yesterday and it practically fell out of the molds and I am pleased with it .
The only problem that I have now is making sure the wax is off the board
and that is much harder to do
then I would have thought. I used Partall #2 wax and PVA and nothing seems to really cut
that wax.
(Remove-Does any one have an idea of what can be used.) The advertisement said it was
water soluble- not true.
I used denatured alcohol. water, pressure washer, fiberglass dewaxer from Interlux and
acetone and none
of them really cuts that wax(add-Finally through testing I found that solvent 101
would remove the wax and
is also an epoxy thinner so residue is not an issue) ( remove- I think that I removed most
of it will elbow grease. Kind of frustrating not being
positive that all the wax is removed. It doesn't affect the structure but does affect the
paint adhesion.)
Brandon is making two F35 eliptical type dagger boards for a couple of F33. If any one is
interested
he will have the molds.
I also have molds for the 32 dagger boards if any one is interested in using them.
Rod T on to fairing the bottom and doing bottom paint
Rod Tharp, F-9A -
"Strider"
41- CNC machine
46- Port mold after CNC before epoxy coat
02 Vacuum bagging laminates
06
After vacuum bagging- not trimmed yet
38 Starboard side ready for joining note foam in middle, bog around edges, channel for
center web 47 joining
halves
49 opening up
52- removal from molds- note
squeeze out of joining bog |
