View previous topic :: View next topic |
Author |
Message |
chophop
Joined: 16 Apr 1996 Posts: 230
|
Posted: Sat Jun 25, 2016 12:18 pm Post subject: Replacing a broken ferrule |
|
|
Is it feasible to replace broken off ferrule? The male end is essentially broken off. |
|
Back to top |
|
|
dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
|
Posted: Sat Jun 25, 2016 2:40 pm Post subject: |
|
|
Depends if you have the time, inclination, shop, tool, and like to work with epoxy resins.
Getting the broken ferrule out of the glued end is no small undertaking, but can be pushed out with a long iron conduit.
Mandrel for the new ferrule can be smaller diameter dowell, wood, and at least 8 layer's of fiberglass, or 3 carbon and 3 fiberglass, with epoxy resins.
Lots of sanding, tight lamination, and more sanding can do the job. |
|
Back to top |
|
|
isobars
Joined: 12 Dec 1999 Posts: 20935
|
Posted: Sat Jun 25, 2016 3:33 pm Post subject: |
|
|
That ... or try a swap meet or the internet for a replacement mast half. I've paid as little as $15 for a new half of a $500 mast. |
|
Back to top |
|
|
thombiz
Joined: 25 Jun 2007 Posts: 799 Location: Corpus Christi
|
Posted: Sat Jun 25, 2016 3:36 pm Post subject: |
|
|
Procedure for replacing a damaged ferrule:
1. Get a donor mast top which has a portion which is pretty close to
the same dia. as the ferrule.
2. Next you need to remove the existing ferrule from the mast
bottom(assumes the ferrule is in the mast bottom, not the top) Do this
with a hammer and a stiff pointy knife, similar to a straight fillet
knife, only stiffer. First, cut the remaining part of the ferrule
flush with the mast end. Next have someone hold the mast for you then,
tapping the handle end of the knife with a hammer like you were
tapping a chisel, slowly take out small slivers of the remaining
ferrule. It will take an hour or more, but when you get down to the
joint between the ferrule and the mast you should be able to have most
of the ferrule removed and only the epoxy holding the ferrule in the
mast should remain.
3. To remove this epoxy, you need to make a tube sanding tool. Get a
5/16" threaded rod about 18" long, plus two nuts to fit the rod, plus
a 4" long piece of pvc pipe about 1" outside dia, plus 2 fender
washers whose dia. is about the same as the diam. as the pvc pipe from
you local hardware store plus some Scotch double sided foam tape.
Using a nut, then washer, then pipe, then washer, then nut, mount the
pipe to the end of the threaded rod.
4. Wrap the 4" PVC pipe with the double stick foam tape. Take a 4"
wide strip of 80 grit sandpaper and wrap it about 3/4 the way around
the plastic pipe, sticking the smooth side of the sandpaper to the
pipe, then add strips of soft foam, between the plastic pipe and the
sand paper as you continue wrapping the sandpaper. The foam strips
will help increase the diameter of the resulting wrapped sandpaper
until it is just slightly larger than the dia. where the ferrule was
removed..
5. Put the free end of this sanding rod into an electric drill, set
the direction of the drill to cause the sandpaper to tighten around
the plastic tube when activated.
6. Gently insert the sanding end into the top of the mast and activate
the drill to sand the inside of the mast. Add or subtract foam as
required to get the sander to fit the mast. Remove the remaining epoxy
and no more. Check progress periodically until remaining epoxy from
the ferrule is removed.
7. Take the small end of the donor mast and stick it into the ferrule
end of the mast bottom until the donor mast just starts to get tight.
Use a marker to mark the donor mast where it meets the mast bottom.
Remove the donor mast and cut it off 12" either side of the mark. This
is the new ferrule blank but it needs to be strengthened and cut to
length. Take the small end of the donor mast and stick it in the large
end of the ferrule until it seats, Mark the donor mast at the two ends
of the ferrule, then remove the donor mast and cut a piece 9" long
from the center of the mast tip between the two lines marked on the
donor mast tip.
8. This 9" piece should seat inside near the center of your ferrule.
Use your tube sander to sand the inside of the ferrule, then hand sand
the outside of the smaller piece so it is rough enough for epoxy to
bond, then using West Systems with a thickener, epoxy the 9" piece
into the middle of the ferrule. You now have a ferrule that is double
thickness and near double strength at the mast joint.
9. Stick the ferrule into the bottom of the mast bottom and let it
slide until it comes out the upper end. Pull on the ferrule until it
just starts to seat, then mark the ferrule at the mast end. This mark
should be roughly at the center of the length of the ferrule.
10. Remove the ferrule from the mast bottom and stick the small end
into the original mast top. Push it until it just starts to seat in
the mast top. You may have to cut a little bit off the small end of
the ferrule to get the top to seat due to a mast plug in the top. When
you get it to seat, mark where the ferrule body meets the end of the
mast top. You don't want the top to fit really tight, just barely, so
add another line 1" above the mark on the ferrule you made with the
mast top. This new line will be the centerline joint where the top of
the mast and the bottom of the mast meet on the ferrule. Now cut the
ferrule no less than 7" either side of this line. roughen the ferrule
for epoxying, spread thickened epoxy slurry for about 8" inside to top
of the mast bottom and on the bottom half of the ferrule, then slide
the ferrule in from the mast bottom pulling it at the upper end until
the centerline just appears, remove excess at the ferrule joint with
paper towel and lacquer thinner. After the epoxy hardens, test the
mast top for fit on the ferrule, and to make sure the between the mast
top and bottom is zero tolerance where they abut. |
|
Back to top |
|
|
chophop
Joined: 16 Apr 1996 Posts: 230
|
Posted: Sat Jun 25, 2016 4:55 pm Post subject: |
|
|
Thank you Thom Biz for your detailed instructions. I do not think that I could perform all of those steps successfully so I won't try but thank you,
Chophop |
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You can attach files in this forum You can download files in this forum
|
|
|