Damaged Top Mast Half - solutions?

Damaged Top Mast Half - solutions?

Post by rand.. » Sat, 07 Feb 2009 11:24:52


Hi,

I have a 75% carbon NP 460 mast, several years old.  The top half is
damaged right near the end - where it attaches to the lower half.
There is a visible line of damage (like a crack, but not quite the
same) about 2-3 inches along the direction of the mast.

Here are the options that have occurred to me. (Getting a new top half
doesn't seem practical)

1.  Get some epoxy and make it a (presumably stronger) one-piece mast.
2.  Try it with the top half of a powerex 100% carbon 460 mast (which
lost its lower half some time ago.)
3.  Cut off the last 3 inches and try to see if it will work.  (I fear
it won't since its already a tight fit.)  If it doesn't fit then maybe
cut off the top 3 inches of the lower half of the mast. (And epoxy -
one piece)
4. Trash it.  Or wait for someone to break the lower half of the same
mast.

Thoughts/suggestions?  Thanks in advance

 
 
 

Damaged Top Mast Half - solutions?

Post by thom.. » Sat, 07 Feb 2009 13:49:36

Cut off the 3" then lightly wet sand the upper portion of the bottom
until the top fits. It shouldn't take too much wet sanding.

 
 
 

Damaged Top Mast Half - solutions?

Post by blub » Mon, 09 Feb 2009 05:47:58


Quote:
> Cut off the 3" then lightly wet sand the upper portion of the bottom
> until the top fits. It shouldn't take too much wet sanding.

agree. Once I did the same for my pacific mast it worked very well.

 
 
 

Damaged Top Mast Half - solutions?

Post by Florian /FFF » Mon, 09 Feb 2009 12:26:25


Quote:
> Hi,

> I have a 75% carbon NP 460 mast, several years old. ?The top half is
> damaged right near the end - where it attaches to the lower half.
> There is a visible line of damage (like a crack, but not quite the
> same) about 2-3 inches along the direction of the mast.

> Here are the options that have occurred to me. (Getting a new top half
> doesn't seem practical)

> 1. ?Get some epoxy and make it a (presumably stronger) one-piece mast.
> 2. ?Try it with the top half of a powerex 100% carbon 460 mast (which
> lost its lower half some time ago.)
> 3. ?Cut off the last 3 inches and try to see if it will work. ?(I fear
> it won't since its already a tight fit.) ?If it doesn't fit then maybe
> cut off the top 3 inches of the lower half of the mast. (And epoxy -
> one piece)
> 4. Trash it. ?Or wait for someone to break the lower half of the same
> mast.

> Thoughts/suggestions? ?Thanks in advance

Number 4.b. seems like a good option, actually.

Most people (me) break mostly the lower halves.

Florian

 
 
 

Damaged Top Mast Half - solutions?

Post by sbdesig » Mon, 09 Feb 2009 21:52:48

If I understand you correctly, the top half of your mast has developed
a hairline crack where it fits over the ferell on the bottom half.
I would recommend getting fiberglass and epoxy and wrapping the
damaged area so that the crack doesn't develop any further
2 or3wraps should suffice!
You dont need to create a one piece mast, just fix the damaged area
and prevent spreading.
If you cut the mast- it may not fir into the ferell correctly, if at
all and give you more problems.

Good luck

 
 
 

Damaged Top Mast Half - solutions?

Post by Andy » Tue, 10 Feb 2009 04:12:36


Quote:
> If I understand you correctly, the top half of your mast has developed
> a hairline crack where it fits over the ferell on the bottom half.
> I would recommend getting fiberglass and epoxy and wrapping the
> damaged area so that the crack doesn't develop any further
> 2 or3wraps should suffice!
> You dont need to create a one piece mast, just fix the damaged area
> and prevent spreading.
> If you cut the mast- it may not fir into the ferell correctly, if at
> all and give you more problems.

> Good luck

That type of damage usually only occurs when the two pieces of mast
aren't completely joined before applying downhaul tension.  I've made
a habit of running my finger over the joint before adding significant
downhaul tension, just to double check...  Others wrap the mast with
electrical tape before sliding it into the sail...  Just a few tips to
keep the same thing from happening again!

If you do end up looking for more tops, check the fit with Fiberspar
pieces as well, as they'll probably work just as well as the original
pryde.

 
 
 

Damaged Top Mast Half - solutions?

Post by Wolfgang Soerge » Tue, 10 Feb 2009 07:56:13

Quote:

> Hi,

> I have a 75% carbon NP 460 mast, several years old.  The top half is
> damaged right near the end - where it attaches to the lower half.
> There is a visible line of damage (like a crack, but not quite the
> same) about 2-3 inches along the direction of the mast.

> Here are the options that have occurred to me. (Getting a new top half
> doesn't seem practical)

> 1.  Get some epoxy and make it a (presumably stronger) one-piece mast.
> 2.  Try it with the top half of a powerex 100% carbon 460 mast (which
> lost its lower half some time ago.)
> 3.  Cut off the last 3 inches and try to see if it will work.  (I fear
> it won't since its already a tight fit.)  If it doesn't fit then maybe
> cut off the top 3 inches of the lower half of the mast. (And epoxy -
> one piece)
> 4. Trash it.  Or wait for someone to break the lower half of the same
> mast.

> Thoughts/suggestions?  Thanks in advance

I once repaired a mast which actually split the same way just above the
ferule, using high-quality epoxy (leftovers from boardbuilding) and
unidirectional carbon fibers. Seemed stronger than before and did not
break again to the best of my knowledge - but also did not use the mast
again in any kind of "difficult" conditions (like offshore winds or
currents). Also repaired a mast wich completely broke just above the
boom, using a piece of a lonesome top as ferule. and again leftover
UD-Carbon from boardbuilding. So yes, repairing mast is feasible. Is the
response curve still the same? Probably not. Ist the strength the same
as before? As far as the repaired area is concerned, IF it is done
right: probably yes but it is hard to rule out that the mast has other
damaged areas or that the boundary between repair and original material
is not posing dangers due to unsteady strength/response. So i would not
really recommend DIY jobs on masts if you are not familar with carbon
laminating jobs. So: If in doubt: Option 4. A repaired mast might still
be of good use, together with equally questionable sail and booms, for a
land sailor!

Servus from frozen Bavaria

Wolfgang

 
 
 

Damaged Top Mast Half - solutions?

Post by Brian Sangeorza » Wed, 11 Feb 2009 02:08:10

If you want to try to fix it yourself, I'd suggest using a carbon-fiber
sock.  This is a braided sock, like the old "chinese finger cuffs".  I
bought some at aerospace composites
http://www.acp-composites.com/ACP-CAT.HTM
a few years back and repaired what may be the same problem you're having.  I
had a hairline crack at the open end of the top section.  I sanded the area
around the crack (around the whole circumference).  Then, I put two layers
of sock, pulling each piece tight  and securing it with tape, and then
wetting down the two layers together.  I didn't vacuum bag it, but pulling
the sock tight seemed to minimize bagging and extra resin.  I didn't wet all
the way up to the tape, making it easy to cut off the dry fabric when
finished.  Gave it a sanding and then light coat of resin to cover the
fibers.  That mast has held up for years since the repair (YMMV).  It's
packed away for the winter, but I can get the mast down and send pictures of
the final repair - didn't document the process.
Brian


Quote:
> Hi,

> I have a 75% carbon NP 460 mast, several years old.  The top half is
> damaged right near the end - where it attaches to the lower half.
> There is a visible line of damage (like a crack, but not quite the
> same) about 2-3 inches along the direction of the mast.

> Here are the options that have occurred to me. (Getting a new top half
> doesn't seem practical)

> 1.  Get some epoxy and make it a (presumably stronger) one-piece mast.
> 2.  Try it with the top half of a powerex 100% carbon 460 mast (which
> lost its lower half some time ago.)
> 3.  Cut off the last 3 inches and try to see if it will work.  (I fear
> it won't since its already a tight fit.)  If it doesn't fit then maybe
> cut off the top 3 inches of the lower half of the mast. (And epoxy -
> one piece)
> 4. Trash it.  Or wait for someone to break the lower half of the same
> mast.

> Thoughts/suggestions?  Thanks in advance