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Re: Dagger Repair [Re: yurdle] #266273
10/15/13 08:39 AM
10/15/13 08:39 AM
Joined: Jan 2009
Posts: 5,525
pgp Offline
Carpal Tunnel
pgp  Offline
Carpal Tunnel

Joined: Jan 2009
Posts: 5,525
"Avoiding the bottom." There's an idea.


Pete Pollard
Blade 702

'When you have a lot of things to do, it's best to get your nap out of the way first.

-- Have You Seen This? --
Re: Dagger Repair [Re: pgp] #266283
10/15/13 12:50 PM
10/15/13 12:50 PM
Joined: Dec 2001
Posts: 5,590
Naples, FL
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,590
Naples, FL
Didn't the Stiletto cats use Nomex cores?

I thought I saw a honeycomb core on one which had a porthole removed for replacement...


Jay

Re: Dagger Repair [Re: waterbug_wpb] #266315
10/15/13 06:29 PM
10/15/13 06:29 PM
Joined: Apr 2012
Posts: 190
B
Bille Offline
member
Bille  Offline
member
B

Joined: Apr 2012
Posts: 190
Originally Posted by waterbug_wpb
Didn't the Stiletto cats use Nomex cores?

...


OUCH -- this will boarder-line on Mean :

http://stiletto.wildjibe.com/portfolio/Port_4/photo_15.jpg

And that is why northsea junkie said this :

Originally Posted by northsea junkie

...

I'm still very surprised that they use it in boatbuilding. If you have followed the last Volvo ocean races, you certainly have seen the complete delaminated panels on the Imoca boats (all with honeycomb sandwhich core).
...



Bille


Re: Dagger Repair [Re: yurdle] #266316
10/15/13 07:10 PM
10/15/13 07:10 PM
Joined: Feb 2005
Posts: 4,118
Northfield Mn
Karl_Brogger Offline
Carpal Tunnel
Karl_Brogger  Offline
Carpal Tunnel

Joined: Feb 2005
Posts: 4,118
Northfield Mn
Marstrom boats use a nomex core. At least their Tornado did.


I'm boatless.
Re: Dagger Repair [Re: yurdle] #266342
10/17/13 05:27 PM
10/17/13 05:27 PM
Joined: Oct 2002
Posts: 307
maui
jollyrodgers Offline
enthusiast
jollyrodgers  Offline
enthusiast

Joined: Oct 2002
Posts: 307
maui
@bille Adding resin to your example is what i am describing.
A tshirt saturated with rein won't soak up water after curing, but if you were to sand the edge exposing the fibers, would the fibers be able to soak up water?
My contention is that after carbon or glass is saturated with resin, even if you sand the edge, exposing fibers, that the fibers won't soak up much water. You can dry it off, lightly skuff it and bond to it/paint it etc.
If you try that experiment with kevlar water will soak in and if it's salt water you will never get the salt out.
You will need to glass the salt in and the fuzz down; being careful not to sand back thru.

There is a whole big thread out there in cyberworld about honeycomb & Acats. Some of them use it.
Billl Higgins' Stilletos most definitely were made using aircraft honeycomb and prepreg.
Problems with honeycomb delam seem to be worked out. Once honey comb got to Tornados, they never looked back.
They still have wood rudders and maybe the boards too. I think he does prepreg over the wood.
Also there were honeycomb surf boards in the 60's that are still around today.
So all the cool kids have honeycomb/prepreg these days. i assume: the AC 45's and 72's, some Ccats, those big 60 and 70' tris, but that isn't my field so not 100 percent sure about some of those boats.

As for trailing edge thickness-it's personal taste. You want them as thick as possible without slowing you down too much.. I think if you leave it perfectly squared off. you will get humm. rounded corners-no humm, but is it slower?

for future readers: For this particular repair it sounds like; try a small fill job first, and if it keeps chipping off, make it into a bigger job. one way would be to grind both sides down enough- (roughly the thickness of 3 layers of material), say 2-3" in from the trailing edge, so that after you glass it, the result will fair down nicely. The stronger the materials that you use, the better the repair will last. And off course customize the the trunk so that it isn't as likely to damage your precious foil.

Re: Dagger Repair [Re: jollyrodgers] #266346
10/18/13 03:37 AM
10/18/13 03:37 AM
Joined: Aug 2011
Posts: 774
Greenville SC
bacho Offline
old hand
bacho  Offline
old hand

Joined: Aug 2011
Posts: 774
Greenville SC
Originally Posted by jollyrodgers
@bille Adding resin to your example is what i am describing.
A tshirt saturated with rein won't soak up water after curing, but if you were to sand the edge exposing the fibers, would the fibers be able to soak up water?
My contention is that after carbon or glass is saturated with resin, even if you sand the edge, exposing fibers, that the fibers won't soak up much water. You can dry it off, lightly skuff it and bond to it/paint it etc.
If you try that experiment with kevlar water will soak in and if it's salt water you will never get the salt out.
You will need to glass the salt in and the fuzz down; being careful not to sand back thru.

There is a whole big thread out there in cyberworld about honeycomb & Acats. Some of them use it.
Billl Higgins' Stilletos most definitely were made using aircraft honeycomb and prepreg.
Problems with honeycomb delam seem to be worked out. Once honey comb got to Tornados, they never looked back.
They still have wood rudders and maybe the boards too. I think he does prepreg over the wood.
Also there were honeycomb surf boards in the 60's that are still around today.
So all the cool kids have honeycomb/prepreg these days. i assume: the AC 45's and 72's, some Ccats, those big 60 and 70' tris, but that isn't my field so not 100 percent sure about some of those boats.

As for trailing edge thickness-it's personal taste. You want them as thick as possible without slowing you down too much.. I think if you leave it perfectly squared off. you will get humm. rounded corners-no humm, but is it slower?

for future readers: For this particular repair it sounds like; try a small fill job first, and if it keeps chipping off, make it into a bigger job. one way would be to grind both sides down enough- (roughly the thickness of 3 layers of material), say 2-3" in from the trailing edge, so that after you glass it, the result will fair down nicely. The stronger the materials that you use, the better the repair will last. And off course customize the the trunk so that it isn't as likely to damage your precious foil.


For hum, sanding the trailing edge at an angle can get rid of it.

Re: Dagger Repair [Re: jollyrodgers] #266354
10/18/13 07:05 AM
10/18/13 07:05 AM
Joined: Jun 2009
Posts: 524
Petten Netherlands
N
northsea junkie Offline
addict
northsea junkie  Offline
addict
N

Joined: Jun 2009
Posts: 524
Petten Netherlands
Originally Posted by jollyrodgers
@bille
Problems with honeycomb delam seem to be worked out.


What how??????????

Did you ever have a sheet of honeycomb in your hands and start wondering how in heavens name the exterieur laminate layers should bond to the extremely thin headsides of the honey comb. (without loosing too much weight in extra connections)



ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: Dagger Repair [Re: yurdle] #266358
10/18/13 10:31 AM
10/18/13 10:31 AM
Joined: Apr 2012
Posts: 190
B
Bille Offline
member
Bille  Offline
member
B

Joined: Apr 2012
Posts: 190
There's a test the Gov labs do to a honeycomb laminate
called the Peal-ply test ; they glue one side down, and
measure how much force it takes to remove the exposed side
from the honeycomb panel. Optimum skin weight for peal resistance
is 10oz skin or better. Adding more thickened epoxy
to disperse the energy to the cell walls, will add more weight.

I totally trust my Exxtacy to Not De-laminate while
i'm flying. But if it's Water i'm asking the honeycomb
to deal with than i'd keep the lamination width limited
to 1 inch strips to isolate the tears in a De-lam panel.

Remember they use honeycomb in the fins of Very high
speed rockets and also in some fighter-jet structures, and
it holds up Well ; i would Never trust my life to the stuff
on a boat , unless special precautions were utilized !!!

Bille






Last edited by Bille; 10/19/13 03:52 PM.
Re: Dagger Repair [Re: yurdle] #273284
06/19/14 05:19 AM
06/19/14 05:19 AM
Joined: Nov 2011
Posts: 382
SE MI / NE IN
rehmbo Offline
enthusiast
rehmbo  Offline
enthusiast

Joined: Nov 2011
Posts: 382
SE MI / NE IN
Digging up an old thread -

Goodall Design just published a series of videos on proper dagger/rudder trailing edge repair. Link here

Looks like I have a fun little project before the next regatta. Anyone have a preferred source for carbon cloth?


Jeff R

H18, C2 USA1193
cramsailing.com
crescentsail.com
Re: Dagger Repair [Re: rehmbo] #273291
06/19/14 09:55 AM
06/19/14 09:55 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
uscomposites.com


Jake Kohl
Re: Dagger Repair [Re: rehmbo] #273295
06/19/14 02:28 PM
06/19/14 02:28 PM
Joined: Jun 2001
Posts: 3,906
Clermont, FL, USA
David Ingram Offline
Carpal Tunnel
David Ingram  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 3,906
Clermont, FL, USA
Originally Posted by rehmbo
Digging up an old thread -

Goodall Design just published a series of videos on proper dagger/rudder trailing edge repair. Link here

Looks like I have a fun little project before the next regatta. Anyone have a preferred source for carbon cloth?


That was the best use of 7 minutes in quite some time.


David Ingram
F18 USA 242
http://www.solarwind.solar

"Do or do not. There is no try." - Yoda
"Excuses are the tools of the weak and incompetent" - Two sista's I overheard in the hall
"You don't have to be a brain surgeon to be a complete idiot, but it helps"
Re: Dagger Repair [Re: rehmbo] #273422
06/24/14 05:37 AM
06/24/14 05:37 AM
Joined: Aug 2011
Posts: 774
Greenville SC
bacho Offline
old hand
bacho  Offline
old hand

Joined: Aug 2011
Posts: 774
Greenville SC
Originally Posted by rehmbo
Digging up an old thread -

Goodall Design just published a series of videos on proper dagger/rudder trailing edge repair. Link here

Looks like I have a fun little project before the next regatta. Anyone have a preferred source for carbon cloth?


Thanks for sharing those links. Certainly made it look easy!

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