 |
|
21-06-2012, 03:57
|
#1
|
Registered User
Join Date: Jun 2010
Location: Brisbane
Boat: 320 Catalina and a 16ft Scruffie " Oma Martha"
Posts: 290
|
Balsa Core Deck Repairs
My boat ( 40ft Challanger) has a deck stepped mast and the deck is balsa core.
The rigging is getting replaced and the mast is removed. I found some rot under the mast foot. After further investigation I found that the junction box in front of the mast has let water in the core.
The damaged part is about 12 inch by 8 inch. My thought was to dig out the rotten balsa and replace it with a solid piece of hardwood glassed in with polyester resin. I left the inner glass layers in tact .I am getting rid of the junction box and make sure the whole repair is waterproof. Would it be better to build up with glass to make it more solid for the mast foot or is the hardwood block a good way to go?
Should it have had the balsa core under the mast foot in the first place?
I would think that something more solid would have be a better way to go when the boat was build.
Cheers
Reiner
|
|
|
21-06-2012, 04:14
|
#2
|
Registered User
Join Date: Apr 2010
Location: Newport News VA
Boat: Egg Harbor sedan cruiser 1970
Posts: 958
|
Re: Balsa Core Deck Repairs
Balsa is a soft wood. Why not get some Pressure treated deck boards or dimensional lumber? Pick out tight grained pieces.
That would have to be better than something that will rot.
IPE is a very strong heavy hard wood or a white oak, neither will rot for a long time. Red oak or Ash, both common hardwoods will rot in a few year if it gets wet.
I also use a lot of PL premium polyurethane construction adhesive which is waterproof.
|
|
|
21-06-2012, 06:19
|
#3
|
Registered User
Join Date: Jul 2009
Location: Saint Augustine, FL
Boat: 1975 Downeaster 38' Cutter
Posts: 363
|
Re: Balsa Core Deck Repairs
If you have the patience for it, I would build up solid glass right there.
|
|
|
21-06-2012, 14:14
|
#4
|
Marine Service Provider
Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,882
|
Re: Balsa Core Deck Repairs
I agree - solid glass is best. You could buy some G10 of the correct thickness instead of laminating to that thickness. I would use epoxy.
|
|
|
21-06-2012, 14:19
|
#5
|
Resin Head

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,205
|
Re: Balsa Core Deck Repairs
+1 for G10. The only way to go for this.
|
|
|
21-06-2012, 14:52
|
#6
|
Registered User
Join Date: Dec 2008
Location: ontario canada
Boat: grampian 26
Posts: 1,743
|
Re: Balsa Core Deck Repairs
I just redid mine and removed the rotten balsa and replaced it by casting it in west epoxy mixed with west 404. The area in question was about 4x6x3/8. the actual step is a raised section of marine ply which I replaced with same after sealing all surfaces with straight epoxy resin and built it up using layers of glass mat. The boat is a 1975 so the repair should outlast me. I have a few dodgy stanchion bases that will get the epoxy 404 treatment.
|
|
|
21-06-2012, 15:37
|
#7
|
Registered User
Join Date: Jun 2010
Location: Brisbane
Boat: 320 Catalina and a 16ft Scruffie " Oma Martha"
Posts: 290
|
Re: Balsa Core Deck Repairs
I didn't know G10 fibreglass boards, I have to find out where to get them here in OZ. Looks like a smart way to go.
Thanks for your replies. What would we do without the Cruisers Forum.
Cheers
Reiner
|
|
|
21-06-2012, 18:57
|
#8
|
Marine Service Provider
Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,882
|
Re: Balsa Core Deck Repairs
If you can't find G10 locally it can be made easily.
|
|
|
21-06-2012, 20:45
|
#9
|
Registered User
Join Date: May 2009
Location: Massachusetts
Boat: 40' Silverton Aftcabin with twin Crusaders
Posts: 1,792
|
Re: Balsa Core Deck Repairs
For those who have never worked with G10, you will have a quick learning experience. The stuff even growls at you. Good stuff but a bitch to work.
Foggy
|
|
|
21-06-2012, 20:58
|
#10
|
Resin Head

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,205
|
Re: Balsa Core Deck Repairs
Quote:
Originally Posted by mitiempo
If you can't find G10 locally it can be made easily.
|
I build a lot of fiberglass flat stock, but no you can't make G10 at home. G10 is compressed in hyrdaulic press mold while it's still a wet laminate, at about 60k lbs. force if I remember correctly. This means the resin/fiber ratio is down around 30%, even lower than the best vacuum bag can make. You cannot reproduce this in a non-industrial setting. For high strength plate G10 is the way to go. In this case I agree that any flat stock would be more than strong enough, but there is a big difference between the two.
|
|
|
21-06-2012, 21:01
|
#11
|
Marine Service Provider
Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,882
|
Re: Balsa Core Deck Repairs
I didn't mean you could make G10 but you can lay up a panel that is plenty strong enough.
|
|
|
21-06-2012, 22:36
|
#12
|
Moderator Emeritus
Join Date: Aug 2005
Location: Carlsbad, CA
Boat: 1976 Sabre 28-2
Posts: 7,505
|
Re: Balsa Core Deck Repairs
Any non compressible core will do. You could even use 'starboard' as the core for that small a patch. Are you sure it's balsa core, btw. I doubt that any boat builder would use Balsa Core where it would be subject to compression by the mast. SOP was to use plywood core in the mast area.
__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
|
|
|
21-06-2012, 22:48
|
#13
|
Marine Service Provider
Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,882
|
Re: Balsa Core Deck Repairs
Not much sticks to Starboard - no sealant that I know of nor epoxy. If the skins aren't bonded to the Starboard it couldn't be structural.
Plywood - although not the best choice - would be better than Starboard.
|
|
|
22-06-2012, 00:16
|
#14
|
Registered User
Join Date: Nov 2006
Location: Back in Northern California working on the Ranch
Boat: Pearson 365 Sloop and 9' Fatty Knees.
Posts: 10,488
|
Re: Balsa Core Deck Repairs
I would use G 10 with Epoxy/Cabosil/Mill fiber slurry. A little slurry at a time so no heat is produced.
McMaster-Carr has G 10. Hope this helps
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"
|
|
|
22-06-2012, 00:52
|
#15
|
Registered User
Join Date: Dec 2009
Posts: 2,959
|
Balsa core is is very incompressible. The problem was the leak not the material. I tend to respect the original designers choice and would replace with the same by removing an inner or outer skin and rebuilding appropriately.
|
|
|
 |
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|