Fixing delamination - SailNet Community
 
LinkBack Thread Tools
post #1 of 7 Old 05-02-2010 Thread Starter
Junior Member
 
Join Date: Oct 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Fixing delamination

I'm new to sailing, and last fall I bought a low price 1978 Mac 2-22. I've been doing minor cosmetic repairs and cleaning. Today's project was to replace the original ceiling carpet.

Once I got the old carpet out, I noticed delamination in two places. One area is significant, about 1 to 2 square feet, and the other is just starting to fail. Both problems are caused by water seeping through the hardware penetrations.

http://cid-ae3d190ae1637b35.skydrive.live.com/self.aspx/Delamination%20area/IMG^_6246%20-%20Copy.jpg

From my inspection, I think there is mold filling the separation void. Both top and underside surfaces are fine.

It appears some previous owner knew about it and re-enforced the plywood in the dinet area. After removing the reenforcements, the area is soft and crunchy.

I would like to repair this properly before putting the ceiling carpet back on. I'm not sure the best way to proceed and am looking for advice. Thanks!
brainiac is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 7 Old 05-02-2010
Senior Member
 
paulk's Avatar
 
Join Date: Jun 2000
Location: CT/ Long Island Sound
Posts: 2,602
Thanks: 4
Thanked 26 Times in 25 Posts
Rep Power: 15
 
To repair delamination properly, you have to know how the structure was put together in the first place. Is there (was there) balsa core, foam, or plywood used between the layers of fiberglass? There are a number of ways to fix delaminations. They depend upon how big the areas are and how much work you want to do. Sometimes you can just inject epoxy in between the delaminated layers and (with a bit of convincing; clamps, pressure, weights, sticks, etc) get them to stick back together. Other times the core material has rotted and needs to be replaced. You have to remove one side of the delaminated area to get at the rotted core. We had a large area of our hull delaminate, and we approached it from the inside, so as not to mess up the awlgripped outer hull. Rotted core material needs to be removed and replaced - generally with the same stuff. If you change the material, it can create hard spots that will cause problems. Wet core material can also be replaced, or if it's in good shape, it can be dried out and re-glassed. Drying out can take a LONG TIME. After fixing the core, new fiberglass needs to be layed up over the patch, hopefully following the same schedule as the original layup. (When you create the opening, at a fine angle, you should be able to uncover the different layers that were used in the original layup.) When you're done you can sand it smooth and paint or gelcoat over it: good (or better!) than new. This is only a rough idea of how to approach this problem. There are books (long ones) that go into more detail and cover various nuances that you may encounter. Most things are fixable. Good luck!
paulk is offline  
Quote Quick Reply Share with Facebook
post #3 of 7 Old 05-02-2010 Thread Starter
Junior Member
 
Join Date: Oct 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
It appears the core is a marine plywood about 3/8" thick, making the total thickness about 1/2". I have full access from the underside, and was on my way to covering it again following the original plywood/carpet design.

If I were to cut out the bad portions of the plywood, how do I ensure the replacement edges have an adequate connection to the existing good plywood?
brainiac is offline  
Quote Quick Reply Share with Facebook
post #4 of 7 Old 05-04-2010
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
scarfing the edges at a 8:1 bevel is the typical way to scarf in a repair, but may be both overkill and almost impossible to do in this case. However, cutting it at a 45˚ bevel and bedding the replacement piece in thickened epoxy would probably be a good start, making sure the edges are well coated with thickened epoxy.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #5 of 7 Old 05-04-2010 Thread Starter
Junior Member
 
Join Date: Oct 2009
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
OK - I put another hour into the project and have some discoveries. First, the inner layer where the majority of the problem lies is just a single layer of fiberglass mat. Fiberglass gets much thicker at the edges.

I decided to cut away the entire thin area that was easy to peel away. Now I have edges toward bow and stern where the ceiling fiberglass and inner plywood are as-one, a laminated assembly.

The next discovery was a seam in the plywood. The bad piece is the one on the outside edge of the boat (since water drains that way). The piece toward the center has not rotted and is just slightly damp on the edge.

Now, I've got the wet wood removed, and have a fairly sloppy shape to fit, with one edge that is straight.

I am wondering how I should fill the core. If I use plywood, which I have enough from the original ceiling carpet backing, I'll have a difficult time getting all the edges to fit well. The surface is curved in multiple ways.

Alternatively, I have a bunch of scrap red oak that I can shape to size, in strips. Red oak is not a good boating wood, but it seems to me if any wood gets wet in this way, it is done; the water is trapped, so penetrations must be sealed well.

I was thinking the oak would perform best because of its stiffness. And if I made two layers of 3/16" thick each, I could run grain perpendicular. This would allow me to tuck some of the pieces into a few voids where wood was removed but inner fiberglass is still in place.

I have an epoxy adhesive to apply as a bedding to bond to the top fiberglass, and clamp. Then I was thinking liquid nails between oak. Then re-glass bottom fiberglass.

Too McGuyver? I'm open to suggestions.

Last edited by brainiac; 05-04-2010 at 10:27 PM.
brainiac is offline  
Quote Quick Reply Share with Facebook
post #6 of 7 Old 05-05-2010
Senior Member
 
tommays's Avatar
 
Join Date: Sep 2008
Posts: 4,295
Thanks: 1
Thanked 30 Times in 30 Posts
Rep Power: 7
 






I found balsa core to best and done in 6" X 24" sections to insure you have good contact with the outer skin

If you try for to much in one shot you will get voids that let it flex

1970 Cal 29 Sea Fever

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1981 J24 Tangent 2930
Tommays
Northport NY


If a dirty bottom slows you down what do you think it does to your boat
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
tommays is offline  
Quote Quick Reply Share with Facebook
post #7 of 7 Old 05-05-2010
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
I'd recommend going with Baltek ContourCore end-grain balsa. This is a far better core material than plywood. Plywood is a lousy core material for several reasons—first, it is heavy compared to end-grain balsa or foam; second, it has the worst characteristics of both balsa and foam—it rots like balsa, and allows water to quickly migrate and delaminate large areas of the hull like foam can.

Use a thickened epoxy to bed the new core material and then layup a proper lower skin of laminate using epoxy resin.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Delamination Erwan Gear & Maintenance 6 11-29-2009 02:12 PM
deck delamination repair Sundowni Gear & Maintenance 0 07-01-2005 09:27 PM
Fixing Chips and Cracks Sue & Larry Her Sailnet Articles 0 07-08-2001 08:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome