Coaming boards - Is epoxy flexible enough to conform to the bend? - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 28 Old 09-23-2011 Thread Starter
Sailors do like Heineken!
 
chrisncate's Avatar
 
Join Date: Jan 2010
Location: Maryland
Posts: 4,574
Thanks: 18
Thanked 34 Times in 34 Posts
Rep Power: 6
 
Coaming boards - Is epoxy flexible enough to conform to the bend?

....

Last edited by chrisncate; 03-03-2015 at 09:50 PM.
chrisncate is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 28 Old 09-23-2011
Tartan 27' owner
 
CalebD's Avatar
 
Join Date: Jan 2008
Location: NYC
Posts: 4,794
Thanks: 5
Thanked 110 Times in 102 Posts
Rep Power: 8
 
One word: NO.
Another non-word: Cetol (Natural Teak of course)

My experience was that for the work I put into epoxying various bits of exterior teak and then trying to varnish over them for UV protection was not at all encouraging. Unless you are willing to stand up to the hard mistress the Varnish is then you will never keep up with the recommended # of coats and the epoxy undercoating WILL start to fail after 2 - 3 years. It will pull up from the surface of your expensive teak or whatever wood is on your boat and you will need to take it all off again in order to finish it properly.
Some urethane varnishes (2 part varnishes that smell like nail polish) promise more long lasting results but I am in no way convinced that the time and effort is worth the expense.
I've tried Interlux Shooner varnish, Bristol Finish (BF) and Cetol and guess which is my running favorite right now? I'll give you a hint: it's not BF or varnish.
The reasons are simple. Cetol is easy to use by even a lobster, it only requires maintenance about once a year and it does not smell like a nail polish factory.
Your mileage will vary.

"The cure for anything is salt water~ sweat, tears, or the sea." ~Isak Denesen

Everybody has one:

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CalebD is offline  
Quote Quick Reply Share with Facebook
post #3 of 28 Old 09-23-2011
Senior Member
 
Join Date: Feb 2008
Location: N. VA
Posts: 656
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 8
 
Send a message via Yahoo to dacap06
Regular epoxy doesn't flex enough for your purpose. The rather expensive G/Flex 650 might, but I'm with Caleb on this one. I think your best bet is Cetol.

T. P. Donnelly
S/V Tranquility Base
1984 Islander 30 Bahama
Pasadena, MD
dacap06 is offline  
Quote Quick Reply Share with Facebook
post #4 of 28 Old 09-23-2011
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 2,896
Thanks: 2
Thanked 76 Times in 70 Posts
Rep Power: 9
 
Sounds like the epoxy may be part of the attachment, not the coating. If so, G/Flex may be the way to go. I've used the thickened stuff that comes in a pair of tubes and it works well. Does cure pretty slowly however.

Last edited by JimsCAL; 09-23-2011 at 10:34 AM.
JimsCAL is offline  
Quote Quick Reply Share with Facebook
post #5 of 28 Old 09-23-2011
Seņor Member
 
PorFin's Avatar
 
Join Date: Sep 2007
Posts: 1,446
Thanks: 8
Thanked 20 Times in 20 Posts
Rep Power: 8
 
Quote:
Originally Posted by chrisncate View Post
The coaming needs to bend in towards the cockpit part that it bolts to, inward (about a five inch deflection on a 10' piece).

I need to install it with cured epoxy where it bolts up, and bed it. Will the epoxy crack you think? I plan on varnish over the rest of the epoxied coaming upon install.

West system epoxy.

Thanks in advance for any insight offered.
CnC,

I'm not quite sure what you have in mind, so I'm not going to discount the suitability of epoxy out of hand.

Could you explain your tentative plan in a little more detail? Are you laminating a new coaming using epoxy?
PorFin is offline  
Quote Quick Reply Share with Facebook
post #6 of 28 Old 09-23-2011
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 16,577
Thanks: 110
Thanked 321 Times in 306 Posts
Rep Power: 10
     
Chris... are you planning on fabricating new 'boards' in place of the original teak? Not real clear from your description. Sounds like everyone else assumes you're treating original teak boards.

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Faster is offline  
Quote Quick Reply Share with Facebook
post #7 of 28 Old 09-23-2011
Senior Member
 
emoney's Avatar
 
Join Date: Jun 2010
Posts: 545
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 6
 
Is the epoxy only going where the two pieces meet, in the "bolt up area"? If so, how much of a bend is there?
emoney is offline  
Quote Quick Reply Share with Facebook
post #8 of 28 Old 09-23-2011
Reward for lost Kraken!
 
hellosailor's Avatar
 
Join Date: Apr 2006
Posts: 11,563
Thanks: 6
Thanked 137 Times in 134 Posts
Rep Power: 11
   
If you want to put a 5" curve in a ten foot board, you don't want to do it that simply.

Traditionally you would steam the board, and you could use a 10-12' long piece of venitlation duct as an improvised steam chamber for this board. Once it is nice and soggy, you take it out, set it in a jig, and let it dry. it will take on the curved shape and hold it.

Or, you don't use a solid board. You use 1/4" or thinner plies, set them in a jig and glue them up and clamp them. When the glue dries (epoxy or a water-proof alternate) again you'll have a curved board.

But to just force a board into that kind of curve? That's brute force, and the board will forever after be fighting whatever you do, trying to get straight again.
hellosailor is offline  
Quote Quick Reply Share with Facebook
post #9 of 28 Old 09-24-2011
Seņor Member
 
PorFin's Avatar
 
Join Date: Sep 2007
Posts: 1,446
Thanks: 8
Thanked 20 Times in 20 Posts
Rep Power: 8
 
Quote:
Originally Posted by chrisncate View Post
I described it poorly, a pic will probably do better explaining than I:

Old pic of old coamings, the new ones are already made, dry fitted up and ready to go on. They are Sapelee mahogany, not teak. See the slight bend? Notice how it also connects to the boat - that's the area I need to figure out how to get a finish on before the install, so it's sealed and protected where it bolts up. Where it connects is about a 3" area along the lower part of the board where it seats into the impression molded into the boat..
CnC,

I'm still a little unsure of what you have in mind, but does this sound right?

You've cut replacement coamings out of Sapele. These are made out of flat stock. You are trying to figure out how to secure them to the boat while accomodating the bend in the cockpit.

I think you're facing a choice of either doing a) what works; and b) what's best.

At this stage in your project, I'm going to side with HS and recommend steam bending the pieces before installation. While you can likely muscle them into place using the through bolts and epoxy, the coamings will always be trying to return to their original flat shape. The combination of these pressures and UV degradation pose a risk of failure. If you steam bend the pieces, you won't need the adhesive proerties of epoxy -- a combo of mechanical fasteners and a decent bedding compound will be sufficient. This will also make it practical to remove them for refinishing in the future; if you epoxy them, that's probably going to entail partial destruction.
PorFin is offline  
Quote Quick Reply Share with Facebook
post #10 of 28 Old 09-24-2011
Tartan 27' owner
 
CalebD's Avatar
 
Join Date: Jan 2008
Location: NYC
Posts: 4,794
Thanks: 5
Thanked 110 Times in 102 Posts
Rep Power: 8
 
So let's see if I finally understand the question here.
There is a 3" deep channel that your coaming boards will fit into? before being bolted through the deck and this is the part of the board you are wondering how to finish?
If the exposed parts of the coaming boards are going to be done in varnish then why not use a few coats of varnish for the 'buried' ends? A coat or two of epoxy would also likely work but ... any finish on this part of the board could simply act to hold moisture in the board. I would think that the important aspect of this joint would be to bed the coamings really well with something like Butyl tape to help keep moisture out of there in the first place. Seems to me that Butyl would be an ideal bedding compound for this application.
As far as the slight bend in the coamings I'll only ask how thick is the Mahogany stock you are using? When replacing sections of our teak toe rail we just screw it and bend it but that is more like 1/2" stock. Maybe a little steam bending as HS suggests if it is 3/4" or thicker stock?
Any pics of the channel the new coaming boards fit into?

"The cure for anything is salt water~ sweat, tears, or the sea." ~Isak Denesen

Everybody has one:

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CalebD is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

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
Jib sheet chafing coaming 4arch Gear & Maintenance 5 11-15-2009 11:44 AM
Coaming boards, Bedding? Tree Gear & Maintenance 2 05-21-2009 06:41 AM
teak coaming boards damaged Morgan3820 Gear & Maintenance 6 10-17-2008 07:02 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