Filling holes in hull with epoxy barrier coat - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 13 Old 08-28-2008 Thread Starter
Junior Member
 
Join Date: Aug 2008
Location: Berkeley, CA
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Filling holes in hull with epoxy barrier coat

I'm in the process of replacing all the old, corroded thru-hulls and valves (most of them gate valves) with new ones. The existing valves were bolted all the way through the hull with stainless steel, which is now corroded almost to dust.

The plan is to remove those bolts, fill in the holes in the hull, and lagbolt the new valves into new (epoxy-sealed) plywood backing plates.

I would normally clean out the holes and fill them with poly filler, then gelcoat over, but the bottom had an epoxy barrier put on a few years ago by the previous owner. Can I still use poly filler, or do I need some kind of epoxy putty? Do I need to seal that, or can I just paint over it?

(Another option that was mentioned was just to glass over the existing corroded bolts on the inside, and to leave them in the hull, but I don't like the idea of sealing a bunch of rusted metal in there.)

Cheers!
slugchewer is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 13 Old 08-28-2008
Handsome devil
 
Stillraining's Avatar
 
Join Date: Jan 2008
Location: LaConner,Washington
Posts: 3,477
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 10
     
Hmmm...are you doing it this way to avoid messing with the new epoxy barrier coat?

Or is it that the existing bolt pattern/holes wont line up with your new seacock flanges?

I personally dont much care for lag bolts in a potentially wet environment..hard to seal the wood...just MHO.
Stillraining is offline  
Quote Quick Reply Share with Facebook
post #3 of 13 Old 08-28-2008 Thread Starter
Junior Member
 
Join Date: Aug 2008
Location: Berkeley, CA
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Mostly because the existing bolts are so corroded that they're no good for anything. I don't really want to see it happening again (with through-hull bolts), so I figured sealing it back up and keeping the bolts inside the boat was best.

One other option was to bolt up through the back of the backing plates... takes care of that lag bolt problem (I know what you mean). I'm not sure yet whether they line up -- will have everything together this weekend.

Either way, I guess I'm still curious about filling those holes... any thoughts?
slugchewer is offline  
Quote Quick Reply Share with Facebook
post #4 of 13 Old 08-28-2008
Handsome devil
 
Stillraining's Avatar
 
Join Date: Jan 2008
Location: LaConner,Washington
Posts: 3,477
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 10
     
I have to admit I have contemplated doing exactly as you described the second time..putting the bolts up through the block only and epoxying the block to the hull forgoing drilling through and having more hull penitrations..BUT..thats not the recommended way of doing it..I think if it were me and the existing hole pattern lined up ,I would reuse the existing holes after cleaning them up and maybe even re drilling them one size larger.

I can relate to the corrosion issue but dont think youll get completely away from it the other way either.

As far as filling the holes most people recommend using thickened epoxy..as it has better secondary adhesion properties...then fair and reapply your barrier coat..No way would I intumb the corroded bolts in the repair no matter which way you go...if they possibly continue corroding they could delaminate your repair from internal pressures..just like a blister does.

Don Casey does a good job of explaning it.
Installing a Seacock by Don Casey

Last edited by Stillraining; 08-28-2008 at 06:58 PM.
Stillraining is offline  
Quote Quick Reply Share with Facebook
post #5 of 13 Old 08-28-2008
Senior Member
 
Maine Sail's Avatar
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,890
Thanks: 20
Thanked 223 Times in 170 Posts
Rep Power: 16
       
They should have never been stainless in the first place and should have been silicon bronze. Replace them with silicon bronze and they will most likely out last you and the boat. Stainless steel suffers badly from crevice corrosion and does not like a moist oxygen starved environment.

______
-Maine Sail / CS-36T


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




© Images In Posts Property of Compass Marine Inc.


Maine Sail is offline  
Quote Quick Reply Share with Facebook
post #6 of 13 Old 08-29-2008 Thread Starter
Junior Member
 
Join Date: Aug 2008
Location: Berkeley, CA
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Stillraining -- that idea was straight from Groco, who recommended that method of installing them.

halekai36 - absolutely my thoughts. Though, Groco recommended SS, not bronze, despite all my persistent arguing. They pointed out the SS ball in the valve.

At the moment, it looks like I'll do the following:
- remove all old hardware, including corroded SS thru-bolts
- fill existing bolt holes with epoxy filler
- cut out round plywood backing plates and seal with penetrating epoxy
- seal backing plates and thru-hulls to hull with 4200
- bed (bronze!) lag bolts into backing plates with Dolphinite

Sounds crazy but it just might work!
slugchewer is offline  
Quote Quick Reply Share with Facebook
post #7 of 13 Old 08-29-2008
Senior Member
 
Maine Sail's Avatar
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,890
Thanks: 20
Thanked 223 Times in 170 Posts
Rep Power: 16
       
Quote:
Originally Posted by slugchewer View Post
Stillraining -- that idea was straight from Groco, who recommended that method of installing them.

halekai36 - absolutely my thoughts. Though, Groco recommended SS, not bronze, despite all my persistent arguing. They pointed out the SS ball in the valve.

I don't know who you spoke to at Groco but the balls in the bronze ball valves are NOT stainless steel they are supposed to be chrome plated red brass. I can assure you it took about three phone calls and many folks before I got a straight answer on this. I still don't know why they are not chrome plated bronze but was told it has something to do with the bronze and the chrome plating..?

If you are going to bolt them internally consider laminating solid fiberglass backing plates, not wood, then drill and tap them for some 1/2 inch long bolts and epoxy or glass the backing plates directly to the hull. Both Morris and Hinckley have solid glass where every thru-hull is installed not wood. Why? It lasts for ever, wood does not, and when your paying a minimum of 750k for one of their boats they damn well better..

The proper fix for any hole in the bottom of your boat is a 12:1 taper even on a small bolt hole. They should never just be filled with a "filler".. A 12:1 taper means that the hole is tapered from the center to twelve times the diameter of the original hole then cloth and mat are used to rebuild the lamination schedule.

I'd still through bolt them!

P.S. Can you let me know who you talked to a Groco? I have spent considerable time on the phone with them for a few articles I've written and many of the folks there have no clue. There are some that do but you may have just got one of the clueless ones as bronze seacocks should always be installed with bronze bolts!

For more info on seacocks feel free to read these two articles.

Seacock Installation

Thru-hull and seacock Primer

______
-Maine Sail / CS-36T


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




© Images In Posts Property of Compass Marine Inc.



Last edited by Maine Sail; 08-29-2008 at 08:07 PM.
Maine Sail is offline  
Quote Quick Reply Share with Facebook
post #8 of 13 Old 08-29-2008
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Actually, IIRC it is twelve times the DEPTH of the area being repaired, not the original hole size, since a 4" hole would require you to grind approximately EIGHT FEET of the hull to repair it.

If the fiberglass has a hole four inches in diameter and is five-eighths of an inch thick, you'd need to taper an area about 20" in diameter from the center of the hole—the original four inch hole and an area about eight inches out from that (since a 12:1 taper for 5/8 = 7.5").

Quote:
Originally Posted by halekai36 View Post
The proper fix for any hole in the bottom of your boat is a 12:1 taper even on a small bolt hole. They should never just be filled with a "filler".. A 12:1 taper means that the hole is tapered from the center to twelve times the diameter of the original hole then cloth and mat are used to rebuild the lamination schedule.
From the West Systems site:

Quote:
Now grind back about 1/8" to 3/16" (depending on how thick the puck is) thickness from the laminate on both sides of the hole on a 12:1 bevel. This will give the beveled area about 5" diameter. Fill the beveled area on both sides with a layered fiberglass patch and epoxy. Once the patches cure, sand them and an area larger than the patch to prep for fairing and finishing. It is especially important to remove all the antifouling paint anywhere epoxy will be applied because epoxy will not stick well to most bottom paints.

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.

Last edited by sailingdog; 08-29-2008 at 08:18 PM.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #9 of 13 Old 08-30-2008
Senior Member
 
Maine Sail's Avatar
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,890
Thanks: 20
Thanked 223 Times in 170 Posts
Rep Power: 16
       
Quote:
Originally Posted by sailingdog View Post
Actually, IIRC it is twelve times the DEPTH of the area being repaired, not the original hole size, since a 4" hole would require you to grind approximately EIGHT FEET of the hull to repair it.

If the fiberglass has a hole four inches in diameter and is five-eighths of an inch thick, you'd need to taper an area about 20" in diameter from the center of the hole—the original four inch hole and an area about eight inches out from that (since a 12:1 taper for 5/8 = 7.5").



From the West Systems site:

Thanks for the proof reading it must have been the wine and beautiful scenery that made me type "hole diameter" instead of "hole depth".

When your sitting on the hook on a remote off shore island with internet cell service and views like the one bellow bad typing can happen..


______
-Maine Sail / CS-36T


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




© Images In Posts Property of Compass Marine Inc.


Maine Sail is offline  
Quote Quick Reply Share with Facebook
post #10 of 13 Old 08-30-2008
Arf!
 
pegasus1457's Avatar
 
Join Date: Apr 2002
Location: Long Island NY
Posts: 609
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
 
Quote:
Originally Posted by slugchewer View Post
I would normally clean out the holes and fill them with poly filler, then gelcoat over, but the bottom had an epoxy barrier put on a few years ago by the previous owner. Can I still use poly filler, or do I need some kind of epoxy putty? Do I need to seal that, or can I just paint over it?
All of the fairing compounds I have tried (3M Filler, Interlux Interfill) strongly recommend overcoating the filled areas below the water line with 4 coats of Interprotect -- before you paint.

Fluctuat nec mergitur
pegasus1457 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
even more exciting...! FILLING HOLES WITH EPOXY geary126 Gear & Maintenance 22 05-03-2007 12:42 AM
Drilling and Filling Holes in Your Boat Sue & Larry Gear and Maintenance Articles 0 03-11-2003 07:00 PM
Gel coat vs epoxy for hull dpoperngr Gear & Maintenance 6 10-28-2002 11:48 PM
Is Vinyl Antifoul better over Epoxy Barrier Coat pds Gear & Maintenance 3 08-27-2001 12:27 PM
Filling Holes with Epoxy Sue & Larry Gear and Maintenance Articles 0 09-25-2000 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