Reply
 
Thread Tools Display Modes
 
Old 04-26-2012, 03:13 PM   #1
Guru
 
City: Full Time Cruising East Coast
Country: USA
Vessel Name: Meridian
Vessel Model: Krogen-42
Join Date: Aug 2011
Posts: 756
Removing a thru-hull

I have a 1.5" thru-hull that I want to remove. The core is solid about 1 thick. Does the following sound feasible?
1. Remove the fitting. 2. Cut a circular groove in the sidewall of the hole. 3. Fill the hole with thickened epoxy. The idea is that the epoxy that fills the grooved area will lock the plug in place.
__________________
Advertisement

meridian is offline   Reply With Quote
Old 04-26-2012, 03:40 PM   #2
Guru
 
Tony B's Avatar
 
City: Joe Wheeler State Park, Al
Country: Cruising/Live-Aboard USA
Vessel Name: Serenity
Vessel Model: Mainship 36 Dual Cabin -1986
Join Date: Jul 2011
Posts: 1,250
That is way too risky.

The usual way of filling a hole would be working from the outside.
Grind the outside of the hole at about a 12 to 1 slope till you get close to the inside.
Then cut a pile of fiberglass circles all different diameters starting with about 1" larger diameter the final hole size on the inside and working your way up to the newly faired out sloped outside with some extra diameter to spare. Each piece can be slightly larger than the the one below it by about 1/2" Make at least 2 pieces for each size. This may sound like overkill, but it is considered the proper way.
Sometimes, repairs can be done similarly with the only difference being that you grind the outside down to about a 3/4" depth and then do the same grinding routine on the inside of the boat if you have decent access. This will give a patch from both sides.
Be prepared for lots of grinding and sanding.
The layers should be made by using the glass and epoxy. It is highly recommended instead of the logical choice of glass and polyester resin, even though the original hull was probably made with glass and polyester.
I would use fiberglass mat for most of the trip and glass cloth for the last 2 layes or so. This will make fairing out a lot smoother.
__________________

__________________
Cruising the Eastern U.S. Inland Waterways and Gulf Coast. Presently on the ICW in Louisiana and heading Back to Texas.
Tony B is offline   Reply With Quote
Old 04-26-2012, 04:19 PM   #3
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
Tont B is describing the right way to fill a hole in fiberglass. It's in the books if you want more detail. Something about a "secondary bond".

The easy way is to leave the thruhull in place and cap it off on the inside. There are a couple different ways to do this, depending on whether the truhull is threaded or barbed.
rwidman is offline   Reply With Quote
Old 04-26-2012, 06:33 PM   #4
Guru
 
Tony B's Avatar
 
City: Joe Wheeler State Park, Al
Country: Cruising/Live-Aboard USA
Vessel Name: Serenity
Vessel Model: Mainship 36 Dual Cabin -1986
Join Date: Jul 2011
Posts: 1,250
Quote:
Originally Posted by rwidman View Post
.........The easy way is to leave the thruhull in place and cap it off on the inside. .......
That is probably what I would do if it were me. I am at work and didnt have time to mention that. The little bit of drag created by the outer lip of the thru-hull is not worth the trouble to mess with. If you have never messed with fiberglass before, it is REALLY not worth the trouble and could possibly result in sinking your boat of you made a major mistake.
Fiberglas work is easy and with experience, you can actually work relatively clean. But one error in not knowing if the resin is about to set up or not could cause a catastrophic joint failure.
__________________
Cruising the Eastern U.S. Inland Waterways and Gulf Coast. Presently on the ICW in Louisiana and heading Back to Texas.
Tony B is offline   Reply With Quote
Old 04-26-2012, 08:10 PM   #5
Senior Member
 
jeffnick's Avatar
 
City: Spartanburg, SC
Country: USA
Vessel Name: Big Duck
Vessel Model: '72 Land-N-Sea
Join Date: Feb 2012
Posts: 425
If you are worried about the fitting protruding from the hull, consider one of these:

Jamestown Distributors
jeffnick is offline   Reply With Quote
Old 04-26-2012, 09:14 PM   #6
Guru
 
City: Full Time Cruising East Coast
Country: USA
Vessel Name: Meridian
Vessel Model: Krogen-42
Join Date: Aug 2011
Posts: 756
The reason I want it out is I need the space to put a holding tank.
meridian is offline   Reply With Quote
Old 04-26-2012, 10:13 PM   #7
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,922
I don't think you have to make the hole a solid laminate...you can still have it cored...you just have to epoxy a properly scarfed core in (depending on the core whether it can/shuld be done) then do properly scarfed skins on top and bottom.

But for a 1.5" thru hull...depending on overall hull thickness, I may just go solid...
psneeld is online now   Reply With Quote
Old 04-27-2012, 12:47 AM   #8
Senior Member
 
Capn Craig's Avatar
 
Join Date: Oct 2010
Posts: 418
I am just in the process finishing glassing in 3 unused thru hull transducer holes. I was my first hole patch, but not my first glass/epoxy experience. It was a time consuming but not hard process. My holes were about an 1 1/4 diameter thru an approximate 3/4' solid bottom. I followed the attached article pretty closely, with a couple of enhancements. Namely I put each of my round pieces of mat or cloth on a paper plate that had the diameter written on it. I sorted the smallest to the bottom of the stack for each hole, the largest, first layer applied was on top. I bought a nice but cheap ($18) digital scale, capable of 1 gram resolution from Harbor Freight. This proved to be the easiest method I have ever used for getting the ratios right on various size epoxy batches. I used clear plastic throw away cups for mixing. I put the resin and hardener in plastic bottles with ketchup type squirt caps. These let you add by the drop without waste or mess. About 6~7 drops = 1 gram. I would zero the scale with the cup on it. I would then add 3 to 7 grams of hardener, and then resin till the scale read 6 times the hardener wgt. Ex: 3g hardener = 18g total or 7g hardener = 42g total. This method is far more accurate than the WEST system pumps and allows you make a very small batch or a large one with the same accuracy. I presoaked the glass circles on their paper plates. I would do 5 or 6 at a time. I used slow hardener in approx 60 deg weather so I had time. I would stack the presoaked glass plates in order of application. Largest first. The best tool I found for saturating the glass and working out the air bubbles when applying the layers is a 2" chip brush with the bristles cut about a half inch long. The short bristles are stiffer and allow you tap out the air and move resin from place to place as you do it. I would pour the mixed epoxy on the patch circles like you would syrup on a pancake. I would then tap with the brush to get uniform saturation. The brush worked far better than the laminating roller. You are working upside down and air bubbles still want to go up. The short stiff brush did a better job of popping the bubles. For grinding the holes I used my 4 1/2 angle grinder with a 24 grit disk. It cuts fast. To control the very nasty dust I use an old forced air furnace squirrel cage blower. It creates a hurricane of wind. I place it so it about 4 ~5 feet from where I am working. It blows away the dust before it can land on you. Working with safety glasses in a short sleeve T=shirt I never got a bit of the itchys. Prior to ginding the conical holes, I groung off the bottom paint in about a 15 inch circle around the hole. Then use a template to draw accurate concentric circles every inch of diameter or so up to the final hole diameter (7.5" in my case) These help in getting the hole round and and the taper straight. I ended up with about 22 layers in each hole. My mat and cloth was pretty thin. One more thing, It is counterintuitive at least to me that the layers of glass run from largest to smallest. That is the right way though. It has to do with how the layers rest on each other rather than extend beyond the edge of layer below. This provides a stronger bond than having epoxy resin bridge the gaps.
Attached Thumbnails
Click image for larger version

Name:	hole patching.jpg
Views:	162
Size:	204.8 KB
ID:	11097   Click image for larger version

Name:	hole patching 001.jpg
Views:	126
Size:	196.5 KB
ID:	11098   Click image for larger version

Name:	hole patching 002.jpg
Views:	108
Size:	201.8 KB
ID:	11099  
Capn Craig is offline   Reply With Quote
Old 04-27-2012, 10:26 AM   #9
Guru
 
Tony B's Avatar
 
City: Joe Wheeler State Park, Al
Country: Cruising/Live-Aboard USA
Vessel Name: Serenity
Vessel Model: Mainship 36 Dual Cabin -1986
Join Date: Jul 2011
Posts: 1,250
A lot of the techniques are up for debate. Depends on whose rationale you like better. A start with the small disks first and work my way up. My rationale is that I have more bondings onto the hull as opposed to the larger one first. With the larger piece first, you are trusting your entire patch to the one piece. Again, it's up for debate so I guess either way could be correct.
My laminating technique is as follows: Always lay down a piece of visquene to cover your work surface - epoxy willl not stick to visquene. If at all possible try to figure out a way to have some kind of plywood or whatever covered with the visquene pressed agains the inside of the hull hole. This will allow you to press out and work the fiberglass from the outside without falling through the hole.
I use a roller and brush combination, but mostly a 'laminate roller". It is a hard nylon type of roller with ridges. This will press the resin (and the bubbles) out of the fiberglass after it has been saturated and thus prevent too much resin from being applied. I saturate each disk of fiberglass on the visquene, then use the roller to squeeze out the excess. Then pick up the piece and apply it over the hole. Carefully work it with the brush to spread it out as best you can then immediately apply the next larger size disk over it using the same technique as above.
The main thing you are watching for is that the fiberglass becomes invisible when wetted out. If any white at all is showing, it will have to be ground off before the next layer is applied.
Let the first 2 layers cure out over night. The next day you can grind it some and fair it out for the next three layers. I usually do 3 layers at a time, wait a few hours and add 3 more layers. I don't like to do more than a total of 6 layers per day.
Just continue the process. Glassing/grinding.
Got to get back to work........byeeeeeeee
__________________
Cruising the Eastern U.S. Inland Waterways and Gulf Coast. Presently on the ICW in Louisiana and heading Back to Texas.
Tony B is offline   Reply With Quote
Old 04-27-2012, 12:29 PM   #10
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
If you plan on doing this removal and patching yourself, you will need more instruction than what anyone can provide on a web forum. West System has books and a DVD (available at most marine retailers) that will guide you through the process.

What's important here, and what the folks are trying to tell you, is, you can't just fill a hole in your hull with epoxy (or anything else) and expect the patch to have the same strength as the rest of the hull.

Take their advice.
rwidman is offline   Reply With Quote
Old 04-27-2012, 04:51 PM   #11
Guru
 
bobofthenorth's Avatar
 
City: Cowichan Bay, BC
Country: Canada
Vessel Name: Gray Hawk
Vessel Model: Defever 43 Offshore Cruiser
Join Date: Oct 2009
Posts: 570
I filled a rougly 1.5" through hull hole during our recent haulout. Not knowing that I required instructions to do this I simply blundered through the project, as I have done for most of my life I might add. Family motto: real men don't need no stinkin' directions.

FWIW my blundering included dremel cleaning of the hole and roughening of the edges. Our hull is solid so no worries about coring. After the dremel work I taped a margarine tub lid over the hole from the outside. Then I thoroughly wet the sides of the hole with unthickened West System using fast hardener (it was cold out but above whatever magic temperature I found online for using West System epoxy). Because I was holding up the bottom paint crew I used a heat lamp to pre-warm the area and kept it on during the cure. I cut some pieces of glass cloth roughly in circles - maybe 6 or 8 pieces. For the outside layer I mixed some white pigment in the resin, put the resin in the hole from the inside of the boat and saturated a couple of layers of cloth in the pigmented resin. Then I changed to unpigmented resin and saturated the balance of the cloth that I had cut up. Then I filled what remained with resin thickened with colloidal filler. Then I went outside and realized that my margarine tub lid was allowing some leakage which I had suspected because I couldn't hold a level from the inside so I added duct tape and then added more filler from the inside. The effect of that failure to hold the lid tight to the hull was that my patch ended up maybe 1/8" proud of the hull which in hindsight was probably a good thing because I was able to fair it to the hull once everything cured. Which it did remarkably quickly because of all the heat I had applied combined with the volume of resin in such tight confines. So far it hasn't popped through the hull so I'm guessing that it may have worked out.

I love West System - I'm sure the other systems work too but West is the one I'm accustomed to. A couple of things I have learned though - first its important to wet dry areas with unthickened resin prior to doing any kind of bonding. That way the unthickened resin can flow into the voids and mechanically attach to the surface. Depending on the circumstances I have been known to briefly warm the resin in the microwave to further thin it to promote penetration (on really dense wood for example). Ideally if I have time I will wet the surface and let that coat cure before proceeding. I forget how many days you have to form a chemical bond to newly cured West System but if you do it within 24 hours it will chemically bond to the wetting layer. My second piece of advice is to buy the West System pumps. I keep a gallon jug of resin and a quart of each of the three hardners, each with its own pump. They live in a tupperware box in the engine room so that they are immediately and easily accessible without being able to make a mess. With the pumps you don't have to worry about getting the mix right.
bobofthenorth is offline   Reply With Quote
Old 04-27-2012, 08:03 PM   #12
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,922
It really isn't rocket science....jump in after a quick review of some of the basics...pracdtice a few small batches on other projects before your bottom if you have NO experience.

As far as the glass layers...remember it's only for strength not bonding...so it really doesn't matter to much as long as there's glass in there for a small patch like a thru hull hole.
psneeld is online now   Reply With Quote
Old 04-27-2012, 08:34 PM   #13
Guru
 
Tony B's Avatar
 
City: Joe Wheeler State Park, Al
Country: Cruising/Live-Aboard USA
Vessel Name: Serenity
Vessel Model: Mainship 36 Dual Cabin -1986
Join Date: Jul 2011
Posts: 1,250
Bob. I think you might have gotten lucky so far, but I would not be comfortable with that patch.
BTW, I only use West System epoxy. It is very consistent in performance.
I use the pumps also and I highly recommend them. I cant begin to tell you how much furniture I have repaired with West System.
If you ever take on a major project, i suggest to everyone to buy their videos. Their free technical info is also great.
__________________
Cruising the Eastern U.S. Inland Waterways and Gulf Coast. Presently on the ICW in Louisiana and heading Back to Texas.
Tony B is offline   Reply With Quote
Old 04-27-2012, 08:45 PM   #14
Senior Member
 
jeffnick's Avatar
 
City: Spartanburg, SC
Country: USA
Vessel Name: Big Duck
Vessel Model: '72 Land-N-Sea
Join Date: Feb 2012
Posts: 425
One More Time Around: Epoxy
jeffnick is offline   Reply With Quote
Old 04-27-2012, 08:51 PM   #15
Guru
 
bobofthenorth's Avatar
 
City: Cowichan Bay, BC
Country: Canada
Vessel Name: Gray Hawk
Vessel Model: Defever 43 Offshore Cruiser
Join Date: Oct 2009
Posts: 570
Quote:
Originally Posted by Tony B View Post
Bob. I think you might have gotten lucky so far, but I would not be comfortable with that patch.
Care to elaborate?
bobofthenorth is offline   Reply With Quote
Old 04-27-2012, 08:51 PM   #16
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,922
Quote:
Originally Posted by Tony B View Post
Bob. I think you might have gotten lucky so far, but I would not be comfortable with that patch.
BTW, I only use West System epoxy. It is very consistent in performance.
I use the pumps also and I highly recommend them. I cant begin to tell you how much furniture I have repaired with West System.
If you ever take on a major project, i suggest to everyone to buy their videos. Their free technical info is also great.
West is also the most finicky and doesn't wet out as nice as some of the other majors. A pro glass guy from Cape May and I were comparing notes the other day as he gave me advice about my bottom relamination project.
psneeld is online now   Reply With Quote
Old 04-27-2012, 08:58 PM   #17
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,922
Quote:
Originally Posted by bobofthenorth View Post
Care to elaborate?
For a 1.5 inch hole it's probably fine if I read your fix correctly...3 layers of glass on inside and 3 on the outside... with thickened plug inbetween. Not the strongest but it obviously keeps the water out. A direct hit on it may disloge it...but I would be more worried about getting hit by a meteorite.
psneeld is online now   Reply With Quote
Old 04-27-2012, 10:09 PM   #18
Guru
 
bobofthenorth's Avatar
 
City: Cowichan Bay, BC
Country: Canada
Vessel Name: Gray Hawk
Vessel Model: Defever 43 Offshore Cruiser
Join Date: Oct 2009
Posts: 570
I get more than a little tired of internet experts who try to make simple projects complicated. I've been messing with fiberglass for close to 40 years now & I still don't know much about it. What I do know is that for simple repairs - like plugging a 1-1/2" hole - its not rocket surgery and anyone who suggests otherwise is being silly or worse.
bobofthenorth is offline   Reply With Quote
Old 04-28-2012, 07:03 AM   #19
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,922
Quote:
Originally Posted by bobofthenorth View Post
I get more than a little tired of internet experts who try to make simple projects complicated. I've been messing with fiberglass for close to 40 years now & I still don't know much about it. What I do know is that for simple repairs - like plugging a 1-1/2" hole - its not rocket surgery and anyone who suggests otherwise is being silly or worse.
That's the beauty of the internet...if you go to it for advice...you certainly get the full spectrum of advice. You learn pretty quickly who are the guys with lots of book/forum reading and those that have been elbow deep in it for awhile.

So you pick and choose and verify the best you can...weight it carefully with your own experience and go forward. Sometime if nothing else to let a pro do it if you still feel uncomfortable and the fix would be expensive or deadly.

The best is when you say you did something that's barely on subject and you get blasted and the thread now is about how stupid you are...

The internet has definitely lessened my TV watching...beats the crap comedy shows they pass off today.

But even the armchair guys know a thing or two in SOME categories....
psneeld is online now   Reply With Quote
Old 04-28-2012, 08:07 AM   #20
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,390
Quote:
Originally Posted by bobofthenorth View Post
I get more than a little tired of internet experts who try to make simple projects complicated...............
I get more than a little tired of my neighbor's barking dog or the people flying through the neighborhood ignoring the speed limit and stop signs. The beauty of the Internet is, one mouse click will take you somewhere else or you can turn off the computer and go boating.

The OP asked for advice and that's what he got, advice. He got conflicting advice but that's to be expected on the Internet.

From my point of view, if this repair is below the waterline (he didn't say), I would follow the instructions that West System provides in their booklets and DVD. Doing this incorrectly could result in the boat sinking

I'm not going to get the book out and copy it word for word, but basically, it requires grinding out a large area around the patch and using several layers of fiberglass cloth and resin. This is to insure a good bond that won't fail and fall out.
__________________

rwidman is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 02:46 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012