|Topic Review (Newest First)|
|07-08-2009 01:56 PM|
|ikrieger||I just did this on two of my thru hulls. I did it the old don casey way with about an 8 to 1 ratio of taper on the hole and 8 layers of new glass/matt alternating as i went. I used the smallest patch first then each layer was slightly bigger overlapping. Next time i'd probably do largest first because it was hard to wet out over ridges of smaller patches. I worked from the inside. started by grinding out the taper then sanded the outside edge of the hole and did a slight taper on that. backed up the hole with plastic on outside then put about an 1/8 inch layer of thickend epoxy, then laid my patches over that. lastly on the outside i used more thickened epoxy to fair then painted. I have minimal fiberglass experience but it was fairly easy. follow directions. Practice first on something less important if your not sure.|
|07-08-2009 12:49 PM|
This was useful:
Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Maine Sailing at pbase.com
|07-08-2009 10:23 AM|
Thanks for all the info.
One last question:
The old toe rails were in bad shape and removed. I now have many holes where the toe rails were thru bolted. Can I just fill these with epoxy thickened with 404/406?
Should I drill the holes slightly larger to get “fresh” fibers? Maybe angling the bit to flair the holes 1st, then filling with 404/406 would be better to give more contact surface.
|07-07-2009 05:38 PM|
|sailingdog||Also, when you're sanding the repair fair, the chance of abrading the largest, longest fibers, which provide the most strength to the repair are much lower if the largest patch goes first.|
|07-07-2009 01:23 PM|
as merc and US27 said the largest piece makes the most contact with the old glass. it also makes it slightly stronger by building in a curve in to the glass structure. look at it like a mini blind, the curve they put on the slats ( assuming metal or plastic ) holds them straight, not floppy. any structure with a compound curve is stronger than just a flat plane.
also if you ask me putting the larger pieces on first is easier, it helps support the repair. what i mean is getting a piece of glass that measures 4 inches to stay in place over a 3 inch hole would be hard, but a 6 or 8 inch piece will "hold" better when not cured.
the biggest trick to make it look good and get the most strength is when all the glass is in place and still "wet" put a piece of plastic drop cloth, trash bag etc. then squeegee like mad until you cant get any more resin out, then let it cure and after cure pull the plastic
|07-07-2009 11:46 AM|
What Scotty says, it refers to the hull thickness. on thick hulls I prefer making repairs from both sides since it makes it easier to fair in and finish afterwards.
With larger holes I'll use a plug cut from a coffee can lid taped in place as a backer. It's stiff enough to provide support, and epoxy doesn't stick to it so it's easily removed. They also work for pre-wetting patches.
Just don't do a 'repair' like I found on my Ariel:
Picasa Web Albums - ken - ariel
Picasa Web Albums - ken - ariel
|07-07-2009 11:18 AM|
I used to think this way as well. In fact, I used to think this way because I read instructions showing this method. The problem with using the smallest first is that the glass fibers are shorter. The fiberglass layup gets it's strength from the glass fibers. You want the longer glass fibers to be in direct contact with the hull for the longest distance possible. This will give you the best strength. Grind a taper around the hole on the inside as well as the outside and do the layup with the biggest patch first. If you do the inside patch first, you will have something to adhere the outside patch to. You can use a small piece of wax paper and a lot of tape to make a backer for your inside patch, then the inside patch will be the backer for the outside.
Originally Posted by WesterlyPageant View Post
|07-07-2009 11:02 AM|
I’d like to give this thread a bump. I’ve read and re-read the West manual on fiberglass repair. Very useful! I have an old transducer thru-hull that is empty (boats out of the water). I’d rather fill it and install a shoot through the hull transducer since I’ll be buying something new anyways.
My question is:
In the manual it seems like they advise cutting the first piece of cloth (the largest) to lay in the tapered area and come just shy of the lip of the taper, so it’s in the shape of a bowl. Then the next smaller piece dose the same and so on and so forth until you use the final and smallest piece of cloth to go in the center. This one would be nearly flat.
The photos they have in the West manual seem to mimic this, showing the largest piece of cloth going in 1st. I was under the impression that you ground out to you 12:1 and then start with the smallest piece of cloth matching the hole in the boat, and then work your way to the larger pieces of cloth finishing with the largest, roughly the same size as your taper.
Is this not correct?
|03-02-2009 12:05 PM|
|sailingdog||IMHO, you're better off repairing holes from both sides...since that will make a stronger repair generally. More work, but a better repair.|
|03-02-2009 11:23 AM|
|Keldee||I agree with scot.. and arf.. good points! Hubby says if you want a job doing well do it yourself but after making sure it is done right. We have closed several holes under the waterline and luckily could do them from the inside so that cosmetics wasn't too much of an issue.The important part is to as said read up and study the best way to do anything.As ARF145 says pros dont always do it right.Read read read!!!|
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