Filling a void in an encapsualated keel

[okawbow]

I noticed a small crack on the lower aft part of the keel on my Bristol 24. It was weeping moisture, so I decided to grind it out and see what was inside. I found a void about 12" long and 6" high behind the 3000# lead keel weight. It was filled with wet saw dust. I assume the saw dust was poured in to take up space when the resin was applied to seal up the keel. Above the void, is solid resin and cloth. I guess over the years, enough moisture got into the void to cause the water to freeze and resulted in the small crack.

Should I fill the void with something before I glass the hole over? If so; what would work best? I'm also wondering how to best patch the 6" x 3" hole in the hull. Should I try and get a fiberglass patch on the inside of the hole as well as grinding out the outside around the hole? The hole is near the bottom of the keel in a very solid area, and the boat would not sink if the patch somehow failed.

[skylark]

I would fill it with epoxy mixed with one of the following in order of preference:

fumed silica
wood flour
microballoons
sawdust

[Allan]

Here are some links on fibreglassing repairs that might help

http://www.trailersailerplace.com.au/forum/viewtopic.php?t=126&highlight=fibreglassing

http://www.trailersailerplace.com.au/forum/viewtopic.php?t=2943&highlight=repairing+crack

Allan

[okawbow]

I would fill it with epoxy mixed with one of the following in order of preference:

fumed silica
wood flour
microballoons
sawdust

I'm a little concerned about putting a gallon of epoxy in the cavity at once. Wouldn't that produce a lot of heat when curing? Is there any kind of foam that would work? If I do use epoxy, I have gallons of hardwood saw dust mixed with fiberglass, from my archery bowmaking machinery.

Here are some links on fibreglassing repairs that might help

http://www.trailersailerplace.com.au/forum/viewtopic.php?t=126&highlight=fibreglassing

http://www.trailersailerplace.com.au/forum/viewtopic.php?t=2943&highlight=repairing+crack

Allan

Thanks, Allan

[Allan]

Foam would work or you could use a block of timber coated with epoxy if all you need to do is fill the void before covering with matt and epoxy
Good luck with the repairs

Allan

[mrb]

okawbow

I wouldn't try to fill the hole in one operation, however I would use a mix as skylark suggested and mix up a small quantity at a time pack it in as tight as possible let that go of (start setting) then work up another batch and work that in.  Continue until void is filled then fair patch and cover with cloth, fair and finish.  The mix you are making will be thick thickend p-nut butter.

If you have never worked with epoxy you will want to follow directions closely.  Actually anyone working with epoxy needs to follow brand directions closely.

I find epoxy better nicer than polyester rosin in that if you get some on your hand it cleans up with soap and water.  I us liquid orange soap with the grit in it before letting water touch my skin then rinse with water.  Don't want to leave epoxy on to long though. 

Another option is to use a pre mixed bondo type filler.  I think its easy poxy makes a pre mix now with fiber glass strands in it.  Whatever want to follow directions closely as you can waist a lot if used wrong.

If you choose these meathods you want to feather edges out well but directions will explain that.

this is off subject so forgive me for mentioning it but as this is a new post and will get a lot of attention I just want to through it in.   Another post a week or so back asked for comments on a new boat that some one saw and there were a few post as be careful because being new they may be not so trustworth.  Now I don't want to imply that i have that much boat knowledge but it never ceases to amaze me how many quality boat names out there have some pretty bad short cuts in there building process.  Saw dust just does not have a place as a void filler in any boat. the only thing I can think of is that like the banking and mortgage people the owner hope the problem wont show up while the boat is under warranty.  Enough said on my part.

Best of luck on your fix and I have now doubt you will be successfully.
mrb

[okawbow]

MRB,

I've heard of all kinds of things being put into the encapsulated keels for filler and weight. I know that some of the early Bristol 24's (actually Sailstar Corsairs) had scrap metal and concrete in the keel. I think the builders just put in the ballast weight, and then leveled out the keel with whatever was handy before sealing it off with resin and cloth. I feel lucky to have solid lead as ballast.

Another thing I've thought of in this repair, is that the cavity extends back to the rudder pintle, which is glassed into the bottom corner of the keel. If I ever need to replace the pintle, I'm not sure I want solid epoxy in the way. Maybe I should foam that area?

[AdriftAtSea]

I'd highly recommend using a no-blush epoxy, like MAS, rather than West Systems, since you'll be adding layers of epoxy, and not having to worry about possible amine blush issues is a good thing. :)

[jotruk]

I had a bayliner buccaneer that had a lot of foam in the bilge and under the bunk. (found out that po had to patch a large hole in bow ) When I did extensive repair on bottom and bow the foam was wet and a bear to get out not to mention the stink. Foam will work good as long as it does not get wet and you have to redo the repair.Just my 2 cents

[Captain Smollett]

I'd highly recommend using a no-blush epoxy, like MAS, rather than West Systems, since you'll be adding layers of epoxy, and not having to worry about possible amine blush issues is a good thing. :)

It's my understanding that blush only forms after full cure...if you lay up layers before the blush forms, that is while the last layer is still tacky, there is no issue.

Charlie, can you clarify?

[CharlieJ]

That is correct. If you get the next layer or coat on while the first is still green there is no blush.

I have to agree with Adrift though- I'd not use WEST if for no other reason than it is SO expensive compared to other epoxies around. For the last several years I've been using  a 2-1 ratio epoxy from B and B Yacht Designs- cheapest I've found so far, by a good bit, and works as well as MAS, RAKA, or SYS 3.

One time I WOULD choose WEST is in cooler weather when I need something to cure quickly- the 5-1 ratio epoxy from WEST cures far faster to a working cure than any of the 2-1 ratios when the temps are close to 50. Usually by a day or two faster. I still keep some on hand just for that use.

And I've used WEST since 1977

[okawbow]

OK, I'm thinking I'll fill most of the cavity with closed cell foam, and fill the space behind the hole with wood flour, glass roving,  and epoxy. That way, I'll have a solid backing for the epoxy and roving for filling the hole in the glass. I don't want to leave any space for water to collect and swell again when it freezes.

Charlie, how far out should I grind the glass around the hole? The hull is about 5/16" thick there. Also, I have a couple gallons of Smooth-on epoxy I use for laminating wood and fiberglass archery bows. it is a 2, equal part epoxy with part A being the consistency of vaseline, and part B is like thick honey. Does that sound like it would work as a filler, mixed with wood and fiberglass dust? I know it is used to make castings.

I'll try and post more pictures when it gets warm enough to do the job.

[CharlieJ]

I always use at least an 8-1 bevel. 10 - 1 would be better. That would be roughly 3 1/2 inches of bevel, give or take- a bit more won't hurt.

The resin you have should do fine for the filling. Probably gonna be really hard to mix being thick like that, but if you have the resin-----

For the final layup of the fiberglass, I wouldn't use that. I'd get some B and B Yacht Design epoxy or I'd use some polyester. As long as you have a good surface, well ground, the polyester will work just fine.

Here's the web site for B and B and the phone number. Carla will answer. 252-745-4793

http://bandbyachtdesigns.com/

Lay up the first layer with a piece larger that the opening, then step each next layer down in size so they stair step in to the center as you progress outward. That way you retain the full adhesion of the first piece to where ever the bevel starts and ends.

[okawbow]

Thanks, Charlie

I'll try the epoxy you recommend. I have a couple other projects also, so I'll use it up.

[AdriftAtSea]

True Capn Smollett... but using a no-blush epoxy will make things easier if there is a problem doing the work and the epoxy ends up curing completely... :)  If you get called away in the middle of this type of project and have used West epoxy, you're basically screwed. :)

I'd highly recommend using a no-blush epoxy, like MAS, rather than West Systems, since you'll be adding layers of epoxy, and not having to worry about possible amine blush issues is a good thing. :)

It's my understanding that blush only forms after full cure...if you lay up layers before the blush forms, that is while the last layer is still tacky, there is no issue.

Charlie, can you clarify?

[Tim]

True Capn Smollett... but using a no-blush epoxy will make things easier if there is a problem doing the work and the epoxy ends up curing completely... :)  If you get called away in the middle of this type of project and have used West epoxy, you're basically screwed. :)

Screwed might be a little too strong a term don't ya think ;)
I mean all you have to do is give it a wash and maybe hit it with a piece of sandpaper.

[AdriftAtSea]

Depends on the size of the opening and how he is filling the void... if he can't get his hand in the opening the epoxy can be poured through... no, screwed is probably about right. :)  Also, cleaning the amine blush off of it and getting it all out is difficult if you can't get proper access to the area. 

[CharlieJ]

not to argue about the blush deal, although it's over done as something to worry about . But in this instance, filling a void, which will then be totally glassed over and sealed up, what difference can it possibly make if there's a bit of blush between layers?

Plus, you don't ALWAYS get blushing. Usually happens when working in a damp or cooler environment. In a hotter , drier environment, it's seldom a problem, although I make it a practice to always act like it is there and wash things down..


The epoxy I recommended is a no blush type. I told him about it because its currently the least expensive GOOD epoxy around.

[mrb]

MRB,

I've heard of all kinds of things being put into the encapsulated keels for filler and weight. I know that some of the early Bristol 24's (actually Sailstar Corsairs) had scrap metal and concrete in the keel. I think the builders just put in the ballast weight, and then leveled out the keel with whatever was handy before sealing it off with resin and cloth. I feel lucky to have solid lead as ballast.

That is true about the concrete and metal scrap.  That has been used for quite some time and many boats were designed from start for that method of ballast, more as an economy consideration especial in hard times.  I however doubt you will ever find any naval architect advocating the use of saw dust as a filler in any boat no mater where least of all the keel.  It would be nice to think that encapsulated keels would never take on water but that day is not here.  wood flower and epoxy mixed as a fillet is one thing. Saw dust is not wood flower and raw sawdust as a filler is just poor boat building.

[okawbow]

MRB,

I think that it was probably not " standard procedure" to put saw dust in the keel for filler. As you said; someone probably thought it would never get wet in an encapsulated keel. Actually, the sawdust was not rotting or smelly, and probably would never have caused a problem if the boat stayed in the water all year. It was the freezing and swelling of the water that caused a crack in the hull.

I have actually read where someone suggested using saw dust as filler to keep resin away from areas that might need to be accessed later. I think there are better ways to do that.


That is true about the concrete and metal scrap.  That has been used for quite some time and many boats were designed from start for that method of ballast, more as an economy consideration especial in hard times.  I however doubt you will ever find any naval architect advocating the use of saw dust as a filler in any boat no mater where least of all the keel.  It would be nice to think that encapsulated keels would never take on water but that day is not here.  wood flower and epoxy mixed as a fillet is one thing. Saw dust is not wood flower and raw sawdust as a filler is just poor boat building.