Fibreglassing

[Andrew]

I know...I know...I'm getting waaay ahead of myself again, but I'm pricing up how much this boat is going to cost :shock: .

I seem to recall that Phil put a heavier fibreglass cloth along his keel (24oz??) to reinforce it.

I was wondering if the heavier cloth is worth the cost (small as it is), does it provide any more protection? and if it does would anyone have any comments about a stainless steel fairing being epoxied to the front of the keel and then fibreglassing over the top of this?

I realise that the fairing is probably a little 'over the top' :roll: but being the landlubber that I am, I worry that if I damage the keel front then the whole keel may need replacing if water gets in there :cry:

Maybe I can turn her into an 'ice-breaker'? that could come in handy in a couple of months in Canberra

Thanx

Andrew

[ken connors]

andrew, months ago i picked up a huge roll of 18 oz glass w/mat backing on ebay for about 80% less than retail. when i announced my "score" at the byyb site,( i wasnt aware of this site) i got jumped all over as being crazy. i was grateful to all as it was merely accounts of individuals recounting their results. all well meaning , of course. i guess some have had bad experience with such a thick cloth. they are probably right, but now that i have it im going to try small sections at a time to see how it goes. it will need a lot more epoxy to saturate it properly, but as i see some considering adding ballast, maybe this extra weight down low may be good. i am currently being delayed from working on my vac. because i am repairing the chines of a dory-skiff i built 7 yrs ago because the 6 oz cloth tore in several places :cry:

[Robert Cox]

Save yourself the trouble and expence of using extra fiberglass or other exotic materials to protect your keel. Spend $20 for good oak 1 x 2 and put a sacrificial rail on the bottom of your keel. It will take the brunt of damage when grounding, beaching and that occasional misalignment when loading on the trailer.

If you ever wear it out (doubtfull) you just replace it. One thing you must do though is sink plugs into the keel with epoxy to seperate the mounting screws from the keel in case of water leaking around the screws. Mounted mine with 3M 101, #8 x 1 1/2" stainless screws counter sunk and wood plugs to hide the screws.

Living in Florida with all these white sand beachs, I have every intention of beaching a lot. I wanted more protection than you can get from fiberglass, kevlar or carbon cloth and paint. Plus, even if you can protect it using the cloth, you still wear the paint off. This way, I won't even worry about the paint.

Just my .02 worth.

Bob

[Barry Pyeatt]

Yeah, you really are getting ahead of yourself at this point. Got finishing fever and you havn't gotten that first cut out of your system yet.

Here is my take on glassing the Keel.

If you glass it and it gets damaged slightly you probably won't do anything to fix it. And then the potential for bigger problems presents itself. :cry:

If you are beaching on sandy beaches it is one thing. Mud flats another, and rocks an entirely different set of issues.

I personally would want to see the damage immediately if there is any. And repairs with epoxy wood fillers and a fresh coat of paint are a breeze to accomplish. Now on the other hand, if you have to take off the glass at the damaged area, fill, reglass, fill and then paint again....lets see, sail time or repair time....hummmmm! :idea: :arrow: I'll take the Foster's and head for the water anytime. :wink:

The sacrificial strip of Oak along the bottom edge of the keel as Robert suggests is just the ticket as far as I am concerned. Easy, simple to do, effective and it works. 8)

I am putting 3" kevlar tape on mine with two layers on the front of the keel/stem because we don't know what sand is here in Puget Sound. We have granular particles ranging in size from a large grain of coarse sand to monoliths. All of them are tough on keel bottoms. And I've seen boats with both oak and with kevlar. Both work. I just like the kevlar personally. Then just paint it. :wink: But that is my circumstances and yours are probably different.

[Frank Hagan]

andrew' date=' months ago i picked up a huge roll of 18 oz glass w/mat backing on ebay for about 80% less than retail. [/quote']

If you're using epoxy, you have to test it first. From what I've heard, glass with mat backing has to use polyester or vinylester resin in order to melt the binders in the mat portion. I don't have any direct experience with it, but I've heard that epoxy won't melt the binders down, and you end up with a mess.

But testing is easy. Even if you can't use it with epoxy, its still a "score", because you can use vinylester with it. More waterproof than epoxy, more flexible, and very, very strong.

[Denis Goyette]

Enlight me my good people .

Where does this strip of oak is going??? On top of the keel then fiberglassed or is it put on top of the finish keel? :?

Denis

[Greg Luckett]

Denis,

I believe it should be on top of the finished keel to allow it to be sacrificial.

Greg Luckett

[Barry Pyeatt]

Denis,

Yes...finish the keel and after you are finished, you will bend the Oak strip down the length of the keel and wrap it up the front of the stem to some point. That point needn't be all that far up the stem since it is supposed to protect the keel on beaching and bumping into the rocks and docks. If you tend to stop the boat by impact, as is fairly common place with some boaters, you may want to have it extend further up the stem and make it a little wider than a 1X2. But remember it is a very hard wood and to bend it around the front curve of the stem it will probably need to be either steamed or kerfed (which defeats the purpose of being there in the first place). That portion of the strip that has to take the tight bend can be soaked in hot water overnight or until it begins to be a little more flexible and then it may allow you to bend it, but the risk is that it will break trying to bend it. This strip should be the straightest grain, quarter sawn or vertical grain you can find, wild grain will be more likely to split. I would also agree that you would want to place plugs along the keel where you are planning on attaching it with screws. You would drill out a hole the same diameter as a short length of hardwood dowel and epoxy the dowel into the hold and when completely cured, drill your holes to attach the strip, I would recess the screws just below the surface so you are not rubbing the screws against anything.

[Phil Gowans]

Yes, I used the heavy 24-oz. cloth recommended for stitch and glue to protect the keel bottom. It is not a mat, I've also been warned not to use that. I also used it on the chine edges. Then I painted on a few coats of graphite / epoxy mix. I wasn't quite sure about this step, but some driftboat builders recommended it.

I originally launched in late 2000, so I've had a little over 2 years on the boat. This spring it was time for a good "dry dock" inspection and some maintenance. The tape had started to separate from the stem at the upper edge. It looked pretty ugly. I filled that with some epoxy - you can't even tell it was done now, except for the shiny spot of graphite there. I have beached the boat lots in sand, mud, and gravel and even banged into some rocks. Our shores on many reservoirs are quite varied. I have left her beached for up to 3 days at a time.

The report: During the inspection I found a few gouges on the keel and the worst section on the very bottom it had worn away all of the graphite coating, but there was no exposed wood anywhere. I used the 24-oz. cloth because I had it (this was before I had heard about using kevlar). I was very impressed with the way the keel had held up. I was very glad I had gone to the effort of doing this. In fact it really wasn't very much effort and I had the epoxy and cloth so the expense was nil. It was easy to fix the gouges. A little sanding some thickened epoxy and a new coat of graphite - As good as new.

I considered the sacrificial strip. I'm glad I didn't do it. I sometimes sail in the Great Salt Lake. For those of you who think you are salty sailors, you have no conception of how much more concentrated the salt is here. There is more than 10 times the salt in the Great Salt Lake than the ocean. For this reason, I did not want any metal (screws etc.) in the hull.

Here's a picture of the bottom. The brown redish brown is the color of the micro-balloon filler. The white scrapes are just that "sanding" with a paint scrapper. The black is not shiny now, more of a dulled black. It still looks good though and there is no need to paint.

[Robert Cox]

Andrew, if you look really, really hard you can just make out the sacrificial rail on the bottom of the keel. If you can make it out, you'll see it doesn't come up the stem far enough to be seen above the water line. It's just high enough to protect the keel.

I'll see if I can't get a better picture tomorrow.

Bob

[Barry Pyeatt]

Only had one experience in the Great Salt Lake. We just had to swim in the lake and experience it. Amazing that you can float sitting up. I understand it is a real terror on boats and hardware. I can fully support the stitch and glue approach for that local.

[Robert Cox]

Andrew, here's a shot of Knut Garshol's Weekender while upside down. The rail is quite obvious in this picture. Knut and I both had to put kerfs in the rail to get it to bend around the curve.

Bob

[Simon]

Hey Phil, I really like the idea of the graphite. What ratio of graphite to epoxy mixture did you use? Where did you source the graphite from?

[Barry Pyeatt]

Andrew,

You had asked about placing a stainless strip along the keel/stem and forming it around the edges.

We used to do that commercially with some river boats and had large plates formed to protect the flat "landing craft" type bows and bottoms from the rocks in the rivers. We also had strips fabricated for some keel boats that we worked on. Honestly, it isn't worth it. I would stick with Oak or Kevlar.

[Andrew]

I'm certainly glad I asked... I feel like I must be on the right track (still haven't made the first cut yet - the wood arrives tomorrow!!)

Most of my sailing will be in fresh water - with the odd trip to the coast, so the external oak rail appeals

[Phil Gowans]

Simon,

I don't remember the mix ratio. I know the first time I put it in I used lots more than called for and it worked fine. I usually mix it like I do cabosil. I think the only danger would be using too little that it wouldn't provide the UV protection. I got my graphite from a fellow boat builder. He just gave me some. I is just a fine power. System 3 sells it and here's what they say in their book:

White paste pigment (titanium dioxide)' date=' graphite powder, and aluminum powder are generally used by boatbuilders as pigments. Graphite powder added at high loading levels (25%) to coatings which are then sanded is claimed by some to produce a "slick" racing finish due to the lubricating qualities of the graphite. We have no data on this and caution potential users to be aware that graphite is a conductive material and could cause electrolysis problems under the right circumstances. Addition of small amounts of aluminum powder will produce a gray epoxy and in larger amounts will improve the machineability of the resin. Adding white paste pigment produces a white resin coating that is useful for bilges and other areas where a light color is desired and painting is difficult. Pigments aren't meant to serve as substitutes for paint in areas exposed to strong sunlight. White paste pigment is useful when added to the final fill coat when fiberglassing, allowing this coat to serve as a cover coat for finish painting.

Our other pigments are pure dry colorants ground into epoxy resin to produce an epoxy paste pigment. Since they are dispersed into epoxy resin they may be added to the resin side of our epoxy systems to produce a stable pigmented resin. The amount of the pigmented resin is used to determine the amount of hardener required. Used in very small amounts these pigments are transparent in an epoxy and can be said to act as dyes. In larger amounts they are opaque.[/quote']

[Denis Goyette]

Does the rail extent all the way to the stern???

[Simon]

Thanks Phil, I guess the UV won't be so much of a problem underneath the boat - it looks pretty swish as well. Did you guess the waterline, or is there some technique used to work it out? 8)

[Barry Pyeatt]

Denis,

Typically the greatest amount of damage if any occurs will be in the first 3-5 feet of the keel, but consider that you are taking it on and off of a trailer and it does get banged around some. So...most of them that I have seen cover the entire length. But I also have to tell you that most of them that I see are on drift boats and they often get dragged up on the rocks completely out of the water and moved into and out of trucks, and all manor of trailers.

Personally, if Oak were my choice, I would apply it in sections of about 4-6 feet in length so if and when it comes to replacement, I can replace a shorter section rather than the entire strip.

[Robert Cox]

The rail on Knut's boat goes to within a couple of inches of the stern. Mine is 8 inches short of the stern do to using a balanced rudder that goes 6 inches past the rudder box hinge line. There is really no reason it couldn't go all the way to the stern and this is what I would suggest but where you'll need the protection is toward the stem.

Bob