Fiberglass type

[Tim Mertinooke]

In the past I have alternated between mat and either woven roving or cloth when laying up fiberglass. I read recently that if you are using epoxy which I am (West) you don't need to alternate because the layers adhere so much better than polyester resin. I purchased Mat, woven roving, and cloth just in case because it is a good hour from the nearest source from where I live. The hull is about a half inch thick so I anticipate about fifteen layers of glass. The diameter of the repair is seven inches. Advice from those who have been there will be appreciated.

http://www.mrmert.com/ariel24/images/keel%20bulge/flush%20keel%201.JPG

[ebb]

Tim,
I extensively use Knytex X-mat. I began using it because mat and roving is exclusive to polyester. I'm exclusive to 100% solids epoxy. This is one of those 'unidirectional' fabrics that is stitched together with chopped strand. It is easy to cut and pickup and place in position. Wet or dry. It does not deform like woven cloth.

The X-mat has the unidirectional glass at 45degrees to the run of the cloth. It is docile, fabulous for one shot tabbing (like bulkhead to hull), you can poke this heavy fabric when it is wet into corners with your brush or spreader and it will like to stay there. But you can't mess around with it like cloth because it'll start to pull apart. I do make full size posterbord patterns for nearly everything - and trace it to the X-mat. Some laminators will pull at the X-mat and stretch it to get it to conform to a compound shape. I prefer to cut darts in it like a tailor does to serge.

It's heavy weight stuff, meant to build up laminate in hand lay-up. I can't remember right now but I think five layers of 24oz X-mat is about 1/4". Comes in 19 oz too, which doesn't gobble up the quarts of epoxy quite as bad. When dry it has a rough texture. I would not use a West System epoxy that blushes. X-mat can be used with all three resins.

It is equal in strength to cloth, so I've heard. One guy said he figured one layer of 24oz was equal to 7 of woven. I assumed he meant 10oz. But I have not read comparisons in plain english. Boat-builders use it structurally. It's strong and it wets out well.
I feel that I can sand/grind down into it and not loose integrity if I need to because it is not exactly a cloth.
Single layers of 19 and 24oz will set clear - you can see what its covering like cloth. It's not 6oz stitch-and-glue doodah - it's much thicker and has texture when set. Can always fill the weave with epoxy gel, and/or sand it down.

On surfaces with holes and imperfections, I'll bridge the surface with epoxy gel and place the X-mat right on top DRY and then carefully wet out a smooth no-void surface using a spreader. Magic. AND it doesn't drip or run - seems to hold the resin.

Another action is to wet-out the X-mat on some vinyl film and just peel it off like wet cardboard and place it where you want it. It'll hold its shape if you're careful. Not like cloth. If it won't hug to a compound curve, just take the shears and cut darts in the wet material. I write reminders all over the dry stuff with sharpies - dotted lines for corners etc. Love X-mat!

[bill@ariel231]

the good news on mat/roving or mat/cloth is the quick build up in depth over just plain cloth or just plain roving.. It's cheap too...

These aren't high tech or high stress hullforms; any technique you can imagine will work if the materials are good.

[commanderpete]

I would use what you have, but first check that the mat is the kind that is soluable in epoxy. The mat and roving do soak up huge amounts of epoxy.

It's going to be a little tricky since you don't have any backing to lay the glass against.

I'd be a little wary of laying the glass up against the lead. The lead may continue to migrate, despite your other efforts. Maybe try to leave a gap for movement, even if you have to chop the lead back some more

[ebb]

You can find plain glass mat at twice the price that you use with epoxy. Regular mat has a binder in it that only the esters will dissolve. Most roving is good with all resins. The 45 degree double bias fabric mentioned above is a true revelation at a reasonable price - you'll never go back to the old stuff. It's already layered for you - and you don't have to orient the material. Seems like there should be other sources than Corning (Knytec) for sewn/layered mat made on the bias. That's the secret that makes it so handy.

[Tim Mertinooke]

That crucial initial layer can be tricky in an application like this where inside access is merely a wet dream. This will be done per Don Casey's instruction from his Sailboat: Hull and Deck Repair book. My plan is to:

1. Clean with acetone and sand the back side of the hole's edge about 1/2 inch in to prepare it for adhesion.

2. Cut out a section of fiberglass cloth to the profile of the repair only slightly larger in diameter, say 1/4 of an inch.

3. Saturate the newly cut glass glass and allow it to fully cure.

4. Once cured remove the amine blush and sand with 80 grit so the subsequent layers will key in and so that it adheres to the back side of the hole in the hull laminate effectively.

5. Place two small screws into this new layer and attach copper wire to each screw making a loop.

6. Apply thickened epoxy to the outside edge of the newly created layer that was prepped to do so.

7. The cured glass should be flexible enough to bend slightly so I will carefull bend and manipulate it into the space between the lead ballast and the laminate.

8. the wire loop will then be pulled which will attach the newly created laminate to the back of hull laminate that was prepped to do so.

9. The wire will then be attached to a pole or broom handle tapped into the ground. Tension will then be able to be adjusted so that the edge is in contact with the back of the hull laminate, but not so much that this new layer will be warped. Once this has cured I should have a nice smooth layer to work from that will allow the 1/2 inch space between the hull and ballast to remain and be strong enough to withstand the force needed to apply subsequent layers. I have not done this, but when I read about it ceratinly applied to me and the idea made perfect sense.

This part of the plan I have had in my mind for a while and can picture it perfectly. It's the subsequent layup that is perplexing me due to the literature I have read, my past experience, and the plethara of new methods and materials. Go with a tried and true method with the materials I have at hand or wait a while while my new higher tech materials get delivered. I am in no rush as this is a very important repair, but am anxious to get started and would very much like to use what I have if possible. Ebb I do appreciate your advice on materials and experiences, this type of wisdom is seldom found in literature. I have this week off (not that the weather is cooperating) and was shooting for this weekend to do this. I don't mind waiting to order and receive the materials needed (X-Mat), but if using what I have will create a repair that is acceptable by virtually all that follow its progress (assuming I am careful and do a good job which I will) would using the traditional materials such as mat, roving, and cloth work?

BTW-the mat that I purchased says it can be used with epoxy so I am assuming the glue used will be compatible with the epoxy (west.)

[bill@ariel231]

Tim

good luck dodging the rain. today's temperature will let you fiberglass once the rain has calmed down. Heck, I'm on record doing fiberglass work surrounded by snow drifts using a heat gun to warm the repair until the fiberglass cured. It's amazing what you can do with a couple cups of java while the travel-lift is waiting...

cheers,
bill

[ebb]

Tim,
Are you plugging the hole - or trying to span the hole?
If you are plugging it, mix up some epoxy,
mix some cabosil (or generic fumed silica) into the liquid until you have a gel,
get the hole wet with epoxy,
fill the hole flush. BAM!

You can mix some chopped strand into your gel,
(I usually put it in befor the silica to make sure it wets-out.)

After it is set, dish it out with the grinder,
(this is a mild dish that doesn't make the original hole any wider.)
If the hole is two inches diameter, make the edge of your dish five or six inch diameter Don't go too deep. You can always grind it deeper.

Make a series of concentric disks out of glass fabric, doesn't matter what,
The smallest disk goes in the dish first on top of the original wound. (which is now filled and hard.)
Then add a series of larger disks so that the largest is last,
this is the one you will grind fair to the hull,
if it is not fair, you add some more epoxy filler. Try out the sandwich dry first, add or take away. Paste them in.

This thing with the wire sounds weird to me. Why?
OK, so you think you want to span the hole? Do it with a frp disk that you trim to fit and glue in.
If the hole is small, use a disk of wet out 24oz Xmat, and merely paste across the hole and let it set up.
You can always use blue tape or carpet tape to put a piece across the hole, grind it off when set.
If you have to span the hole, stuff some bronze wool in it.

But why are you spanning the hole? Lead metal doesn't care. Unless you are doing this to drain the space later for filling with resin. I don't think it matters. Just throw some epoxy at it!

Wets System makes some epoxies that don't normally blush. Use a laminating epoxy with a SLOW B side. You don't ever need fast or medium hardner. imco When you are finished with the West System buy a better epoxy! One with NO solvents or fillers in it.

You don't ever need to use acetone. There certainly is no wax left on the bottom of a 40 year old Ariel. Acetone will drive wax or oil INTO THE LAMINATE anyway. Don't use it. Use Joy Dish Detergent and water to clean a surface or to remove blush.

By the by, I think it is dangerouse to have a loose, unsupported ton of lead inside the keel.

[Tim Mertinooke]

In a former life I ran a sailing school and had many dates with epoxy repair, mostly filling, but occasionally laying laminate. The repairs were mostly from collisions. The epoxy they had on hand was West System so that's what used, learned on, and became accustomed too. When I rebedded the hardware and installed opening ports on my Typhoon last year I had a need for epoxy so I bought a quart of West because of my history with it and the fact that it was readily available to me. While doing research on materials to do some of the projects ahead of me on A-24 I searched the archives here and on other forums. I ran across a post from the Classic Plastic Forum discussing brand preferences. I went into this research with the ability to be easily persuaded in terms of epoxy brand as I have had a limited experience with it and only with one brand. To my surprise I ran across a posting from the guru himself T.L. I place a lot of stock in what he says for obvious reasons and following passage is from a posting he made. This did it for me, that's why I bought West System.

"I certainly put far more stock in the technical expertise of the Gougeon folks, their research and development, tech support, long-standing reputation, and the widespread use of the West System product by all high-end builders, than in the unsupported rantings found on certain websites that profess to have all the answers on epoxy.

Personally, I love West System, and it's now the only epoxy I use. It is the most consistent in performance, and there is substantial research, development, and product support behind it. Not only that, but the product was conceived for the marine industry, and is therefore optimized."

[ebb]

You can get used to anything. W.S. does have an aire of tech about it. There is however no excuse for selling to amatuers an epoxy that blushes. Epoxy is a top of the line glue. A little more expense for a top of the line product with your company name on it won't knock your profits. W.S. doesn't have to adulterate any of their stuff, they seem to do it because it's cool and makes them money. Why else? (That's why I'm incensed because I'm being cheated.) There are other well known straight-shooting marketers of great epoxies with sterling reputations that make laminating epoxies you don't have to wash.

Now, what I say there is based on experiences from long ago. It's based on other people's more recent experiences. And it's based on one person's revelations on epoxy formulations - and that some smaller companies have no blush as the only epoxy they sell.

If T.L.'s quote there was made in a media context, I would think twice about it. It's suspect because it's flat out advertising and like those actors on TV wearing white coats with stethoscopes around their necks, they are getting paid for it. And because T.L. has made a bit of a name for himself, it seems pretty blatant. If those quotes were made innocently in conversation, maybe even in a small semi-private forum context such as this one, then you can forget about it because it's just his opinion. It's B.S. Based on decades of honest experience.

So you see where I'm at in this. It depends on how the guy represents himself and how others perceive him. Those quotes are a prime example of how some people on forums sound like geniuses.

It's better to make your own mistakes than learn by repeating the mistakes of others.
T.L. can be forgiven, I suppose, because his writing style is one of total honesty. He isn't an expert but a man of experiences. Gougeon Bros have written great manuals on fiberglassing, but that doesn't mean their epoxy should go unchallenged.

"Whenever you find yourself on the side of the majority, it's time to reform." M.T.

[Tim Mertinooke]

The context of his statement can be viewed by clicking here (http://triton381.com/forum/viewtopic.php?t=942&highlight=epoxy).

Ebb, I appreciate your wisdom. I am but the Padawan and you the Jedi Master. West it is for this round because I have a gallon of it in my barn. When it comes time for the impending recore job down the line we'll chat more about the choices at hand :>)

[Tim Mertinooke]

Looking at the weather, it looks like I'll start the project on Friday. Pictures will follow of course. Thanks for the perspectives and ideas they helped.

[ebb]

May your padawan and your padatwo always be in correct proportion.:D