Epoxy (and polyester) 101 Fillets and filler:

T

thataway

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C Dory Year
2007
C Dory Model
25 Cruiser
Hull Identification Number
DOR25652A707
Vessel Name
thataway
I cranked out three projects in a few minutes--my appologies, but I don't take my high end Canon camera into the shop--so some the photos are not in good focus--but the idea should be there. Photos on page 7 and 8 of Thataway album:

I wanted to make a support for a fuel pump to transfer the 80 gallons of fuel I had removed from the C Dory 25 when we put in the new cockpit floor. I drilled the wood, and fixed the screws, before I mixed the fast set West systems epoxy. This is 5 min. epoxy I used, with filler if necessary for bonding items to the hull etc. You can hold blocks in place while this epoxy sets up--then glass over if necessary later. Great stuff, and much cheaper than the small tubes--see first picture.

The L bracket is coated with epoxy and assembled with two screws. I show pictures of the 105 epoxy and 206 hardner with pumps. Next photos of the various fillers I use most of the time--I have another half a dozen in my project box. The epoxy is metered, then cabosil added until it is stiff and will "stand" by itself. Then I add a pinch more of the microlite filler. This is mixed to a peanut butter consistancy and then spread in place. Since I am metering I had surplus, and then ran the tool--again a West Systems item which is reusiable. I clean my "tools" with fast orange citrus hand cleaner (one gallon size lasts several years for the hands and tools). After cleaning off the surplus, the fillet is ready to go, and allowed to set up.

Next I took a deck section I still had arouond this is from a 70's era Pearson 30. The cleat is fastened properly in plywood, not thru the balsa core--plywood is placed in the mold along with the 3/4" balsa core. Note that this 30+ year old boat has fullly intact balsa cored deck. The holes in the plywood were epoxy coated and well sealed.

I drilled a half inch hole right at the end and then extened it so you can see the under cutting with a Dremel drum sander. This makes a very neat cut about 1/4" deep, removing the balsa core. The balsa is replaced with the epoxy mix--this entire process took a couple of minutes--and should be included in the production line process for all thru hulls.
As you can see the sides of the hole are wiped clean with a popcicle stick and no more drilling or sanding is required for putting in a fitting of 1/2" size.

Finally I drilled a 3/8" hole in the deck--not thru the inner glass. I used a Dremel cutter bit to route out the inside under the glass. Then epoxy filler is placed into this hole and pushed back under the edges. When a screw is placed into this epoxy "plug" there is great strength and no possibilty of water intrusion--again the way that any item which sits in water or can sit in water in a cored hull shoudl be put together--how long does this take? Two minutes at the most. Very simple and very effective in preserving cored boats. If there is adequate glass on the top and bottom of a laminate core, and one uses these very simple techniques, cored hulls are very effective and will last a long time. Any short cuts can lead to premature failure.
 
For holes in verticles - say the transom - is your epoxy thick enough to
just stay in the hole, or do you inject it with the West System Syringes and
put tape over? I never know how thick to make the mix and have a tendancy
to head towards too thin.

Mike
 
Bob,

When you use the west system 105 resin and 206 hardener with the pumps, after you complete a project, can you put the resin and hardener away with the pumps still on the containers, or must the pumps be cleaned out and the containers sealed after each use?

If the supplies stay good over time after opening (unlike 4200 and 5200) a quart of resin might be reasonble. Otherwise I may need to go with something that comes in smaller quantities.

Thanks for entertaining these basic questions.

Rob
 
I often coat holes with layer of resin first, to get better penetration and adherance to the wood. I make the resin and filler mixture thick enough to stand up by itself. It will stay in a transom hole--you can tape if you wish (I put sarin wrap or mylar (release cloth is another option) under tape if using it. You can always thicken up epoxy, but never thin it. Often I will mix a batch of resin, then use the pure liquid for sealant and penetration, then add a little cabosil for thickening if I need to adhere cloth to the bottom of something, and finally thicken up to the peanut butter where it stays put--at the end. With a slow hardner and cool temps you are fine. lf it starts to get too hot, you can put the can in ice water (with ice in the water) to cool it down and slow the reaction until you are ready. Also the reaction is much faster in the container than when applied to the surface.

As for the cans, I use enough that mine lasts fine. I do not take the pumps out or clean them. I do use them fairly frequently with various projects. For some folks the System 3, which uses equal volume is a better answer, since it is easier to measure.

As for sealants they go into the freezer as soon as I am thru with them. Cover the ends with aluminum foil--usually when thawing they are fine, without cleaning out the ends. I find that if I leave the tubes or cartreges that they harden in the ends unless you keep them cold.
 
I've had cans of West with pumps in them for years. They last fine and
still work well. One thing to note: Don't buy the same size resin and
hardener. I don't use them often enough to recall which is smaller, but
you use much less of one than the other. To buy enough to make a
complete batch, one can is 1/5 the size of the other.

I didn't know that and have much more of one than the other!

Also, you probably don't need nearly as much as you think. For instance,
I'd bet that the fillet Bob showed needed less than one stroke of
each pump. Probably a lot less. But, unless you want to eyeball the
mix, that is the minimum you can make. It's not a lot, but when you
add the filler, it can bulk up a lot.

I'm just beginning with this. Need to learn to work with cloth, etc.

Mike
 
Right Mike--that was one stroke of the pump--I usually go with the full stroke, since I have been bitten by incomplete catalyzation a couple of times when I didn't mix enough--and I had filler left over. That is why I suggested the Systems 3 for people who only need a little--or the 5 minute West systems--both are 1/1. (edit: note that System three is 2:1 epoxy to hardner). There are a number of other 1;1 ratios.

You are correct that most hardners are 1/5th of the resin. The 206 is 7 oz vs a quart. A few of the hardners are 1/3--and there is a pump for these--they come in larger containers.
 
Most of the System Three resin/hardener combinations are 2:1, not 1:1 I believe. I've been using their products for 10 years, and swear by them. Particularly useful is their QuikFair, a two-part pre-mixed filler that is easier to sand than the usual cabosil (aka fumed silica)-based mixtures. Sets up in 4 hours to a sandable base, so you can get two rounds of filling done in a work day.
 
Thanks for the correction Dave, I have only used System three a couple of times and my memory failed me. You are absolutely correct. There are a number of 1: 1 epoxies but System Three is not one of them. The 2: 1 is still easier to measure.

You can make a filler any density which you wish using the various agents. The hadest is mill fibers (short glass fibers) with cabisol--the easiest is one of the low density fillers. It is also possiable to use a soft filler, then put a hard epoxy coat over it as a finish coat.
 
Did a bit of Googling, here is the best detailed description of how to fiberglass over plywood I found - naturally from Glen-L. It describes in considerable detail a four coat process - seal, bond, filler and finish coats. There appears to be a lot on this site, this is just one page. If anybody else comes up with really good links, by all means post them in this thread! Maybe as a first project, I will fiberglass over a little plywood Honda generator stand for the motorwell.
 
Pat,

While other manufacturers have good info, the WestSystem.info site has alot.

for info Phone - 866-937-8797, main site = WestSystem.com

1 - "User Manual and Product Guide" - covers safety, surface prep, bonding, coating, fairing, applying fiberglass cloth and more.

2 - "Repair Manuals" - "Final Fairing and Finishing", "Fiberglass Boat Repair & Maintenance", "Bagging Techniques", "Gelcoat Blisters", and "Wooden Boat Restoration".

3 - "The Gourgeon Brothers on Boat Construction" , 5th Edition


4 - "WEST SYSTEM Epoxy How-To DVD" - a compilation of three instructional videos, 59 minutes.


John
 
Depending on the job, you can do coating different ways. Many times if going with epoxy onto gel coat or polyester laminate, I just wet one side of the cloth, then put the cloth strip in place, and wet the other side. After it sets up, I smooth on a filler coat--with fairing compound, which blends in with the edges of the glass. What is described in the glen L link is for glassing a boat or it will work fine for a box, but there you will be laping the corners. Also they don't emphesize that there is a point where the resin is still flexiable, easily cut with a kife and can be trimmed--both the cloth or epoxy with filler. I often trim edges of cloth, or use a four in hand file to work edges with filler roughly at this stage, before the epoxy becomes "rock hard".

go for the project!
 
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