Is their a specific kind of mesh( you said tight mesh and thicker mesh) and epoxy I have to use? I thought I read on here that it has to be a certain kind. I have a west marine a block away from my house would you know if they have the stuff I need? They seem to have a lot of that stuff.
thanks
You're confusing the words epoxy and resin. Resin is what you use to laminate the glass. There are different kinds of resin: polyester, vinylester, epoxy. Epoxy is what you need to use, since the other kinds will delaminate from the hull.
Now, the type of epoxy doesn't matter so much. There are different kinds, and I don't need to get into them (such as pre-peg epoxies which must be baked). Almost all of the readily available epoxies will work. You simply need a viscous laminated epoxy resin that will fully cure at room temperature, and most will. I personally use a 3:1 laminating resin that fully cures at room temp and has a working time at 80 degrees of about 10 minutes, and about 30 minutes or longer at 60 degrees. Really it doesn't matter too much. The people selling you the epoxy should be able to tell you what it is for.
Mesh is your word, not mine. There are 3 different kinds of glass: Woven, chop/mat and biax. Woven is literally woven, like fabric. Chop is randomly arranged piece of glass strand. Biax is woven sewed to chop. Woven resists sheer. Chop resists impact. Biax resists both. Biax is the one that is considered "structural".
When I use the word "thick", I am referring to the weight. The weight is actually a measurement of how much resin the glass will soak up to be fully wet out. I don't use any science here, so I only concern myself with thickness. A 20oz cloth is going to be twice as thick and strong as 10oz cloth. (I use the word cloth interchangibly with fabric, as an non-specific type or weight of material). However, 2 layers of 10oz cloth will be stronger than a single layer of 20oz cloth. Heavier cloth is used because it is less work and faster.
Lighter weight cloth is thinner, and disturbs the body work less, which is the reason I say use thinner fabrics on the pissers. However, a single layer of 10oz cloth is not very strong, and may be insufficient for the exhaust outlet. I would suspect that a single layer of 18oz biax on the inside, and 10oz weave on the outside, would be sifficent strength to repair an exhaust hole (assuming you have layers of glass inside the hole, and not just thickened epoxy). This will certainly be plenty if you are covering a side exhaust with a sponson. You may want to use a little extra on the inside if this is a rear exhaust hole or a side exhaust with no sponson.
For patching your pisser holes, the areas is non-structural, and it doesn't really matter what you use. You can cramp a bunch of chop in the hole, cover it with some chop, do some body work and call the job done. It's probably never going to be a problem. The exhaust on the other hand will be seeing some abuse, and should be done in a method better than just cramming a bunch of glass into the hole and sanding it out.
Personally, I like to do my jobs all the same regardless of how structural they are. Even a simple pisser is done the same. I use biax for just about everything, and I cut it to fit what I am working on, such as a small circle to fill a pisser hole.
That is why I say to cut small circles, fill the hole with them, then cover them. On the pissers, I would only cover them on the inside (because otherwise it will mess up the body work on the outside), while on the exhaust I would do it on inside and out, since you need the added strength below the water line, and that's a pretty big hole to patch..
