: Anyway I have a question of
: opinion that I would like to put to you. 2 questions really. When I
: ordered my fiberglass I was too new to consider any other than 6 0z. (I
: guess it's plain weave) E glass. Since I then have become aware of 4 Oz.
: satin weave (from this BB). I planed all the strips and have been
: fortunate enough to have a nice deck coming along now, is it worth it to
: change to 4 Oz. satin weave now, when I already have all the 6 Oz. to do
: the job ?

In the immortal words of Groucho Marx, "except for the improvement, she'll never know the difference". Before the trend toward lighterweight glass cloth there were an awful lot of boats built with 6, 7.5 and even 9 ounce cloth. They were heavier because of the thicker glass cloth, and the extra resin needed to fill the weave. tehy were also somewhat stiffer and somewhat stronger.

Going from 6 to 4 would save you 1/3 of the weight of the glass and resin. If you use 10 pounds of resin with the 6 ounce cloth, you'll use 7 pounds of resin with the 4 ounce cloth. Your cloth alone will probably will weigh in at about 8 pounds if you use 6 ounce fabric, and 5-1/2 pounds if you use 4 ounce. The total difference in weight is only going to be about 5.5 pounds. On a 40 to 45 pound boat design, you'll be the guy with the 45 pound boat, and not the 40 pound one. You can keep the weight down by only using one coat of resin on the interior areas under the decks. (no need to fill the weave here as no one will ever see them) This would actually be the second coat if you consider the first to be when the cloth is applied. Using a lightly spplied seal coat before putting on the glass will help to reduce your resin soaking into the wood, and save a bit there, too.

: Secondly and perhaps more importantly, I was very interested in
: GR's point about the "inferiority" of the technique of using one
: (or 2 even) layer(s) of glass and then a "fill" coat of say 4
: coats of resin and then a sand to just smooth it out for the final finish
: (less varnish, of course). He suggested that the epoxy alone is too
: "soft" to serve as the "final" finish. He suggested
: that a "sacrificial" layer of glass be put on the hull and then
: sanding down (into) this "sacrificial" layer of glass, leaving a
: "finish" surface of a sort of epoxy / glass alloy.

Usually when you talk about putting a thin layer of sacrificial glass cloth over a layup it is because the layer under it is of a material that fuzzes or frays if you sand into it. This would be something like Kevlar.

George also likes to use multiple layers of thin glass cloth so he can position them at angles to each other, allowing the varying orientations of the fabrics' weaves to add strength in all directions. I think this is an interesting idea. and I'll eventually try it. (Now all I need is a large supply of 2 ounce glass for my next project )

When you apply the resin with a squeegee, on the first pass the tool runs over the surface of the cloth, forcing resin into the fabric's weave, and pushing it into contact with the wood. When you pull the squeegee back, it scrapes up the resin which is still residing above the cloth, effectively leaving behind resin that is wqual in thickness to the thickness of the fabric. In this way the fabric acts as a depth gauge, keeping you from going too lightly in some areas (they look dry) and allowing you to thin down areas where the resin pools, drips or runs. If you don't get the resin thin enough with the squeegee, you get a few more chances to thin it out with your sanding. In this case you stop sanding when you hit the glass fabric.

If your sanding reveals small areas of exposed glass fabric, these areas will later turn clear when you put on another coat of resin, or varnish, or plyurethane. In fact, to make repairs you will always sand an area surrounding the damaged area to "feather" the edges, and this feathered area is an area where you go right through the glass and resin at a small angle, exposing the weave and all. When the patch is applied over this area it all disappears.

Only the outside needs to be finished smoothly. This is of course to reduce drag.

As for smoothing things easily, and with the least amount of resin: After the first fill coat, if you lightly hand sand (no power tools needed here) with a block of wood and some 100 to 150 grit sand paper, you will knock off the edges of resin which are sitting well above the glass fabric itself, but which appear to be the woven fabric. Just take a few light swipes with the sandpaper. Your second fill coat may then be all you need to kill the weave. you can test an area by using a finer sand paper. See if you can sand it down to a smooth surface without hitting the fabric. Use a light touch here. If it works, go on to your varnish. If not, then one last fill coat should do you.

Using the 6 ounce glass, if you should accidentally sand so deep that you nick a few spots, it will sti;; be thick enough to hold things together. Just by its thickness it is harder to hurt than the thinner fabrics.

Hope this helps.

PGJ