I was running a little short on 6oz cloth, and instead of shipping a bunch over, I went to a local boatshop and picked up enough to do the couple sitting on the racks.
I didn’t look hard at it in the shop, but when I was putting a layer on today I noticed that the weave of the cloth is wider and flat, compared to the E-glass that I normally get from Fiberglass Supply. The color seems a little different to.
Just from doing the board today, I noticed that the cloth seems to wet out a little quicker/clearer than the E-glass, tucks nicely and even takes just a bit less resin. Looks like the hotcoat will take less resin too because there is litte weave texture left comparitively. I am going to do a colored resin board with it as well and see how it turns out.
I found, on fiberglass supplys website, that there is a flat weave volan, though I am sure that this is not volan because there was no green tint, a nice clear white look to the board.
I am going to call the boatshop again and find out what finish the glass has and what else they might know. …the only real pain is that it is 60" wide, so you have to cut it in half.
All that aside, my question to all of you, is what differences in strength does a flat weave cloth have compared to the regular weave? If any?
Probably no difference in practice although strength is related to the “crimp angle” wherever one tow of cloth passes over another in the weave. Fibre volume fraction is more inportant. Unidirectional cloth (no weave) fails at a higher load than equivalent woven cloth. For the weight of cloth you are using the effect will not be noticeable on a surfboard.
You might want to check on what kind of finish the glass has. While Volan can be used with either polyester or epoxy resin, some Silane is only for epoxies, other only for Volan, and still other can be used with either.
All other things being the same, like weights, resin, lam schedules, etc. and a standard foam and fiberglass board…
There is a huge difference between flat weave and twist weave fabrics and how they laminate and how they impact the function of a board.
Twist weaves work like springs and are can make a board more flexible. The twist allows the glass to wrap around compound curves easier. And the twist helps hold the perpendicular strands in the weave. They hold more resin. They need a thicker hotcoat to cover the tops of the yarns where they stick up as they pass over the perpendicular yarns. Good laminators know how to pull twist weaves tight creating a pre-stressed glass jobs.
Flat weaves are more rigid. Make a thinner lamination. Hold less resin. They lay flatter. They require a thinner hotcoat. Flat weaves don’t stretch much so they are difficult to pre-stress like a twist weave. They don’t hold in the perpendicular yarns in place very well and are more hard to lap tightly around curves.
There are probably some other issues or differences I have forgotten to mention here, but this should get you thinking.
Boards glassed with flat weave are more prone to buckling because the weave won’t compress much. When under tension the weave won’t stretch much and will fracture.
On a wooden board or a compsand, the glass becomes somewhat less significant to the whole because there are more structural components helping to support the stresses the board experiences. In a standard board, most of the stresses are handled by the skins making the fiberglass pretty important!