Retroglass wrote:
With all these new Fiberglass on the market. I have been wondering about the materials used other that just glass s glass / E glass. What is the scrim used is it glass or carbon fiber pre preg? What mat are used? What is the modulus of the glass pre preg?
The most popular
new glass fiber is called
Zentron (the link downloads a technical bulletin PDF file titled
High Strength Glass Fibers. Zentron is produced by
AGY, in South Carolina. In a nutshell, S2-glass is the same S-glass that has been on the market since the 70s, but with thinner fibers and more modern sizing/resin chemistry. However, much of the published technical information is vague. The woven cloths are claimed to be more unidirectional than in years past. More important for the rod designer, the woven cloth is thinner, allowing more flexibility on how the glass pattern is cut and wrapped on the mandrel. Details about fiber weaves are not published.
The bulk elastic modulus of S2-glass is 12.9 million lbs/square inch, just like the S-glass of old. This is roughly 25% greater than E-glass. The final modulus of the pre-preg is usually a secret. That value depends not only on the glass fiber, but also on how much of the pre-preg is fiber and how much is binder resin*. Zentron pre-preg is ~65-70% fiber (compared to 45-65% in classic glass). The net result is a substantial modulus boost of the cured composite (but still a pretty small boost compared to switching to any graphite fiber).
Retroglass wrote:
Tapers & wall thickness elongation of the material under load? What are we really paying for ? Color, clarity of material, design & construction? Why are some blanks 30 bucks, others go to 300.00 bucks, and everything in between?
What are we paying for? All of the above. Clear glass is readily accomplished, so rod makers either put pigment in the pre-preg or color coat the cured/sanded blanks. The wall thickness is easier to manipulate than in the past, so different tapers can be made. But why some blanks are available for so cheap, while others sell for nearly $300 is a bit of a mystery.
Tom
* The percentage of fiber in the pre-preg is called the
fiber volume ratio. For round fibers, the maximum fiber volume ratio is about 70%. There will always be some space between the fibers due to the round shape.