Test Yourself

I hope you found last month’s questions interesting, if not challenging. I found that in developing them my interest in the whole composites arena (technical, manufacturing, marketing, operations, and history) was revitalized. I find myself perusing magazines and books related to our industry. I spent time at an industrial museum delving into the history of fiberglass, then did a couple of interviews with some real “old timers”. All of this may lead to some interesting questions or articles in the future, but for now, on with the quiz. — Larry Cox, ACMA Technical Manager, lcox@acmanet.org.

1. What is the difference between a plain weave fabric and a crowfoot satin weave?

2. What is a thixotropic index? How is it determined?

3. Name three methods of converting continuous roving into preforms.

4. What was the first true synthetic resin?

5. Who was R. Games Slater?

Answers:

1. The plain weave is the simplest weave, made by using an over- and- under pattern, while the crowfoot satin weave takes one warp yarn carried over three then under one fill yarn. Plain weave fabrics are stable and moderately open so that resin penetration and air removal are good. The crowfoot satin weave fabric is pliable, and can adapt to complex contours and spherical shapes well.
2. Thixotropic is a term used to describe the rehology (flow characteristics) of a resin that allows it to resist flow when at rest, but which flows under force. This is often referred to as false body or sag resistance of a resin. The thixotropic index of a resin is determined by measuring the viscosity of a resin at a high rpm (60) and a low rpm (6), and dividing the low rpm reading by the high rpm reading.
3. Directed fiber preforming, Plenum chamber performing, and water slurry.
4. Leo Baekeland created Bakelite by mixing phenol and formaldehyde in the 1890’s
5. Dr. Slater was a chemical engineer hired as a consultant by Owens-Illinois Glass in the late 1930’s to find new used for glass. While trying to develop large glass blocks for building purposes (Games was also involved with pre-fabricated housing) a process to make glass fibers was invented. Dr. Slater went on to become the Vice president of Research and Development for Owens-Corning Fiberglass in 1938. He was key to the development of the fiberglass industry that we know today.