During the early days of softball, wood bats were used. Due to the weight and size of the softball, it was common for bats to break. Also, performance was not optimal. Eventually, aluminum bats became the bat of choice for both fast-pitch and slow-pitch softball. Beginning in the mid-1980s, manufacturers started to introduce bats made of graphite and plastic. While these bats lasted as long as aluminum bats, balls were not hit nearly as far as the aluminum counterparts. Carbon fiber bats came out in the mid-1990s and initially did not perform as well as aluminum bats. However, by the new millennium the performance standards for carbon fiber bats met and eventually exceeded aluminum.
Rubber Batting Cage Balls
Many batting cages use heavy rubber balls instead of actual game play softballs. The majority of composite softball bat manufacturers discourage hitting these rubber balls with their bats. In fact, manufacturers will void the warranty on the bat if there is evidence that rubber balls were hit with it. It is recommended to utilize the batting cage's bats with these balls instead. The rubber balls are heavier and more dense than a regular softball. The added density and weight of the balls will create more stress on the bat during a swing. This can lessen the useful life of the bat or even cause it to crack and even completely break.
Breaking in Bats/Techniques
Softball players have a variety of techniques that can be used to break in a composite bat to improve its performance. A common technique is known as rolling, in which a bat is placed between two rollers. The bat is then moved back and forth while the rollers are pressed. This technique breaks the fibers which gives the bat more elasticity, causing the ball to jump off the bat quicker. Other ways to achieve this desired effect would be to use a vise or a rubber mallet. It could even potentially be done by hitting rubber balls in the batting cage, based on use of greater force to break the fibers. The ASA (Amateur Softball Association) will not allow rolled bats to be used in league play, as well as any other bat they feel does not meet its performance standard.
The ASA tests bats based on the 98-MPH standard. This standard states that the speed of a batted ball cannot exceed 98 miles per hour. Testing takes place by having an experienced batter hit a set number of balls. The balls are pitched the same style and are all of the same type. The speed of the ball immediately after impact is then calculated and averaged based on number of swings. Tests in 2007 and 2008 indicated that composite bats gained as much as 3.5 miles per hour of batted ball speed after 500 swings. This did not include bats that had been broken in using other techniques. When testing for performance, regulation balls are utilized as opposed to rubber balls. Rubber balls are heavier and more dense, and thus cannot replicate the game play simulation needed for performance testing.
Pros and Cons of Composite Bats
Composite bats made of carbon fiber are not as static as aluminum bats. Carbon fibers are weaved together to create the bats. Therefore, you can change the stiffness of the bat anywhere along the barrel, unlike an aluminum bat, which will be consistent throughout. Composite bats can be just as durable as aluminum bats while exceeding their performance. However, that durability comparison is only within actual game play. Aluminum bats can be used in a batting cage with rubber balls and are generally the bats provided by the cage owner. Another negative is that many softball leagues and associations are closely looking at the performance on certain composite bats. Thus, many of these bats cannot be used in league play depending on the association.