It is very important to understand why proper vibrating of concrete is essential. Some reasons include increased strength and a better finish. Likewise, improper vibrating practices are both costly and dangerous.
The most common process of vibrating concrete relies on a skilled operator using an internal concrete vibrator, commonly called a pencil vibrator (as well as some NSFW - Not Safe For Work - names). There are numerous applications that require portable internal concrete vibrators due to proximity or access. There are also many instances where an internal concrete vibrator cannot be used, including when the internal steel or mesh reinforcement leaves little room for the vibrating head.
A terrific alternative is the use of external form vibrators. An external form vibrator is mounted to the outside of the form, either permanently or portably. External form vibrators are most typically powered by electricity or compressed air but there are hydraulic vibrators available as well.
As I stated earlier, internal concrete vibrators require a skilled operator. I always like to say, they require a skilled operator that is having a good day. Not an operator who might be hungover, sick, or distracted...one who actually shows up for work that day!
Rely on external form concrete vibrators and take inexperienced, distracted, or possibly careless operators out of the equation.
An external form vibrator simply does the job, consistently and efficiently, each and every time!