In the late 60’s and early 70’s when waterbeds first hit the market there was really only one type of waterbed mattress, the free flow with enough motion to make a sailor sick. It was simply a vinyl bag filled with water. In the beginning the free flow water bed mattress was more of a novelty item that merely sat on the floor. The evolution of the product has taken it off the floor and put it into various frame designs. From the simple Free Flow mattress it has transcended into a plethora of choices and levels of support compared to yesterdays simplistically designed free flow mattress.
If you shopping around for waterbeds you will be able to choose between various types of water mattresses that include materials to slow motion and increase support for your body. Materials used to increase the support for your body and slow the motion go by the following names: (Baffles, Foam, Coils, or layers of Fiber). The more of the material that is used inside the vinyl bag the quicker the motion stops. Strategically placing the materials offers additional support. Often they will be constructed of just one of (these designs) or a combination of these materials. The materials range from spun polyester fiber batting that is Thermal Bonded, Heat-sealed or Glazine finished. Often these have a tendency to break down faster when exposed to water. Resin bonded batting usually performs better and has a longer life when exposed to water.
Vinyl Baffles, Pod Baffles, Hydraulic Pod baffles- many names are used to describe them but they basically are all chambers constructed into different shapes used to slow mattress motion. They can be welded to the bottom of the mattress in different fashions to reduce shifting problems. Then assuming the chamber is a cylindrical shaped pod baffle design, It will have a vinyl encased closed cell foam top to the cylinder that floats to the surface exposing the slotted walls of the cylinder creating a barrier to slow motion. These are rare today and have many more seams involved in the building process, which increase your chances for seam failure. Some of these systems are free floating and reduce some of the stresses dramatically or completely. These are all rare sights in a show room today.
Often polyurethane foam is used; this typically gives the most motion control, however it does tend to be the least durable when exposed to water. Plastic coils that attach to a plastic sheet, much like a six-pack of soda is another way to control motion. These coils are sandwiched between layers of fiber to offer additional comfort and significant durability over other designs especially in the instance of a couple that is heavier.
One last note, some fiber layers can contain reinforcement that acts like rebar in concrete. The difference being that this material is constructed of a plastic mesh similar to an onion or potato bag but heavier and bigger. This mesh is woven into the fiber offering additional strength and long-term durability and reduces the nesting affect.