Most individuals’ experience with foam usually comes in the form of a couch cushion or a mattress topper. While some people think foam is made directly into these shapes from molds, the majority of foam products, including comfort products, are actually manufactured from bulk forms called foam buns.
This name is apt, due to their appearance being similar to a gigantic loaf of bread, in addition to the fact that their manufacturing process is rather similar to the baking of bread as well. Foam is formed by a liquid formulation of the material that, through the manufacturing process, grows and expands to its ultimate form, much like dough rises in the oven.
The exterior “crust” on a foam bun is formed as expansion reaches the confines of the machinery that limits the size of the material. This results in a thin, dense film that often feels plastic-like or rubbery, depending on the formulation of the foam. It serves a purpose however, as that extra durability makes it easier to transport the material without damage, and in some cases, foam skins are desired for that durability, for applications like camping pads and the like.
A typical foam bun runs approximately 78” x 82” x 40”. For a five pound density open-cell material, the bun would easily weigh over 700 pounds! The next time you snuggle up with a foam pillow or sit on your couch, remember that this is just a small piece of a much larger whole.