Plastic bongs made with acrylic are clear plastic that resembles glass, a transparency rate of 93% makes acrylic the clearest material known. Very thick glass will have a green tint, while acrylic stays clear. There are two basic types of acrylic: extruded and cell cast. Extruded or continuous cast acrylic is made by a less expensive process, is softer, can scratch easier and may contain impurities. Cell cast acrylic is a higher quality acrylic that is most used in bong production. A unique property of acrylic is its ability to be shaped. There are no seams in acrylic structures, as chemicalwelding at the molecular level melts seams into one piece of solid material. Seams that are welded and polished are invisible. Acrylic is chosen over glass for many reasons, acrylic is many times stronger, making it much more impact resistant and therefore safer, and also insulates better.
There are some misconceptions about acrylic bongs, namely that it yellows, turns brittle and cracks over time. Though this is true of very cheap forms of plastic bongs, it is not so with acrylic.When taken care of, an acrylic bong remains new looking regardless of age or exposure to sun. Some people worry that acrylic scratches too easily, but unlike glass, scratches can be easily buffed out of acrylic. Cleaning of acrylic bongs is also considered easier by some. The occasional knock on the table/sink/etc which is a frequent, if not unavoidable consequence of regular use and cleaning is hardly a concern for acrylic bongs.
People ( especially in amsterdam ) generaly use bongs to smoke what is called today soft drugs which is know as : marijuana /cannabis ! Asian are the ones to thank for the shape of these water pipe ( bongs ).
Using acrylic bongs allow smoke to be inhaled alot more deeply and rapidly. Results is increased efficiency , thus less marijuana is needed. On top of each acrylic bongs you'll find a bowl in which you place your herbs ( marijuana for example ). The smoke passes through the liquid ( usualy water ) before getting to the mouth. Some of carcinogens like tar are filtered . The water in the acrylic bong also cools the smoke.