What Is Gunite?
Anyone that works with Gunite must accept one simple fact; few days will pass without hearing the phrase, “What is Gunite?”. In many cases the person that asks the question is more puzzled after hearing the answer. It’s so unique and different that it’s difficult to give a short and clear explanation.
In the early 1900’s, Carl Akeley, a famous hunter and naturalist of his day who practiced taxidermy, came up with a method of spraying plaster onto animal shaped wire frames. He placed a dry plaster mix into a chamber, that resembled a pressure cooker, and used compressed air to push the powder thru a hose to a nozzle where mixing water was added. The results were outstanding. He found that the product, later trade named Gunite, was extremely workable. The material didn’t slump off the wire frames like it did when it was premixed and troweled on. Also, it didn’t set up as fast which allowed finer details to be sculpted into the figures. Gunite was originally developed for the art of taxidermy.
Later, in 1910, a double chamber “cement gun” was developed based on Akeley’s design. It was introduced to the construction industry as a method to patch deteriorated concrete. Instead of plaster, a cement and sand mortar was used. The results were outstanding and in 1911, Patents were granted for the “Cement Gun” which is what the apparatus was called and for “Gunite” the material produced by the process.
In 1915, and Allentown, Pennsylvania business man named S.W. Traylor recognized the market for the new invention. He bought the rights and formed the Cement Gun Company of Allentown, PA, to both build the machines and do the Gunite construction work.
As time passed the many uses of Gunite came to light. It was ideal for creating thin but strong concrete linings and coatings. It was easy to create curves and special shapes in concrete. Bridges, dams, reservoirs, pools, tanks, canals, docks, slopes, tunnels, pipelines and the like all became candidates for Gunite. Further, steel producers, experimented with patching firebrick using Gunite with remarkable results. The patches were easy to install and long lasting. Eventually, firebrick linings became obsolete replaced with Gunite concrete which was less expensive, quicker to install and lasted longer.
In the 1930’s, the term “Shotcrete” was coined by the American Railway Engineering Association to describe the process to produce the trade named “Gunite”. Later, in 1951, The American Concrete Institute adopted the term shotcrete to describe the “dry mix” process known as Guniting. The term shotcrete is now also used to describe the “wet mix” process that was developed during the 1950’s as an alternative to Gunite.
Gunite is then the trademarked term for the material produced by the “dry mix” shotcrete process. And there are two types of shotcrete, “wet mix” and “dry mix” as defined by the American Concrete Institute.
Despite the advances in materials used for Gunite, the process remains unchanged to this day. It is generally accepted that the quality of Gunite depends solely on the experience and skill of the artist. Unfortunately, we routinely run into people who have had a bad experience with Gunite, most always traceable to lack of skill.
Gunite remained a proprietary trademark until 1971 when it became part of the English language. Look in the dictionary and you’ll likely find the word sandwiched between gung-ho and gunk, an appropriate location. Webster’s defines Gunite in the following way; Gun·ite \ trademark used for a mixture of cement, sand and water sprayed onto a metal mold.
Just as accurate is to describe Gunite as somewhere between gung-ho and gunk, in more ways than one!
Kraemer Gunite, Inc.
PO Box 305
Pitman, New Jersey 08071
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