Clay Times Back Issues Vol. 21 Issue 99 - Winter/Spring 2015 - Page 29

ALL ABOUT WAX — What You’ll Need to Resist! Wax is a material often used in ceramics as a glaze resist. It can be used to create glaze effects or to keep glaze from getting on the bottom of the piece where it is not wanted. But this material, which is so safe when it is cold, becomes hazardous when melted or burned out in a kiln. A new technical data sheet entitled “All About Wax” will soon be released by Arts, Crafts and Theater Safety. It is a good reference, and even better, it is free. The title of “All About Wax” is not an exaggeration. The document is 17 pages and covers numerous facts about many types of waxes such as paraffin, soy waxes, candle wax, and beeswax. The data sheet illustrates the chemical structures of various waxes, the many ways wax is used in art, and how to use it safely in the studio. Drawings of basic ventilation systems are also included. Heating and Burning Wax The data sheet explains that when heated to complete melting, pure waxes are as clear as water. Just as water evaporates, so too, do small amounts of wax get airborne from melted wax. And like water, the hotter the wax, the faster it evaporates, and the more the wax gets airborne. However, unlike water molecules that simply disperse as a vapor (moisture) in the air, airborne wax molecules condense into tiny particles called “wax fume.” BY MONONA ROSSOL Wax Fume Wax fume, or tiny, invisible, combustible wax particles, can collect above the melted surface of any wax. If the concentration of particles is sufficient, they can burst into flame or explode at the slightest exposure to heat, static electricity, or other ignition sources. When I was a pottery student at the University of Wisconsin in the 1960s, I witnessed this phenomenon. An electric fry pan was turned to a low temperature to melt paraffin for dipping the bottoms of pots as a glaze resist. One day, with no warning, an explosion and fire ball above the pan turned the glaze room into a shambles. Luckily, I was outside the glaze room looking in at the time. Wax fume also can irritate the upper respiratory tract and cause nausea. Gas and Vapor Wax Emissions As the temperature rises above the melting point, some of the wax molecules will begin to change. The heat will enable oxygen to more easily react with the wax and the vapor molecules will begin to break down into smaller chemicals. Some of these breakdown products will be gases. Some will be liquids in the vapor (molecular) form. They can be detected by the “hot wax smell” that becomes more and more noticeable as the temperature rises. One of the most common groups of these chemicals are the aldehydes. The simplest of these is formaldehyde. This chemical is an irritant and carcinogen, and causes allergies. But many other more complex aldehydes are also created. The ones in the EPA study cited above included acetaldehyde and acrolein, which also cause irritation and allergies. Some of these other aldehydes may also be able to cause cancer. Other gas and vapor emissions include straight and branched chain and benzene ring-containing solvents, alcohols, ketones, acids, and more. Hundreds of different chemicals can be expected. These are all toxic in various ways and to varying degrees. Emissions from Burning Once a wisp of smoke or a flame appears, the wax is now burning and the number of emissions increases. At this point, the amount of oxygen incorporated in the process also increases, while the size of the molecules produced decreases. The smallest molecules will be carbon dioxide, carbon monoxide, and water. Hundreds of other molecules and some carbon soot particles will be created. The total of individual chemicals may number in the thousands. None of these is good for you—some will be toxic, and some will cause cancer. In this respect, wax is no different from any other carbon-containing substance. All burning hydrocarbons release toxic and cancer-causing substances. Whether it is wax, oil, continued on next page Studio I Health & Safety CLAYTIMES·COM n WINTER / SPRING 2015 29 BY MONONA ROSSOL W ax is a material often used in ceramics as a glaze resist. It can be used to create glaze effects or to keep glaze from getting on the bottom of the piece where it is not wanted. But this material, which is so safe when it is cold, becomes hazardous when melted or burned out in a kiln. A new technical data sheet entitled “All About Wax” will soon be released by Arts, Crafts and Theater Safety. It is a good reference, and even better, it is free. The title of “All About Wax” is not an exaggeration. The document is 17 pages and covers numerous facts about many types of waxes such as paraffin, soy waxes, candle wax, and beeswax. The data sheet illustrates the chemical structures of various waxes, the many ways wax is used in art, and how to use it safely in the studio. Drawings of basic ventilation systems are also included. Wax Fume Wax fume, or tiny, invisible, combustible wax particles, can collect above the melted surface of any wax. If the concentration of particles is sufficient, they can burst into flame or explode at the slightest exposure to heat, static electricity, or other ignition sources. When I was a pottery student at the University of Wisconsin in the 1960s, I witnessed this phenomenon. An electric fry pan was turned to a low temperature to melt paraffin for dipping the bottoms of pots as a glaze resist. One day, with no warning, an explosion and fire ball above the pan turned the glaze room into a shambles. Luckily, I was outside the glaze room looking in at the time. Wax fume also can irritate the upper respiratory tract and cause nausea. Gas and Vapor Wax Emissions Heating and Burning Wax However, unlike water molecules that simply disperse as a vapor (moisture) in the air, airborne wax molecules condense into tiny particles called “wax fume.” As the temperature rises above the melting point, some of the wax molecules will begin to change. The heat will enable oxygen to more easily react with the wax and the vapor molecules will begin to break down into smaller chemicals. Some of these breakdown products will be gases. Some will be liquids in the vapor (molecular) form. They can be detected by the “hot wax smell” that becomes more and more noticeable as the temperature rises. One of the most common groups of these chemicals are the Other gas and vapor emissions include straight and branched chain and benzene ring-containing solvents, alcohols, ketones, acids, and more. Hundreds of different chemicals can be expected. These are all toxic in various ways and to varying degrees. Emissions from Burning Once a wisp of smoke or a flame appears, the wax is now burning and the number of emissions increases. At this point, the amount of oxygen incorporated in the process also increases, while the size of the molecules produced decreases. The smallest molecules will be carbon dioxide, carbon monoxide, and water. Hundreds of other molecules and some carbon soot particles will be created. The total of individual chemicals may number in the thousands. None of these is good for you—some will be toxic, and some will cause cancer. In this respect, wax is no different from any other carbon-containing substance. All burning hydrocarbons release toxic and cancer-causing substances. Whether it is wax, oil, continued on next page CLAYTIMES·COM n WINTER / SPRING 2015 The data sheet explains that when heated to complete melting, pure waxes are as clear as water. Just as water evaporates, so too, do small amounts of wax get airborne from melted wax. And like water, the hotter the wax, the faster it evaporates, and the more the wax gets airborne. aldehydes. The simplest of these is formaldehyde. This chemical is an irritant and carcinogen, and causes allergies. But many other more complex aldehydes are also created. The ones in the EPA study cited above included acetaldehyde and acrolein, which also cause irritation and allergies. Some of these other aldehydes may also be able to cause cancer. Studio I Health & Safety ALL ABOUT WAX — What You’ll Need to Resist! 29