Liquid rubber can be used for coatings on various materials and is also an excellent caulking material. It is also used to create molds for medical devices and flexible parts for machinery, among other uses. Liquid rubber is safe to use and does not react with water, oxygen or ozone, and can be poured or brushed into place. It is not flammable and can be used on almost any surface including wood, concrete and metal.
There are two types of liquid rubber products – a soft product that is primarily used as an insulator and a hard product that can be used for waterproofing. The type of rubber required depends on the specific application, for example, a soft rubber is recommended to keep a deck cool underfoot while a hard waterproof product is best suited for metal roofs or for sealing leaky basements and foundations. The best choice is to read the label of any product before purchasing and ensure that it is compatible with the intended application.
The most common liquid rubber is based on an isoprene formula that contains sulfur. When added to the proper mixture and temperature, a chemical reaction known as cross-linking takes place. This process bonds the individual strands of isoprene together and makes them stronger than they would be in their natural state. This is why vulcanized rubber has such high tensile strength and resistance to degradation.
Vulcanization is a 19th century invention, but evidence of rubber that has been cured in other ways goes back far earlier. In what is now Mexico, ancient Mesoamericans ranging from the Olmecs to the Aztecs extracted latex from a plant called Castilla elastica and cured it by adding juice from a local vine. They then made rubber erasers and other products.
Modern vulcanized liquid rubber compounds are typically made from crude or recycled rubber and mixed with activators, accelerators and retarders to control the chemistry of the cure. These chemicals help to speed up the vulcanization process and to improve the mechanical properties of the resulting cured rubber. Other additives may include zinc oxide, carbon black, stearic acid and other extenders, amines and phenolics (coagulants) and anti-oxidants to retard degradation by heat, oxygen and ozone.
To use a vulcanized liquid rubber, first measure the area that needs to be coated and figure out how much liquid rubber is needed to fill it. Then add 10 percent to that number for a small safety margin. Pour component “A” and component “B” into separate cups at the ratio listed on the manufacturer’s instructions, and mix for three minutes until any color streaking disappears from the materials.
Once the rubber is mixed, it has a limited pot-life that determines how long it can be poured or brushed into place before it begins to cure. For this reason, measuring the volume of the area and the size of the model or object being modeled is important before beginning. The simplest method is to calculate the area by measuring the length, width and height of the box or item to be molded and multiplying the measurement of each dimension by its volume.