Hot Wax therapy is one of several methods available to the therapist of applying heat directly to the surface of the body. Paraffin Wax supplied by EMS Physio Ltd melts at between 45° and 47° C. The wax is held at a temperature just above its melting point and the part of the body being treated is either immersed in the molten wax or the wax is poured onto it. Heat is transferred from the wax to the treatment area by thermal conduction. Although temperatures above 45° may lead to skin damage under normal circumstances, immersing a hand or foot in paraffin wax at 50° C is quite comfortable. Water or oil at the same temperature would be uncomfortable and possibly damaging. However, when the skin comes into contact with the molten wax, the wax immediately next to the skin solidifies forming a thin insulating layer. This insulating layer, which is of low thermal conductivity, lowers the rate at which heat energy is applied to the skin to a level which is safe.
The latent heat of fusion of the wax is released as the wax solidifies, therefore, applying heat to the treatment area at constant temperature. In normal treatment several layers of wax are applied and further heat is released from the wax into the skin. Another consequence of the solid layer of wax is that moisture is prevented from being lost from the surface being treated. At the end of treatment, when the wax is peeled off, the skin is left moist and soft.
The Varitherm Wax Bath comprises a resin tank which holds the paraffin wax, surrounded by an electrically heated, thermostatically controlled water jacket. The temperature control may be set to maximum in order to provide rapid melting of the solid wax when the unit is first switched on. After almost all of the wax is melted, the temperature control is normally set to approximately 50° C so that the paraffin is just in its molten state. It is advisable to check the actual wax temperature with a suitable thermometer prior to treatment.