Silicone Heaters

Silicone heaters are thin, flexible, and lightweight. They can operate between -70°F and 450°F (up to 392°F CSA certified). A fiberglass grid reinforces the silicone layers making silicone heaters rugged and dimensionally stable. The heating circuits inside these heaters are designed to have uniform distribution and because of their proximity to the heated surface, they transfer heat in a rapid, uniform and efficient manner. Silicone heaters are moisture and chemical resistant and can be bonded to flat or curved surfaces. They can be built with many features such as: thermostats, temperature sensors or thermal fuses. Silicone heaters are not suitable for vacuum, radiation, and continuous exposure to oils. Silicone heaters can be manufactured with two types of heating circuits; wire-wound style and etched-foil style. Each construction has its unique characteristics and should be selected accordingly. Wire-wound circuits are formed by creating a specific pattern with resistance wire (single or multi-strand) which is wound around a high temp core for strength and flexibility. The etched-foil circuit is produced by chemically etching a resistive circuit out of a nickel based alloy resistance foil (0.0005in-0.004in thick) in a clean room process similar to the production of printed circuit boards. Etched-foil circuits are more suitable for complex heat distribution patterns and because of the larger surface area coverage of their resistive elements (75% of the surface), these circuits can have higher watt-densities compared to wire-wound circuits.

Specifications
	Wire-wound	Etched-foil
Max Length*	144"	22"
Max Width*	37"	10"
Thickness	0.06" / 0.12"	0.03" / 0.06"
Max Operating Temperature	450°F Intermittent 392°F Continuous
Max Voltage	600 VAC 125 VDC
Resistance Tolerance	-5 / +10 %
Wattage Tolerance	-10 / +5 %
Dimensional Tolerance	Up to 6" +/-0.030 6"-12" +/-0.060 12"-36" +/-0.120 Over 36" +/-1

*Please consult the factory for possible length and width combinations or for longer or wider dimensions

Typical Heating Applications:

Photo processing equipment
Freeze protection
Computer equipment
Medical equipment
Condensation prevention for instruments & equipment
Curing of plastic laminates
Semiconductor processing equipment

Silicone rubber heater detail

Silicone Heaters	Wire-wound circuit	Etched-foil circuit
Max Length	144"	22"
Max Width	37"	10"
Thickness	0.06” / 0.12"	0.03” / 0.06"
Max Operating Temperature	450°F Intermittent / 392°F Continuous
Max Voltage	600 VAC / 120 VDC
Watt Density	Up to 10 W/in²*	Up to 30 W/in²*

*Depending on temperature and application.

Attachment methods

RTV adhesives

In the field, a strong bonding to application surfaces could be achieved by using room temperature adhesive pastes. Red coloured RTV 106 and transparent RTV 116 are the two types of adhesives available. Both these RTV materials are adequate for temperatures up to 450°F.

Factory vulcanization

This is the most efficient method to bond a heater to a surface. Using high temperature and pressure, a silicone heater can be vulcanized to a surface. However, bonding through this method can be carried out only in the factory.

Pressure sensitive adhesive

Silicone heaters could be made with a thin layer of high temperature (320°F) adhesive backing. This adhesive, which can easily bond to practically any surface, is supplied with a protective cover, which can be easily removed before applying the heater to any surface. Temperature and watt density restrictions should be maintained when PSA is used. Please consult factory.

Mechanical fasteners

When a silicone heater is wrapped around an application, the ends of the heater can be fastened by attachments used on fabrics. Eyelets with lacing cords, Velcro hook and loop, metallic fasteners with springs, and independent straps are the most commonly used fasteners.

Thermostats, Sensors and Thermal Fuses

Silicone heaters can accommodate process or safety features such as preset or adjustable thermostats which can be mounted on the heater to monitor its temperature or positioned over a cold section to monitor the temperature of the application. Thermostats are wired directly into the heater circuit or can be wired separately (Pilot Duty) when the voltage or wattage of the heater exceeds the thermostat range.

Adjustable Thermostats
100ºF-165ºF	120/240 VAC	1600W Max
70ºF-205ºF	120/240 VAC	1600W Max
75ºF-375ºF	120/240 VAC	1600W Max

Preset Thermostats
(Open-Close)	125 VAC/15A	250 VAC/8A
60º-40ºF	120º-90ºF	200º-170ºF
85º-67ºF	140º-110ºF	250º-220ºF
110º-80ºF	150º-120ºF	300º-270ºF

* For tolerances please consult factory
* For ambient temperature sensing, preset thermostat sensing side is exposed to the air.

Silicone heaters can also accommodate other temperature sensors such as: thermocouples, RTDs and thermistors for use with an external temperature controller. They can also be supplied with non-resettable thermal fuses to protect heaters from reaching predetermined temperatures.

Lead wire styles

Silicone heaters come only with lead wire terminations. Two styles are available:

Teflon or silicon lead wires

These leads are either sandwiched between the silicone layers or exit on top of the heater. A small silicone patch is placed on the point of exit to provide extra protection. This causes the formation of a slight bump at the point where the wires are attached. To eliminate this problem, the attachment between the internal resistance wire and the lead wire could be made at an external no-heat silicone tab.

Power cables

When silicone rubber heaters are used independently in an industrial application, they can be made with power cables that exit from a silicone transition box attached to the heater. Proper electrical plugs are available with the power cables.