sealant is a material that seals the tube end of electric heaters, preventing air from entering the tubes and providing seal insulation. The structure of electric heaters is filled with magnesium oxide powder as an insulating layer and heat-conducting medium between the resistance wires and the heat-conducting metal tubes . The strong moisture absorption of magnesium oxide powder can make the electrical resistance properties drop quickly, resulting in a short circuit or electric shock. Hence it is unsafe unless the ends of the electric heating elements are sealed to prevent the entry of moisture and dust. Common sealing materials include silicone rubber , epoxy resin adhesive, glass, silicone oil, etc.
|RTV silicone rubber||Generally used for air dry heating elements which is low load, adopting silicone treated low-temperature mgo powder or medium temperature mgo powder .||Inexpensive and easy to dry; not easy to absorb moisture, and tube end can withstand approx. 200 °C for a long time.||It does not age easily at high temperatures, sealing rigidity is not very strong, the insulation is getting down over time.|
|epoxy Resin（AB)||Generally used for water heating elements with high load (adopts high-temperature mgo powder process)||High adhesion, strong sealing, not easy to age, and tube end can withstand 180 ° C for a long time.||It needs to be dry at high temperatures; the surface easily absorbs moisture (usually requires 2 times of RTV glue seals)|
|glass ceramic||Generally used for dry heating elements with high loads (adopts high-temperature mgo powder processes) or dry heating elements with high temperatures at the tube ends.||Not easy to age, good resistant to acids and alkalis, weatherproof and good insulation and tube end can withstand approx. 420 °C for a long period.||Expensive, easy to break or crack when getting strik, and needs to seal under high-temperature heating|