What a difference an “e” makes! Silicon is the material of electronics. It’s hard and brittle and makes lousy gaskets. Silicone on the other hand is soft and elastic, which makes it a good choice in many gasket applications. Here’s what makes this polysiloxane material so useful.
Silicon and silicone are closely related. Silicon is a naturally-occurring element while silicone is a polymer that combines silicon atoms with those of oxygen and the H3C hydrocarbon compound. The result is a soft, plastic-like material that springs back after being compressed.
More Silicone Properties
In addition to compressibility, other useful features of silicone include:
- Poor adhesion, so it doesn’t mark surfaces
- Low toxicity, making it useful for food and medical applications
- Resists degradation by ultraviolet light (sunlight)
- Low electrical conductivity
- Repels water
- Ozone resistant
- Retains its flexibility over a temperature range of -94 to +392°F
These properties make silicone gaskets a good choice in a range of food, medical and electrical applications. It won’t taint foods and it handles a wider temperature range than many other gasket materials.
In some regards, silicone performs less well as a gasket material than the alternatives. Some others have higher strength and better compression set recovery for instance. It’s also attacked by hydrocarbons like most oils and fuels, and resistance to acids and alkalines is poor. In short, unless you need the special properties of silicone there may be better alternatives.
Silicone is available in both solid sheet and as a foamed or cellular material. Silicone foam may be either closed or open cell.
Silicone comes in many colors, (which may not be food grade, so check before ordering.) There are also many variants tailored for specific application needs. Some will go to lower temperatures than that given above, while others have been engineered for higher strength or even electrical conductivity.
If you’re considering using silicone gaskets we respectfully suggest speaking with one of our material specialists. There are many instances where silicone is an excellent choice, but sometimes other materials may perform better.