ernie1 wrote:
So if all silicones are not the same, what is the difference in all the "100% Silicone" products on the market? Do some have impurities or are some of the silicone materials different from others and have different properties? Other than price and claims by the manufacturers, how do you know?
silcones can be made to cure in multiple ways, some give off acetic acid when curing, others cure by other means. And silicone is NOT an element, it is a chemical compound that can have multiple formulations and designed with different adhesive properties, different UV properties and different resistance to chemicals.
Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other elements. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.
"More precisely called polymerized siloxanes or polysiloxanes, silicones are mixed inorganic-organic polymers with the chemical formula R2SiOn, where R is an organic group such as methyl, ethyl, or phenyl. These materials consist of an inorganic silicon-oxygen backbone (?-Si-O-Si-O-Si-O-?) with organic side groups attached to the silicon atoms, which are four-coordinate."
Do NOT confuse silicones with the element silicon. Silicones do contain silicon (Si) but that's about it.
The 100% silicone sealant is just as much 100% silicone as is the silicone grease, silicone dielectric compound, silicone sheet material etc. that is also available.
Often times mfg offer a range of silicone and non silicone sealants/adhesives for the same applications, you can pick and choose what you think will work best for your application.
IMHO there are mfg that over the years have developed a reputation for adhesives for different markets with great success. Look at their offerings compared to what you are looking for. 3M and GE are two such companies, They have a wide variety of silicones with for use in many different applications.
when used for the application they are designed for and applied as directed they can work very well.
conversely, using the wrong formulation for the application or not following application directions can end up as a real mess.
And often times that tube of silicone from the hardware store is not a good choice for outside RV applications.
Likewise a UV cure silicone is not likely a good solution for inside use!
