gbopp wrote:
BobsYourUncle wrote:
They should be silicone sealed, not polysulphide.
I have done this myself a few times over the years, but I have a friend who has a glass line with a polysulphude machine so that helps.
Polysulphide is that black goo they seal glass units with.
So, silicone or polysulphide to seal the windows?
In the window industry, polysulphide is the basic, commonly used method for making sealed units. It works fine for most stationary applications. Stationary meaning residential applications where there is no movement and no UV exposure of the outside edge of the unit. You will typically get 20 or more years before failure. But a huge amount of this depends on the guy on the end of the application gun. If he is sloppy and leaves little voids or pinholes, then it will not last as long.
Glass units are sealed while laying horizontally, stacked in a pile on top of each other on a special table with rubber spacer blocks holding each unit apart.
In horizontal applications such as a solarium roof, or in a moving vehicle application, it is recommended to silicone seal the units due to extra stress on the glass.
An RV is subject to a lot of bumping, twisting and different angles of the sun hitting the glass, so a better seal is needed.
Polysulphide in professional usage is applied, in simple terms, as a resin and catalyst or hardener via a gun that mixes the two together to be applied to fill the void from the spacer bar to the 2 pieces of glass. Its chemical composition is a flexible rubbery seal once it sets up. But it must not be exposed to constant movement or UV as it will fail prematurely.
Silicone sealing the glass units is not to be confused with the stuff you squirt out of a tube to trim your bathtub or ruin the outside of an RV with!
In glazing terms, silicone sealing is superior to the poly.
The glass sealed unit glazing silicone is applied in the same manner as the polysulphide, but its chemical composition is different. It is silicone based and offers a much higher tolerance to movement and to UV exposure. It costs more because it is more complex to do.
Hope this makes sense without getting too technical!
I learned all this stuff when I worked at a solarium manufacturing plant that had a glass line. It fascinated me so I made sure to learn how it all worked.
