Bonding stainless steel to glass...

[treedog]

We are building some small 316/316L stainless steel enclosures that will house underwater cameras. They will have 38mm diameter round openings where a 42mm diameter disc of borosilicate glass lens will be bonded from the backside directly to the 316 stainless housing. The borosilicate glass lens will be flat as will the stainless steel. The housings will be submerged in ocean water to about 3-4 feet depth for extended periods of time so they need to be water tight. Which of your adhesives will work best for our application?

 

[Compositepro]

RTV silicone would work, but a better design would be an O-ring seal with a bolted clamp ring.

 

[MintJulep]

Just a 2mm overlap? I think it will be difficult to get a consistent seal with any adhesive.

The best thing to do would be to fuse the glass directly to the metal.

The next best thing would be to buy a pre-made fused glass window with a bolted o-ring flange and install that.

 

[olmanpete]

Given your size constraints I would use a glass frit sealant formulated for stainless steel. These fire at about 600C. Owens Illinois makes several that bond by forming a new oxide between the glass and metal. This is green and opaque, but will be restricted to the region of the seal. You will need to do some development work since binders etc. affect the seal. I have used this on borosilicate glass and it is VERY strong.