Hi again guys...

I am doing a project in which I am making a waterproof 316/316L stainless steel enclosure to install a small closed circuit camera which will be submerged under saltwater for extended periods of time. I need to install a glass lens for the camera to "see" through so I was simply going to make say a 40mm hole and then glue a 45mm piece of glass over the hole....but then I thought... there has to be a better way!

I have disassembled some dive watches in the past and the crystals are held in place by what seems to be a PTFE ring and they are simply pressed into place. In fact I have a watch rated to 300M that the crystal is pressed on this way...if you remove the back from the watch and take out the movement you can simply "pop" the watch crystal+ring right out with your thumbs. Then to reinstall you just press it back in with your hand from the front!!! Doesn't get much simpler than that.

Do any of you know how this press in lens setups is designed? If I have a 40mm diameter by 3mm thick flat lens. How large should I make the opening? How thick, tall, and what inside diameter should the PTFE ring be so that I get a nice strong seal? (keeping in mind I plan to use this at a max of 10 feet or so deep under water)

What kind of material is that ring/gasket made of? Is PTFE the best choice? If I wanted to make something that could be submerged for many months or perhaps years at a time what material should I use for the gasket and for the lens?

Any ideas where I could source a gasket like this?

Thank you in advance for any help and/or ideas .

I made a drawing to illustrate the method I am talking about (please excuse my poor drawing skills) Anyway, this is the method I am trying to figure how to implement....



Below is a diving watch that I pulled apart which is using this same system. Many very expensive diving watches rated to 100+ meters use the same. It is a simple "plastic" (I say plastic because it is rigid NOT soft like an o-ring I am not really sure what it is made of). But basically this ring fits snuggly around the glass and then the glass+ring is pushed in to the opening with hand force...NO LEAKS...you can pop it right back out by pushing on the glass from inside the watch with your thumbs...<u>Nothing </u>else is holding/sealing the glass just the "plastic" ring....<br>

I would do it differently ( But then I have a lathe or 2).

Use a O ring behind the lens for sealing. Cut a grove in the cannister in front of where the lens sits and then use either a split ring or O ring to hold the lens in place. I have seen many of lights using this system. The deeper you go the better it seals.

Sorry for the crap image but the red is the lens and the solid black is the O rings

Thanks for the reply Packhorse. The image gets the point across perfectly. So far in my research that setup seems to be the best one. Also, I am having a hard time sourcing a gasket like the one I pictured.

What material would you recommend for very prolonged (several months and/or years) under saltwater for those o-rings?

Thanks again!

Im no O ring expert. Try asking the guys at Seal House in East Tamaki. Thats where I get all mine and the do different materials.

Treedog, SIL http://sealimports.co.nz/ are probably the most comprehensive source of o rings in NZ and they have a searchable online catalogue. PM me your email address and I'll send you a PDF of the Parker oring handbook which will answer any question you may ever have regarding orings.


Hey Packie what keeps the second oring from extruding?

I guess I didnt draw it all that well. The one behind the lens has a lip that keeps it in place. The one in front isnt under all that much pressure so it will not get squeezed out.

If you get a chance have a look at Gurus Dive Rite can he brought off Nem.