Preface: Here's what I'm doing, how I'm doing it and what the final chamber looks like.
On Friday, I finally performed pressure tests on my Kodak Playsport camera. Using a brilliant idea contributed by Tim Eisele, I connected my pressure chamber to a tire on my MGB. This avoided the risks associated with charging the chamber with a air pump at a gas station where it might explode from overpressurization.
I decided to test the camera as is, with no silicone protection over its ports. The camera is rated to 10', but I wondered if it could handle more. I turned the camera on, started it filming and then sealed it up in the chamber and pressurized it.
The pressure chamber leaked, so the pressure was not constant. I left it alone for 38 minutes and during that time the tire pressure declined from 35 PSI to 15 PSI. That would be roughly equivalent to submersing it to 81' and slowly rising to 35', using 0.43 PSI per foot as an estimate. This is way beyond what we want to do with the camera. For one thing, I'm only rated to 60' and for another, we feel we can get good footage in the kelp beds at about 30-40'.
The camera did not leak and it kept filming the whole time. However, when the pressure was released, the camera turned itself off. I'm not quite sure why this happened, but I suspect the power button thought it was being pressed and when the chamber suddenly depressurized when I disconnected it at the end, it felt like the button had been released.
The camera surpassed all expectations without any modifications. With a good dose of silicone over all inlets, I think it's ready to hit the water for real. Thanks again to Tim and all the rest of you who helped me work through this idea. I hope to share some cool La Jolla kelp bed videos with you real soon.
Update: Tomorrow morning, I'm going to hop on Kodak's support chat and share this with a company rep. I can't wait to hear what they have to say!