## Source for sturdy tubes + clear stuffs

I'm going to be dropping a submersible (on a rope for now, no motors yet...) about 600 meters into open ocean. This 'Sub' will need a clear viewing window for a camera, and be sturdy enough to withstand about 700 PSI, according to WikiAnswers (apparently, one vertical meter- 1.09 PSI, right? I'm missing something, aren't I.) So, how thick/ what type of tube will I need, and where can I get it? The project is secret for now, don't ask why I'm doing it.

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Kiteman says: Aug 20, 2009. 4:44 AM
You're starting at 600m???

That's nearly 2000 feet, and you're looking at a pressure of nearly 900PSI.

I don't know a source for your materials, but I do know that you should start much, much shallower than that, increase your depths incrementally until you find your sub's maximum depth - if you drop it to 600m, and then pull up a wrecked mess, you don't know it it failed at 599m or 5m.
Rotten194 (author) says: Aug 22, 2009. 4:34 PM
Yeah, I was going to do that, but I was hoping that someone would know a material that could hold up to those pressures. Then I could simply test that material, instead of say, 5 or 10.
The Ideanator says: Aug 23, 2009. 9:06 PM
Well, if you test each material by itself, it wont be very conclusive, you would need to test the whole thing(maybe skimp on the camera until youve got a working design)
Rotten194 (author) says: Aug 26, 2009. 3:23 PM
My hope is to not need to fill it with anything (Mineral oil is \$60 a gallon O.O), or to fill it with something cheap, but having an empty tube would be better for the camera by far.
The Ideanator says: Aug 20, 2009. 7:37 PM
I'm just guessing here, don't listen to me unless some knowledgeable people can verify it. Polycarbonate type materials are used in bullet-proof glass. I'd also say If you're not going to put a living thing in it, fill it with an inert oil, as oils are unable to "compress" If you want to be ambitious, here are two words for you, pressure equalization. I hope some of this helps you! Also, when you decide whatever you're working on is secret no longer, might you share it with the community?
Rotten194 (author) says: Aug 22, 2009. 4:39 PM
The oil is a great idea, thanks! I think mineral oil is inert as well, good for the camera...
westfw says: Aug 20, 2009. 5:55 PM
700 to 900psi is about the pressure you see inside a CO2 tank, so figure as a rough guess you'll be looking at something about as "sturdy" as a CO2 fire extinguisher (de-certified extinguisher might even be a good starting point.) Any window is going to be "quite thick." You can think about some sort of scheme to internally pressurize (with gas) to match the external pressure. Be careful, though; things with a couple hundred PSI inside make for nice explosions!
Rotten194 (author) says: Aug 22, 2009. 4:37 PM
The internal pressure is a good idea, thanks! I don't want to pressurize it to much though, because I wanted to add a camera inside (whats a submarine without pictures?), and I have a slight idea that sticking a digital camera into an atmosphere of 400 or so PSI isn't a good idea :P.