Sigg bottle questions.

[spudtyrrant]

So here is a question. I did some calculations based on burnt latke's propane pipe calculator. It seems that for such a small volume chamber I will only need a 1/4X2.27 inch pipe. Question is,how in the world am I going to be able to fit the pressure gauge and the two valves into that small of a space?

What pressure did you want to have the propane at?
I would use lower pressure so it would be easier for you to make a practical meter.

[Freddy4130]

I just used the stock psi of 90.

[btrettel]

If anyone's interested in a more durable lightweight aluminum gas chamber, check out this thread: http://www.spudfiles.com/forums/light-a ... 20352.html

Draconis at NerfHaven plans to make an order for some tanks with a rated pressure of 240 psi (and a burst pressure of 600 psi). The minimum order is 100 units, so he needs to gauge interest.

[Moonbogg]

If anyone's interested in a more durable lightweight aluminum gas chamber, check out this thread: http://www.spudfiles.com/forums/light-a ... 20352.html

Draconis at NerfHaven plans to make an order for some tanks with a rated pressure of 240 psi (and a burst pressure of 600 psi). The minimum order is 100 units, so he needs to gauge interest.

Why is the burst pressure so close to the rated pressure? This doesn't make any sense for a commercially available unit, at least thats what I think. A safety factor of 2.5?

[btrettel]

I too would prefer a higher safety factor. I don't run it beyond 150 psi and I have a pop-off valve set at 175 psi.

The low safety factor has to do with the fact that these pressure vessels are meant to be temporary (or so I think). More information is available here. These pressure vessels are meant to be (but aren't necessarily*) DOT-39 certified, which means they are generally not heat treated. DOT-39 certified vessels also can't legally be transported in the US after being refilled (I haven't read of that being enforced).

An ideal solution would be a heat treated slightly thicker cylinder. I'm not aware of any company that makes such a product, but if they did and marketed it right I'm certain they'll make a mint.

Here's some more info for those interested: http://www.catalinacylinders.com/lp.html

* The tank I have is NOT DOT-39 certified, but it was still designed to be a DOT-39 certified vessel. There's no legal problem with its transport, and as I mentioned, I use it at lower pressures than the recommended pressure, so it's very safe. The material is more brittle than it could be, but it's still aluminum.