SpudFiles

I made my first combustion cannon and the chamber is 4" in diameter and 2 feet long made from ABS piping. I am going to add the propane metering to it. What would you think the ideal PSI would be for it? I don't want the chamber to explode when I fire.

There's a button on the top right corner of the page that says Wiki. Click that and navigate yourself over to propane metered combustions.
There is no set pressure for a propane meter; you need to calculate (or measure) your chamber volume, meter volume, and meter pressure to achieve the proper propane/air mixture in your combustion chamber.

I would not use propane on a cannon made out of ABS...

AngryChauncey wrote:I would not use propane on a cannon made out of ABS...

After thoroughly testing the durability and impact resistance in my ABS test cannon, I would trust sched 40 cellular core ABS over brittle PVC. The down side in a combustion is it is softer so caps tend to blow off. They may split a seam, but they never shatter sending shards. I've had a couple PVC cannons fail since I built the cannon below which still works.

Generally pressure rated PVC does well in propane combustion cannons. - if they are not cold, hot or have been dropped. ABS is more forgiving on these cannon abuses.

My present line of cannons is using steel chambers and either PVC or ABS barrels depending on the size needed. 2, 3, & 4 are ABS. GB, TB, etc barrels are PVC.

http://www.spudfiles.com/forums/abs-cel ... 17968.html

I just wouldn't feel comfortable with it.

AngryChauncey wrote:I just wouldn't feel comfortable with it.

But you're totally comfortable with PVC?

I hope you'll excuse me while I sit over here in the corner laughing me arse off.

Did I ever say I was comfortable with using propane at all??? I don't recall. Don't think your some sort of genius picking apart people's posts and and throwing it back in their face to make it look like you know what you're doing. Even though you are a mechanical engineer and really do know what you are doing, it's still really obnoxious.[/i]

AngryChauncey wrote:Did I ever say I was comfortable with using propane at all???

A fair point, but I would argue that when you say "I wouldn't use propane with ABS" there's an implication that you WOULD use it with PVC given that PVC is the most commonly used material around here. Was it an assumption? Absolutely. Mea culpa.

As for me being annoying in general? I don't even deny it.

Te habla espanol?

AngryChauncey wrote:Even though you are a mechanical engineer and really do know what you are doing, it's still really obnoxious.

You're not being fair, Mr Hall is a respected member of this forum and is paid to do a job most members here would be glad to do for free, so he really does know what he's doing and should not be dismissed, even if tact might not be his strongest suit en español ó qualquier otra idioma que prefieres