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Question on cell core

Posted: Thu Jan 18, 2007 9:11 pm
by Cao314159
I just bought the parts to my 2nd and 3rd cannons, made a twin set. They are already assembled, so this post might not do me any good. I bought the PVC for the chamber at a specialty plumbing store, and they said they had no solid core PVC. The salesperson assured me that many people have used this same type of pipe (3 inch sch 40 cell core) and not had any troubles. Me and my friend remotely filled the two cannons and put durable blankets around them, stood at a distance, and they went to 125 with no trouble. Now we are not going to use them past 90 ever anyway, but we wanted to go overkill to test.

My question is, even though it worked for 5 consecutive tests, is the cell core in danger of fracturing after repeated pressuring? Is there anything to wrap the pipe in that will help aid the containment of PVC shrapnel?

These cannons are going to be used to fire confetti, so not alot of pressure will be used, and the units will be housed in thick cardboard tubes. Whay do you think the risk/reward factor is for this?

Thanks in advance.

Posted: Thu Jan 18, 2007 9:29 pm
by chaos
ok first of all im new here so yer and second of all i don't use pvc at all but it sounds like its dangerous i wouldn't use to much pressure and as for reenforcement i have not found much but i might suggest a clear non corrosive lacquer on both outer and inner surfaces of the chamber
soz this isnt much help

Case G :twisted:

Posted: Thu Jan 18, 2007 9:42 pm
by Cao314159
Does anyone know if either kevlar tape or carbon fiber on top of the pvc would help against shrapnel? I am sure a sheet of lead fabric wound around the chamber would contain any explosion.

Posted: Thu Jan 18, 2007 9:51 pm
by judgment_arms
For a good test leave the pressure in it until it bursts or 24hours which ever comes first. That way you know how safe it is, if it doesn’t blow, then it’s safe. If it blows sell tickets to the show! Then with the money you make buy nsf-pw parts from McMaster!

Posted: Thu Jan 18, 2007 10:06 pm
by benstern
CELL CORE + PRESSURE = DEATH!!!!

HOW MANY TIMES DO I NEED TO TELL PEOPLE THIS!!!!!
geeze why do people risk safety and their lives for only a few bucks savings?

I surfed the entire internet so i should know what i am talking about...see my sig?

Posted: Thu Jan 18, 2007 10:21 pm
by Cao314159
I know fully well the dangers of cell core as I have been a lurker here for a while, but I have no where to buy solid core here. I could have ordered, but I needed to meet a sudden deadline for a theater production. I am not asking if it is safe I am wondering if there is anything to make it more safe.

Plus, I think there are more than 97 million web pages in cyberspace :P

Posted: Thu Jan 18, 2007 10:22 pm
by sjog
Get that checked Benstern!

Posted: Thu Jan 18, 2007 10:57 pm
by frankrede
It should be fine as long as you stay under 50 psi and don't leave it pressurized for a long time. No more than 45 seconds. But you should invest into some solid wall sch-40 nsf-pw. You can get it off of mcmaster.com

Posted: Thu Jan 18, 2007 11:03 pm
by judgment_arms
Just so people don’t think I’m retarded, I was joking…

Posted: Fri Jan 19, 2007 6:38 am
by mark.f
benstern wrote: I surfed the entire internet so i should know what i am talking about...see my sig?
ROFLMAO!

If you can't get solid-walled pipe, use threaded steel pipe nipples. 2" chamber of a sufficient length will be fine. What size barrel were you planning to use?

Posted: Sat Jan 20, 2007 1:50 pm
by Cao314159
Well, I would like to have it be under 18 inches long.

By the way, I found a dealer near me that sells 3 inch, sch 80 CPVC. Is that acceptable?