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Cellular core

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Cellular core

Unread postAuthor: redalpha11 » Mon Aug 04, 2008 10:40 pm

i have a cellular core chamber that is 3 inch in diam. an i am just wondering if i have to worry about it blowing me to space and back or not. the dude at ace said it would work i just wont every ones options for this one.
<a href="http://img197.imagevenue.com/img.php?loc=loc503&image=01874_DSC02216_122_503lo.JPG"><img src="http://img197.imagevenue.com/loc503/th_01874_DSC02216_122_503lo.JPG" border="0"></a>
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Unread postAuthor: jon_89 » Mon Aug 04, 2008 10:50 pm

Everybody will probably say dont use it but I am using 3 inch cell core also and it has yet to blow up. I am using tight fitting limes and propane.
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Unread postAuthor: redalpha11 » Mon Aug 04, 2008 10:55 pm

i was just a little worried couse i heard it will killl you with fragments.
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Unread postAuthor: brogdenlaxmiddie » Mon Aug 04, 2008 10:56 pm

I wouldn't worry about the cellular core stuff blowing up with use in a combustion. However, you mounted the ignitor in the side of the cannon.... not good. Try and place those kinds of things on places where its double thick... like where fittings are.
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Unread postAuthor: starman » Mon Aug 04, 2008 11:11 pm

I would retire this thing immediately.... or at least replace the chamber with non-cell core PVC. DWV connecting parts are one thing on a combustion, cell core pipe quite another proposition.

Bury it.
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Last edited by starman on Mon Aug 04, 2008 11:23 pm, edited 1 time in total.
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Unread postAuthor: hi » Mon Aug 04, 2008 11:13 pm

i wouldnt worry about it. every combustion i have made is made of cell core (abs) and im still here. i've made combustions out of cardboard tubes. if you are really worried about it you can wrap it in wire mesh and duct tape.
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Unread postAuthor: frankrede » Mon Aug 04, 2008 11:57 pm

hi wrote:i wouldnt worry about it. every combustion i have made is made of cell core (abs) and im still here. i've made combustions out of cardboard tubes. if you are really worried about it you can wrap it in wire mesh and duct tape.
I would trust cellcore abs over cellcore pvc anyday
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Unread postAuthor: starman » Tue Aug 05, 2008 12:03 am

I'm referring to cell core PVC ..bad.. is what red's got. I don't have any hands-on with cell core ABS...
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Unread postAuthor: brogdenlaxmiddie » Tue Aug 05, 2008 6:54 am

Ok- So, Red- Next time- don't mount the sparker on the pipe... mount it like I said before, and don't use anything in that gun more than hairspray....
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Unread postAuthor: daberno123 » Tue Aug 05, 2008 8:59 am

I'd say replace the chamber. It's not a big deal and it'll only cost you a few bucks.
I'm not saying it will blow up the next time you shoot it, but do you really want to take that chance?
Also by drilling a hole in the pipe you've made it a lot weaker. If it fails, thats probably where it will fail, which is right next to your hand. :shock:
Next time mount the igniter through a double layer of pvc.
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Unread postAuthor: redalpha11 » Tue Aug 05, 2008 11:13 am

alright so i should bury it and never let it see the light again

oh and also this is kinda my idea for a new cannon

i want to sleve it to be on the safe side. thank you for your help every body
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Unread postAuthor: frankrede » Tue Aug 05, 2008 4:56 pm

You don't need sch-80
sch-40 will work fine, just make sure its pressure rated
and your only other problem is how you are mounting you igniter.
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ouch

Unread postAuthor: leehos2 » Tue Aug 05, 2008 5:42 pm

PVC Cellular core turns to shrapnel at320 psi, about the range of a propane blast :wink:
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Re: ouch

Unread postAuthor: brogdenlaxmiddie » Tue Aug 05, 2008 5:47 pm

leehos2 wrote:PVC Cellular core turns to shrapnel at320 psi, about the range of a propane blast :wink:


I disagree. Please check your facts. I was thinking around maybe 120-150 psi. Not 320?

Edit- sorry, didn't make myself clear. I was talking about the pressures caused by a propane ignition. I do not disagree however that cellular core would shrapnel at 320... Just propane doesn't get there.
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Unread postAuthor: jimmy101 » Tue Aug 05, 2008 6:17 pm

Cellcore is fine for any combustion gun fueled with propane (or butane) plus air at atmospheric pressure (no hybrids!). The peak pressure in a closed chamber is ~120 PSIG. In practice, firing spuds, the peak pressure is perhaps 60 PSIG or less.

Below is an easy (an cheap) method of mounting the piezo in a reasonably comfortable handle. For the spark screws I prefer fine thread drywall screws.
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