bmarley5780 Posted December 30, 2007 Posted December 30, 2007 Heya- I have lots of 3" ID tubes that are suitable for morter tubes... What are good specs for a paper shell (cylinder) of paper.
bmarley5780 Posted December 30, 2007 Author Posted December 30, 2007 Might have found my own answer... Looking on S.L- I see that they have their tubes of 2 1/2" ID1/8" WALL2 3/4" OD
Mumbles Posted December 31, 2007 Posted December 31, 2007 Are you planning to purchase tubes, or roll your own? The way you manufacture is generally different between the two. I'd suggest rolling your own. It's very easy actually. Get a 2.5" former. A variety exist. I personally use a 12oz contact solution bottle. Soda/beer cans are also quite serviceable. Soda cans are 2.55" OD, so the end disks end to have a bit of slack inside, but thats generally not a problem. You will want to roll 3 turns of 70lb paper, which is approximated as paper grocery bags. This is about 24" long. I tend to make my 3" shells a bit longer than they are wide. I don't know why I do this exactly, but it has worked thus far for me, so it stays. I'd suggest using (shell height) + 2.5" I use 1" of over lap on the top, and 1.5" on the bottom. The top is where the fuse will be, and thus needs a little less than half of the end disk overlapped to accomodate this. The bottom gets a little bit over half to get a good seal, and absorb some of the lift force. I can provide more construction details if you'd like. Just ask.
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