NeighborJ Posted August 17, 2016 Posted August 17, 2016 I'm not there yet, but I had the opportunity to salvage some 12" by 2" wall hdpe pipe from work. I've also got a bunch of 3"-1/2" wall hdpe pipe which has worked well for my 3" shells. I've never launched any mortars larger than 3" but I've made 6" rocket headers. My thinking is when I am ready for the big mortars, this pipe may work. It is quite heavy and takes two men and a boy to move and requires a chainsaw to cut, so if it is not going to work I'd like to know now so I'm not storing a bunch of useless junk for years.
NeighborJ Posted August 17, 2016 Author Posted August 17, 2016 I don't know exactly it's rated at 250 psi, and is 2" thick wall. It was fire protection line, I had it removed so I could run my underground gas line. I have a pic of the ANSI info.
dagabu Posted August 17, 2016 Posted August 17, 2016 I'll look it up but it should be perfect for a gun!
NeighborJ Posted August 17, 2016 Author Posted August 17, 2016 It's ten feet long is there a standard length for guns that size, or would I use a different tube depending on the type of shell? I noticed that a five gallon bucket fits nicely inside. I guess I can make that determination when the time comes.
dagabu Posted August 17, 2016 Posted August 17, 2016 There are many long guns made for canister shells, ball shells don't need the extra length. I am sure there is a standard but I dont know what it is... Here is a table I found: Minimum Mortar Length Mortar ID (in.) 3 - 15 4 - 20 5 - 24 6 - 28 8 - 34 10 - 40 12 - 46
NeighborJ Posted August 17, 2016 Author Posted August 17, 2016 Thanks Dave at least if I cut it in half I can at least move it. It'll be sitting behind my shed for a while until I feel comfortable using it.
dagabu Posted August 17, 2016 Posted August 17, 2016 2-5' length sounds like a plan because the plug will be a foot at least. Giving you the 4' of usable tube, just about perfect!
Mumbles Posted August 17, 2016 Posted August 17, 2016 I've seen that table on Skylighter as well, but I'm not sure where it came from. I included some links to suppliers of 12" tubes to give you an idea of dimensions used in practice. ~4 feet usable length is about a foot shorter than anyone offers. Fiberglass tubes are approximately that length though. http://catalog.kellfire.com/nonfireworks/40http://www.platteriverfireworks.com/shop/index.cfm#1http://web.archive.org/web/20160406064920/http://rtpyro.com/p/14/display-fireworks-mortar1-
ddewees Posted August 17, 2016 Posted August 17, 2016 5x the ID is a good rule of thumb for mortar length.
NeighborJ Posted August 17, 2016 Author Posted August 17, 2016 I might never make the shell because I wouldn't want to dig the hole to stick it in. I won't cut it yet but it's laying next to my driveway so I'll need to move it soon. So now the cut is at 6', I can't see me needing two of them and I certainly don't want to dig two holes.
ddewees Posted August 17, 2016 Posted August 17, 2016 Rent an auger to drill the hole. http://rental-supply.com/wp-content/uploads/2013/07/dingo_auger_wm.jpg
NeighborJ Posted August 17, 2016 Author Posted August 17, 2016 Haha I was starting to like mumbles suggestion of a milling jar. I could bolt a rim to one end and use my truck to run it. I could probably mill 200 lbs in one 10' jar. Use golfballs as media. I'd only need to make one run a year. Yeah I'm better off saving it for the day I can rent the auger. It'd be cheaper then using a $65k truck as a dedicated milling machine.
Arthur Posted August 18, 2016 Posted August 18, 2016 My technique for the plug is to drill radial holes about bore/2 up from the bottom then counterbore these slightly. Push nails in the holes long enough to get almost to the centre. Gaffer tape over all the nail heads to hold them firmly. (the counterbore needs only be big enough to sink the nail heads) Cover the bottom of the tube with cardboard or plastic sheet, leak proof it with gaffer tape! Pour Polyester resin into the tube from the top add some chop strand glass mat in bits, and finish by pouring hot dry sharp sand in! Hot sands helps it to cure quickly, dry sand is a robust and cheap filler. use the same volume of sand as resin ( paper coffee cups is my choice) If the base of the mortar is flat and true you can stand a mortar on firm ground and stake it in position. I use a battery circular saw for cutting plastic tube. I LIKE HDPE mortars they do survive more abuse than cheap Chinese GRP mortars. I don't like reusing the same mortar in a show. The downside with HDPE utility pipe is that some sizes we want as mortars isn't used by the utility companies.
NeighborJ Posted August 18, 2016 Author Posted August 18, 2016 I got lucky with this pipe it is labeled as 16" pipe but the ID is exactly 12". We didn't realize how thick it was at first but the only thing we could find to cut it was the chainsaw. I don't think my battery saw can cut the 2" wall but my sawzall will, I can clean up the edges inside and out with my router to make it look nice. The plug will work nice with the epoxy,fiber and sand on top. If I don't put it in a hole then mabe I can stack sand bags around it with the guide wires. I don't have plans of using this for a while and I don't have a site large enough that I could even use it. But when the time comes I'll be ready.
CrossOut Posted August 19, 2016 Posted August 19, 2016 (edited) Drill in a bunch of screws in a helical pattern every 2 inches vertically with about 4 helix along the base where the plug will be Before you fill in with your fiber-resin mix! You will want the screws in there too secure the plug into the tube as The hdpe can stretch and deform the bottom plug will shoot out the bottom. You will probably need 7-8" screws for that tube... 2" walls is pretty Damn thick so in sure you will be fine there the ones I've always use are about 1/2". Edited August 19, 2016 by CrossOut
Space33 Posted July 25, 2017 Posted July 25, 2017 There's also auger drill rig that can be mounted as truck parts. You can look it up online or if you're not planning to buy, rent trucks like this 1
NeighborJ Posted July 25, 2017 Author Posted July 25, 2017 It's funny, I've found a local farmer who made an auger from a truck axle and mounted it to the 3 point hitch of his tractor. It is powered directly from the PTO and works well. He uses it for fence posts but if I buy or make the bit he said he'll drill the hole. Necessity is the mother of invention. It can also lead to some good friendships. I still haven't used the gun but the day will come. Jason
Wiley Posted July 25, 2017 Posted July 25, 2017 I would put 1/2" rods clear through the pipe and plug, about 2" on center. A mill jar that big would only be good for single chemicals. Milling black powder on such a large jar would not be advisable.
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