pyrokid Posted March 18, 2015 Posted March 18, 2015 How do we ensure that the payload of a mine shell makes it to a safe and satisfactory height? I am aware of piston-disk designs and such, but I would like to build some mines with salutes and other small garnitures in them and I am concerned about the efficiency of the lift charge in such situations. Am I worrying about nothing?
Arthur Posted March 18, 2015 Posted March 18, 2015 IMO mines are less suitable for salutes unless you have tested the lift and delay timing carefully. Mines usually produce a column of effects which are better done as pearls or tailed comets, Simply to use salutes may not have the effect you want, salutes and stars might be interesting
Wiley Posted March 18, 2015 Posted March 18, 2015 I think that's what pyrokid is referring to. Some nice charcoal streamers with some surprise salutes thrown in there can be really cool. 1
Maserface Posted March 18, 2015 Posted March 18, 2015 I am a little unclear on what you are asking, do you want to know how to build mines with reports? Or are you asking about how much lift powder to use?
pyrokid Posted March 18, 2015 Author Posted March 18, 2015 I am concerned that not enough energy will be transferred to whichever inserts compose the payload. I have this image in my mind that all the gasses produced by the lift will blow past the heavier inserts. Salutes aren't the main objective anyway. I want to do stuff with small color inserts and crossettes.
Wiley Posted March 18, 2015 Posted March 18, 2015 (edited) Just put them in there with/on top of your stars. If they're primed right, they'll light fine and should go plenty high. Edited March 18, 2015 by Wiley
Arthur Posted March 18, 2015 Posted March 18, 2015 Mines tend to use a LOT of lift, don't think it's like a shell.
braddsn Posted March 19, 2015 Posted March 19, 2015 Pyrokid, it might help if we knew what size mine you are making. I make a lot of 2.5" mines, and I lift mine pretty hot. For example, I will use 20g of lift and 50g of stars. I could back off on the lift, but I like the noise and they work great for me. This much lift fires the stars over 100ft in the air (maybe more, depends on star size, etc). I build my mines with discs so it makes them a little more efficient. Just give it a try and see! Drop some inserts in along with your stars. Prime the fuses, and let er rip! Just make sure the blast area is clear! You won't know until you test em. 1
schroedinger Posted March 19, 2015 Posted March 19, 2015 Inserts that have right proportions compared to the diameter of the mine will be no problem. (The right proportions is more a gut feeling then an actual given ratio, but e.g. 10 x 50 mm insert for a 2" and 20 x 60 mm for a 3" normally pose no problems. The much more important part is the timing. Up to 4" the timing shouldn't be longer then 2 s on your first mines. After that work 'em in. Like mentioned above make sure there is nothing near by. If you got problem with lifting heigh, there are a couple ways to increase them, first is to insert a seperation disk or a piston, 2nd is to increase the lift charge, 3rd is to increase the strenght 8f the mine casing itself, e.g. use virgin kraft instead of recycled, more turns of paper, roll the casing wet.
Carbon796 Posted March 19, 2015 Posted March 19, 2015 (edited) Schroedinger, are you talking about mines or roman candles ? Edited March 20, 2015 by Carbon796
dagabu Posted March 19, 2015 Posted March 19, 2015 How do we ensure that the payload of a mine shell makes it to a safe and satisfactory height? I am aware of piston-disk designs and such, but I would like to build some mines with salutes and other small garnitures in them and I am concerned about the efficiency of the lift charge in such situations. Am I worrying about nothing? One method used is what my kids call "The banana shell" where there are four wraps of #50 kraft wound around a mine disk and glued/pleated in about 1/2" into the disk giving the plunger plenty of room to be glued to the lift disk and plunger disk. Using scissors, pleat the outside paper with four pleats, offset the next layer by an inch and repeat for the other two layers. This gives you a sabot of sorts or a wadding of sorts that peels away once it is ejected from the mortar. The difficulty lies in getting fire to the sabot upon launch. The benefit is extremely high shots and top launching of inserts. There were a few really nicely done ones last year at PGI, at least one of them used this "wadding" style of holder for the inserts, comets with salutes attached are pretty memorable!
webski Posted March 20, 2015 Posted March 20, 2015 dag- Sounds very interesting, and a good effect !I'm having trouble visualizing what exactly the construction looks like,could you post a picture or an illustration perhaps, or a link to something similar so I can figure it out and give it a try ? thanks for sharing, webs
Maserface Posted March 20, 2015 Posted March 20, 2015 There is a table in Hardt that shows two basic ways to construct a mine- For mines with tubular effects, I would definitely use the "piston" type.
dagabu Posted March 20, 2015 Posted March 20, 2015 dag- Sounds very interesting, and a good effect !I'm having trouble visualizing what exactly the construction looks like,could you post a picture or an illustration perhaps, or a link to something similar so I can figure it out and give it a try ? thanks for sharing, webs Sure, my daughter still has a few empty canisters from last years competition, she never got the time to build them, too busy running around having fun! There is a table in Hardt that shows two basic ways to construct a mine- For mines with tubular effects, I would definitely use the "piston" type. +1
webski Posted March 21, 2015 Posted March 21, 2015 Is the Hardt table on mine construction similar to the Skylighter tutorial , if so My question concerns the length of mortar tube for 1.5, 1.75, 2", and3" mines. The article referred to short tubes / long tubes for bag mines and/or piston type mines. how long is a short tube, and what would be considered long?I'm going to cut down a couple of my old tubes for mines and need to have some guidelines of what works for you guys.I think I'll be using some bag mines and some piston types depending on the effect I'm trying to create. just trying to shorten the learning curve a bit a not waste a lot of chemicals, trying to dial it in. Looking forward to getting one good one that I can show my wife!(she'll be so proud... or a least humor me for all the hours I'm devoting to my new hobby) webs
Carbon796 Posted March 21, 2015 Posted March 21, 2015 I would consider a long mortar, for mines, just a standard mortar that has not been cut down. I generally build piston mines, shot from standard length mortars.
dagabu Posted March 23, 2015 Posted March 23, 2015 Is the Hardt table on mine construction similar to the Skylighter tutorial , if so My question concerns the length of mortar tube for 1.5, 1.75, 2", and3" mines. The article referred to short tubes / long tubes for bag mines and/or piston type mines. how long is a short tube, and what would be considered long?I'm going to cut down a couple of my old tubes for mines and need to have some guidelines of what works for you guys.I think I'll be using some bag mines and some piston types depending on the effect I'm trying to create. just trying to shorten the learning curve a bit a not waste a lot of chemicals, trying to dial it in. Looking forward to getting one good one that I can show my wife!(she'll be so proud... or a least humor me for all the hours I'm devoting to my new hobby) webs Making a basic mine is really easy, no need for a piston or fancy construction but the mine will be very low, the piston helps soften the shot out of the mortar and helps direct the stars upward. It is usually comets that have robust pistons, a lot of the Chinese mines I have seen just have a perforated disk above the lift charge and the stars above that. Mines will be as complicated as you make them.
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