Arthur Posted November 29, 2009 Posted November 29, 2009 I've been trying some mines made in the tube. I have some 45mm tubes to play with! Does anyone care to share any clues for optimising the performance. I had 20g of coarse lift powder with a perforated disc above then a thin bag containing 60g of 10mm stars. Ignition by QM with a visco time delay. The noise was too loud and the lift was too low some of the stars came back down too far. Is a top disc a good idea? Do mines do well with a faster lift than shells, I could sieve something finer out? Has anyine any clues as to scaling up? I'd like to try some 3" as well but these may be made to reload.
new2pyro Posted November 29, 2009 Posted November 29, 2009 (edited) I've been trying some mines made in the tube. I have some 45mm tubes to play with! Does anyone care to share any clues for optimising the performance. I had 20g of coarse lift powder with a perforated disc above then a thin bag containing 60g of 10mm stars. Ignition by QM with a visco time delay. The noise was too loud and the lift was too low some of the stars came back down too far. Is a top disc a good idea? Do mines do well with a faster lift than shells, I could sieve something finer out? Has anyine any clues as to scaling up? I'd like to try some 3" as well but these may be made to reload. from what i've seen you can use half that lift charge. push a paper towel plug down on top of the stars tight but don't crush the stars. that will let some pressure build. 6-10 grams of lift should be enough. you can search for star mine tutorials. look on skylighter .com and pyroguide.com. pyrobin.com has lots of pics and vids. check it out. Edited November 29, 2009 by new2pyro
Mumbles Posted November 29, 2009 Posted November 29, 2009 I would definitely go with finer lift. A 2FA(-4+12) powder has proven to not pack enough punch for 3" and smaller mines for me. These are all of the bag/reloadable type. I've taken to using a 4FA powder (-12+20). I use 1/10th the weight of stars/inserts for the lift. It seems to get them up pretty well. I use a sabot type of deal inside the mine. Two perforated disks with a wad of newspaper in between them. It's been a while since I made any single fire mines. For the single shots I did as new2pyro suggested, and placed a plug of something above the stars. Paper towels or toilet paper. I also had a plug of something above the lift, as the tubes were side fused. The paper towels/toilet paper brought with it some flaming debris, which I would not be comfortable with currently. If I were to do it again, I would make some chipboard plugs like the following for the top plug, and just a thin perforated disk for above the lift. http://www.cannonfuse.com/store/pc/catalog/caps-endplugs.jpg While we are on this subject, I have a question for anyone with experience. Have you noticed any difference between putting the lift into a bag, verses loose at the bottom of the mine? With shells I have noticed a sharper lift with my ball shells verses canisters despite using the same powder. The only real difference is that the ball shell lift is placed into a plastic bag, and taped with aluminum tape to the bottom of the shell. It's somewhat compressed to a solid lump. The canister shells have a tight knot at the bottom of the shell, and the lift is dumped in loose to the outer paper wrap. It's twisted and tied off. It is is noticeably loose.
usatrapper Posted November 29, 2009 Posted November 29, 2009 I like to put little holes in my discs to allow fire to pass through.
firetech Posted November 29, 2009 Posted November 29, 2009 A piston on top of the lift with holes in it makes a huge difference it the height of the stars.
Miech Posted November 30, 2009 Posted November 30, 2009 @Mumbles: I think it is rather the shape and weight of the projectile causing the difference in sound. At least my ball shells always have a somewhat sharper sound than my cannisters. Probably the weight is of importance as well, cannisters usually are heavier and thus have a different velocity and pressure under their butts. There is one exception so far, that was my parachute shell. But hell, I lifted it with 1/5th to be absolutely sure it would go very high.
usatrapper Posted December 6, 2009 Posted December 6, 2009 I like to put little holes in my discs to allow fire to pass through. Yes but they will all ignite.
andyboy Posted December 6, 2009 Posted December 6, 2009 To get the best performance I always put the lift and the stars in a paper bag sort of deal (made out of several layers of paper), insert a fuse at the top and tie it with a few windings of strong string. No need for discs, plugs or anything else.
Mumbles Posted December 6, 2009 Posted December 6, 2009 Have you tried side by side comparisons with disks or sabots? In my experience there is a definite performance increase between nothing, a disk, and a sabot. The stars shoot higher, and stay in a tighter pattern with some sort of barrier/lift disk in there.
patsroom Posted December 7, 2009 Posted December 7, 2009 There is an article MAKING FIREWORKS MINES By Ned Gorski in Skylighter Fireworks TipsOctober 2nd, 2008 -- Issue #114 that just might be of interest I hope you take a look. As it was about a way to lift mines. I hope this helps
Ventsi Posted December 7, 2009 Posted December 7, 2009 Have you noticed any difference between putting the lift into a bag, verses loose at the bottom of the mine? I personally have, the way I do it though is using cling wrap, and wrapping the QM/BP using one layer. I don't know if this contributes to lifting the stars higher[i assume it does.] but it definitely has a much sharper lift sound and a harsher take off for the stars. But when making more than one mine its easier to do, and makes sure your BP doesn't migrate to small crack or go up between the stars. I always use a piston ala Night Hawk style, simply a circular piece of cardboard[cereal boxes etc.] with a fixed number of 3/16" holes into it , this is the most crucial part IMHO, as well as wrapping the while thing in some kraft when you're done.
andyboy Posted December 8, 2009 Posted December 8, 2009 Have you tried side by side comparisons with disks or sabots? In my experience there is a definite performance increase between nothing, a disk, and a sabot. The stars shoot higher, and stay in a tighter pattern with some sort of barrier/lift disk in there. I have tried with disks, sabots and even making "shells" with a break-away top. The best result came from the break-away top but since I'm always looking to simplify things I started using paper-bags. Sabots and disks are on the other hand necessary IMO when having inserts in the mines such as buzz-crackers and so on. To clarify the break-away top thing. I just made italian shells but made them with less pasting on one end so that end would blow first. Off course, that end was placed up. I never separate the BP from the stars, that's up to gravity to deal with, I just shake them a bit before use so the BP settles.
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