8 replies to this topic

[jayden]

Concerning starmines, how much lift do you need for x size tube, and x amount of stars?
Does anyone have a table or rough estimate?
I have made starmines before but I haven't done it in a while because my ball mill broke (its up and running now).
I didn't write anything down.
Looking for information on small (1-2cm) to medium (5cm) size tubes.
I think small (1cm) tubes should contain about 1.5g lift with 3-4 stars and small-med (3.5cm) tubes should contain 5g lift with 20-30 stars. Correct?
Thanks, help would be much appreciated.
Jayden.

[seymour]

Your question is very difficult to answer.

Stars have no standard size. Some are as small as 2mm wide, with some getting much larger, all the way to where they are called comets. Comets are not usually made larger than 150mm across, and the boundary between stars and comets does not exist in any permanent way. Throw in the fact that there is a wide range of density of star compositions... I'm sure you see the problem.

There are some rules for how much lift to use per mass of stars (or other items to be ejected in a mine). Off the top of my mind I seem to remember 1/8th of the stars mass in lift.

However we now come across another problem. The performance of black powder varies hugely. This is not only because some black powder burns much faster than other black powder, but some methods of starmine production utilise techniques that make the black powder much more efficient, so much less is needed.

As a rough estimate, your figures look like they would be fine. Also, with smaller mines like the ones you are talking about, you have more leniency than bigger ones.


By the way, it is unpopular to post beginner questions in new threads. This is for two reasons. Firstly because your questions have probably been answered somewhere else, and if they have not there is almost certainly a thread already substantially similar to the topic that you wish to discuss that there is no reason not to post it in there. You can find the answers to most questions by using the search function in the top right hand corner of the forum.

Secondly, if everyone posted all their questions in new threads when they are starting out (and we know how exiting this hobby can be, and that you cannot wait to find things out) then this forum would fill up with far too many threads, and as you will find out when you start searching, there are already thousands

Try not to get too overwhelmed by the archives, there is lots in there!

Edited by seymour, 19 July 2009 - 08:24 AM.

[jayden]

Thanks for the help, I really appreciate it. I shouldn't have anymore questions for now anyway, but I will try not to post simple beginner questions as a new topic.
I have done a bit of pyrotechnics before, done a few small shows and one descent one (on a farm) but then stopped for about a year because the ball mill broke.
The ball mill is running again and I am going to do a display in about 3 weeks so I just asked some questions before I go and start filling the tubes.

Sorry, but I have one more small question :
I have made black match and I want to use it for the fuse on aerial shells.
However, when I put masking tape over top of the fuse it turns into a quick match so that doesn't work.
In the past I have put hot glue around it, but that is a bit iffy and one of the shells that I made exploded prematurely.
Do you have any ideas as to what I could do? I am thinking maybe spolletes but they won't be too good on smaller aerial shells.
As a last resort I could buy visco from somewhere but I have not looked into that as yet.

Thanks, Jayden.

[seymour]

Thanks for the help, I really appreciate it. I shouldn't have anymore questions for now anyway, but I will try not to post simple beginner questions as a new topic.
I have done a bit of pyrotechnics before, done a few small shows and one descent one (on a farm) but then stopped for about a year because the ball mill broke.
The ball mill is running again and I am going to do a display in about 3 weeks so I just asked some questions before I go and start filling the tubes.

Sorry, but I have one more small question :
I have made black match and I want to use it for the fuse on aerial shells.
However, when I put masking tape over top of the fuse it turns into a quick match so that doesn't work.
In the past I have put hot glue around it, but that is a bit iffy and one of the shells that I made exploded prematurely.
Do you have any ideas as to what I could do? I am thinking maybe spolletes but they won't be too good on smaller aerial shells.
As a last resort I could buy visco from somewhere but I have not looked into that as yet.

Thanks, Jayden.

For the reasons you describe BM is not suitable for timefuse, even if it can be made to work occasionally with the glue.

Why would spolettes not be good in small shells? They should work perfectly.

[jayden]

For the reasons you describe BM is not suitable for timefuse, even if it can be made to work occasionally with the glue.

Why would spolettes not be good in small shells? They should work perfectly.

Is a 6mm spollete fine on the smaller shells (1-1.5 inch)?
I just thought that they might effect the break a bit.
I was going to do spolettes just on the 2 and 3 inch shells, but I will use them on the smaller shells as well then.
Once again, thanks heaps.
Jayden.

[pyrotrev]

Thick (3mm) Visco can also be used as delay fuse for small shells if you can get some (thinner stuff is a pain to use reliably), but as with a spolette, make sure it's well fixed and sealed into the case. Either way any delay fuse needs to have a well compacted powder core to ensure a steady burn rate and that it doesn't burn through.

[sir steve]

Concerning starmines, how much lift do you need for x size tube, and x amount of stars?
Does anyone have a table or rough estimate?
I have made starmines before but I haven't done it in a while because my ball mill broke (its up and running now).
I didn't write anything down.
Looking for information on small (1-2cm) to medium (5cm) size tubes.
I think small (1cm) tubes should contain about 1.5g lift with 3-4 stars and small-med (3.5cm) tubes should contain 5g lift with 20-30 stars. Correct?
Thanks, help would be much appreciated.
Jayden.

I would say half that, depends on the BP.

Steve

[Kurt]

hey jayden aka. pyro buddy
hey check out this site it is pretty good!!
http://www.creagan.net/fireworks/
lots of info!
kurt,

[Mortartube]

As far as your 5cm mines go, I would suggest that you use a lifting plate. A tight fitting cardboard disc perforated a number of times with a bradawl. The stars go on top of the plate. This will help with the performance of your mines.

Weigh the amount of stars you put in the mine and also the amount of lift and write it down, then do some tests to find the optimum.

Small spoolettes should be fine or visco as suggested. If using visco cut it at an acute angle to expose as much of the powder core as possible and prime it.