Attempting My first Star Mine - Questions

[stix]

I've made a 3/4" (19mm) star mine/gun for testing small 1/4" cut stars.

I'll be using my first ever cut stars from this thread:
http://www.amateurpyro.com/forums/topic/9514-kings-glitter-as-i-call-it/

First off, I'm using some spiral wound cardboard tubes that I have. The tubes are 3/4" (19mm) ID with 1/8" wall thickness, 8" long. I've coated the internals with sodium silicate solution and plugged one end with an inch long piece of dowel - this leaves 7" of length. The length is around the 9 x ID which I've read is the standard.

My lift charge will be my homemade paulownia 4FA. It burns reasonably quick and the volume is about 1 level teaspoon per 2.6grams. I know that this is the "how long is a piece of string" scenario but a few pointers would be helpful.

 

I read somewhere to insert a snug fitting disc of thick cardboard down the tube after the charge and stars which helps build pressure, which is exactly what i did. I tested with a 1/4 teaspoon of charge and some inert material to determine how much lift charge is required. Well, a pretty pathetic result. The "mock stars" went up only about 15ft and the cardboard disc didn't even exit the tube!!

 

I've since read that compacting some wads of tissue paper down the tube is the way to go. I'll do one more test using wads of tissue paper and perhaps increase the charge - then do the real one

 

Any thoughts and advice much appreciated.

 

Cheers.

[Col]

Tissue tends to create burning debris. A decent top (pressure building) plug can be made by scrunching up a bit of kraft, stuffing it in a spare tube and compacting it with a solid rammer.When you push it out it`ll expand a tad.

For mines, i use a piston or disc with one or more smallish holes punched in it to let the fire through to ignite the stars, it goes in after the lift but before the stars, the top plug goes in last.

 

Here`s a few 30mm mines, these used a piston (single hole) and a top plug disc with 3g of lift. The camera position was a bit close to get the full effect but they managed a decent height.

 

http://youtu.be/szIEUyrjqdc

Edited January 19, 2015 by Col

[stix]

Tissue tends to create burning debris. A decent top (pressure building) plug can be made by scrunching up a bit of kraft, stuffing it in a spare tube and compacting it with a solid rammer.When you push it out it`ll expand a tad.

For mines, i use a piston or disc with one or more smallish holes punched in it to let the fire through to ignite the stars, it goes in after the lift but before the stars, the top plug goes in last.

 

Thanks Col, If I remember correctly I could use borax soaked paper to make it flame resistant? I made some years back for model rocket parachute ejection. The piston disc with holes punched in it sounds like a good idea, which must have some benefit that i can't comprehend yet.

 

I reckon I'll try the your first suggestion as a starting point - I have the kraft paper and a piece of off-cut tube sitting about 5mtrs away... hmmmm.... Do you wet it slightly? and how thick do you reckon? around 1/2 inch?

 

btw. I would love to do lots of test myself, without bothering anyone with seemingly simple questions, BUT I don't have the 'testing space" where I live. At least not at the level I would like.

 

Cheers.

 

[EDIT] Like those a lot Col. What was the noise in the background? Echo?... It sounded a lot like a train going past.

Edited January 19, 2015 by stix

[Col]

compress it dry like bentonite. Might take a few goes to figure how much paper to use but it only needs to be 4-5mm thick. The piston disc acts like..a piston it helps to shove the stars out of the tube evenly and generally with a narrower spread, ie more up than out.

[stix]

compress it dry like bentonite. Might take a few goes to figure how much paper to use but it only needs to be 4-5mm thick. The piston disc acts like..a piston it helps to shove the stars out of the tube evenly and generally with a narrower spread, ie more up than out.

 

Ok, I do understand the concept of a piston, but can we please get this straight.

 

Is it correct to say that the piston disc is the only disc required. That is, the piston disc with hole/holes in it, sits above the charge, then the stars sit on it loosely? so no need for another disc above?

[Col]

piston disc goes on top of the lift, stars in next and the plug disc on top of those. 2 discs but the plug disc is thicker. I find pizza box cardboard good for the piston disc, make it slightly oversized and crimp the edge so it resembles a bottle cap. Punch a 3mm hole in the middle and push it down into the tube until it runs into the lift. The 30mm mine pistons were made from 2 discs with a short section of cardboard tube glued inbetween so it looked like a mini cable reel. A disc with a hole is plenty for a 3/4".

[stix]

Thanks a lot for that info Col. Now I'll just have to experiment myself.

 

Cheers.

[Col]

dont forget the camera

[FlaMtnBkr]

If you are just going to make it and light it you don't need anything real fancy. I just side fuse the tube, put some BP in, drop in the stars, and go light it. If it's going to be a couple hours then push a piece of kraft paper on top so it won't spill.

 

If you are making them for a show or to keep around for a while then the methods mentioned by Col are more appropriate. I do what I mentioned when testing stars or for a quick fix. Kinda sounds like that is what you are going for and it doesn't need to be overly complicated. And you can just add a little bit more BP If they aren't going high enough. In that small size they don't need much.

[nater]

I agree with FlaMtnBkr. For a quick mine to test stars, I just add a little BP and the stars to an 1" cardboard mortar from a reloadable kit which I drilled a hole in the side for a fuse. Easy and fast, it does the job.

 

Personally, I would not worry about making a nice reloadable mine smaller than what would fit in a consumer mortar. There is an article or two on Skylighter about making mini mines with small stars or effect fuse.

[spitfire]

What FlaMtnBkr said. And nater. If your stars aren't going high enough, there might be a problem with you BP...? You are using paulownia C so that can't be the problem. Is your BP milled well and long enough...? Is it corned? (i assume, but hey i've seen it before it wasn't) When you use a good quality BP just dumping the lift and stars in a tube should be sufficient. I always cap it with a cardboard disc or paper wadding just to prevent spilling or accidental igniton. Good luck and let us know the results!

Edited January 19, 2015 by spitfire

[Col]

I figured as its his first mine he might as well go the whole hog Its all good experience and it doesnt take much to make a disc or two. I only make reloadables (wifes calls them "onions") for 2" and above. The 30mm`s in the clip are bottom fused (blackmatch and igniter)) but have about the same star load as a 1.75" festival ball but less fiddly to make.

[gregh]

I do what I mentioned when testing stars or for a quick fix. Kinda sounds like that is what you are going for and it doesn't need to be overly complicated. And you can just add a little bit more BP If they aren't going high enough. In that small size they don't need much.

 

I do the same thing!! It's quick, easy, and in less than five minutes, you have something to satisfy that need. Of course, I tell the wife, "I am testing things."

 

There is also a tutorial on skylighter showing the pistons as well.

[stix]

Thanks for all the great replies. I had to "Like" them all.

 

What I've decided to do is use 2 discs - bottle cap shapes as Col suggested. A perforated one above the charge, then add the stars (small gumnuts at this point) and then finish with the other solid plug. The cardboard will be pizza box, It seems I already have a good supply of it

 

I'll do this first test in my backyard, it shouldn't attract too much attention. From that I should have enough info to use my stars in the "real" version. Obviously the first test won't tell me if the stars would have lit properly, but at least I'll have a good idea about how much of my homemade bp to use.

 

btw. My bp is screened/riced. I'm going to stick with that method because at least it is a known constant. I should be able to test this within the hour or so.

 

Cheers.

 

[EDIT] I did actually read the skylighter article some time back but lost the link and forgot some basics - just read it again and it's also useful.

Edited January 20, 2015 by stix

[stix]

TEST ONE RESULTS:

 

I used a level 1/2 teaspoon of lift. Certainly a bigger report than I expected! but not that big. I reckon the "double discs" contributed with the compression, which is good - in a way. It was hard to tell, but the "mock stars" took about 6-7 secs before reaching the ground. The stars would have been long gone burned out by then I would think.

 

I'm done with testing - so, what to do next for the "real one"?

 

I'm thinking: 1. use less lift, or 2. don't use the perforated disc above the lift, and just the plug on top.

 

What do you think?

 

Cheers.

[Col]

Best bet is to make one of each type using the same amount of lift and compare the three

1: piston + plug disc, 2: no piston + plug disc 3: no piston + no plug disc

[wildcherryxoxo]

Im with Col, keep the lift the same. Once you have a configuration that you like well, you can tweak your lift for that configuration.

Also, vids or it didnt happen!

[spitfire]

 

Also, vids or it didnt happen!

Or... leave evidence on the internet... as proof you did something you are not allowed to.

[enanthate]

Or... leave evidence on the internet... as proof you did something you are not allowed to.

... As many of us have done for a while - we're still around

Its fine as long as you use your head a bit.

[MondoMage]

I'm thinking: 1. use less lift, or 2. don't use the perforated disc above the lift, and just the plug on top.

 

What do you think?

 

Cheers.

 

 

I'd go with the other recommendation - test multiple configurations. In pyro there is no "one size fits all" that applies equally to everyone. You'll need to tailor your processes and techniques to what works best for you. You can base your starting point off of what other people are doing, but that doesn't mean you can't tweak things and make them your own.

 

I'm not an old hand at this by any stretch of the imagination, but all of the gurus I know are always tweaking things to see if they can find a better way to accomplish something, or come up with a better effect.

[stix]

 

I'd go with the other recommendation - test multiple configurations. In pyro there is no "one size fits all" that applies equally to everyone. You'll need to tailor your processes and techniques to what works best for you. You can base your starting point off of what other people are doing, but that doesn't mean you can't tweak things and make them your own.

 

I'm not an old hand at this by any stretch of the imagination, but all of the gurus I know are always tweaking things to see if they can find a better way to accomplish something, or come up with a better effect.

 

Thanks Mondo, I agree that we all have to individually tailor our processes, it's good to have this resource (forum) as a starting point.

 

I'll be doing the 3 tests this weekend. I think I'll cut back on the lift from 1.3g to 1g and keep that as the constant.

 

I'm still not sure how many/much stars to use? I admit that I was pretty slack making these as in the size - They are certainly not 1/4" cubes, but similar volume. If I go ahead with the 3 tests that would be around 5gms (approx. 1/2 a tablespoon) of stars per test.

 

I'm not sure if that's enough, or just do 2 tests instead?

 

[EDIT] Of course i don't wish to be spoonfed, but it's around 1/2 a tablespoon of spoonfed stars per 5 grams - yum

Edited January 23, 2015 by stix

[Col]

Rule of thumb is to make the height the same as the id, a piece of the tube makes a good measuring scoop.

[stix]

I've finally done the 3 tests.

 

Firstly, don't be alarmed by the apparent close proximity of the trees - not as close as it looks and very wet after 2 days rain. I also had a water hose at hand just in case. It wasn't where I originally planned to do the tests, and therefore I couldn't get back far enough to video it properly, but good enough to make an reasonable analysis.

 

The tests were done as Col suggested (a different order though)

 

Winokur #20 Glitter. I used 1 gram of lift, and approx. 5grams of 1/4inch cut stars in each.

 

Test 1: No perforated piston and no plug disc

Test 2: No perforated piston, but with plug disc

Test 3: Both perforated piston and plug disc.

 

http://youtu.be/jBk2jCoV1G0

 

I liked the result of test 2 best. Test 3 was certainly "bigger & higher" but I wasn't back far enough to video it all properly and perhaps some of the stars blew blind?

 

Good results though, in that I can use this info for testing other stars - and um perhaps in wider surrounds.

 

Thanks for everyone's help and ideas.

 

Cheers.

Edited January 28, 2015 by stix

[spitfire]

Well, your stars functioned well, your lift was perfect. I guess your stars where small or just a few? This particular stars is most beautiful in ''larger'' objects. But, it worked like it should! Congrats.

[stix]

Well, your stars functioned well, your lift was perfect. I guess your stars where small or just a few? This particular stars is most beautiful in ''larger'' objects. But, it worked like it should! Congrats.

 

Thanks spitfire - Yeah, I'm pretty pleased with the results for my first ever stars. I reckon they could definitely burn longer by adding more NaHCO3 - also fiddling with slower charcoals would also be interesting.

 

I was a bit slack in my cutting efforts and most of the stars were "flatish rectangles" than cubes. As a result they were on the smallish size approx. 25 or so in each mine. Next time I will take more care and setup a simple roller guide.

 

Thanks for your original post: http://www.amateurpyro.com/forums/topic/9514-kings-glitter-as-i-call-it/ now I'm pretty much hooked on glitters . I'll enjoy refining this, and then perhaps try it in a 2 1/2" inch shell on the end of a rocket .

 

A lot of work to do though before I get to that level but it's a goal to work towards.

 

Cheers.