10 replies to this topic

[LuMpY]

Hello
This is my first time writing on this forum, and I would like to say how much the archives have helped me in researching pyrotechnics. I have a couple of qestions to clear a few things up.
I have been reading about making stars and I was wondering what would be the best core for a tiger tail comp, or does it matter?
Also I should be able to get ball bearings from a friend, they are steel, but totally covered in chrome. Does anyone know if this will spark?

Jason H

[Yugen-biki]

As a beginner start makeing cut stars. Rolling stars are maby not for beginners. I use sugar pellets but you can use seeds or something round-ish foud in the citchen. Lead cores may be used for the beginner but is dangerous when it comes back down from the sky! And it?s poisones.

Chrome will spark i quess. I am not sure though. To be on the safe side never mill ingredients together and clean the milling-jar after each chemical. A roul of thumb is to never mill a composition!

Wellcome to the art of fireworks!
/John

[dfk]

I have been reading about making stars and I was wondering what would be the best core for a tiger tail comp, or does it matter?

Hellow lumpy

Your best bet for a charcoal firedust comp, tigertail being one of them is to skip the rolling part and just make cut stars. good choice on begginers comp, these stars are easy fairly safe and give a nice effect.

Just roll your damp comp out on some wax paper, cut into close to even squares as possible and dump into a bowl of meal to prime. thats it, besides letting them dry of course.

If your realy itching to roll use #8 buckshot found im most gunshops, but any small close to round media will work(rice, lentals, other stars)
rolling is most used when a double effect is wanted, IE.. a color changing star.

As for you berings steel will spark, Im not sure about chrome but chrome can chip exposing beare steel. Look around you will find much on this subject. If your worried about sparks use lead.

If you are just starting be sure and read and understand as much as you can on safty of your chemicals and procedures, thers a lot of useful info on this forum.

Hope this helps and welcome

Marcus

[adamw]

Just remember (one of the golden rules in pyro) - what goes up must come down (in some form or other). Using ball bearings could prove very dangerous. I am aprehensive about using lead shot (even though it has been suggested that the lead is consumed in the burning), never mind ball bearings (which I assure you wont melt). Thats gonna hurt!!

For a large core try 6mm PLASTIC 'BBs' ie pellets used in 'Airsoft' guns. Buy the cheap kind ('lightweight' 0.1g) type of the cheapest make possible. You should get several thousand for a few ?/$. They are usually blue, white or yellow in colour.

[dfk]

I figured the bearings were for milling.

*Note to all Dont use bearings for cores uless you live in a desert or like watching your shells from inside.

Edited by dfk, 03 February 2004 - 08:25 AM.

[Stuart]

What ever force was used to push the object up into the air, it will have the same when it comes back down to earth. In other words, if your stars fire up at 100mph, they will come back down to earth at 100mph, that will make a lovely hole in your head. Air resistance is neglible in this case as metal BBs will have very little air resistance

Stuart

[dfk]

If my memory serves, I dont believe this is quite how the physics works.
to get technical,
If the star (or bearing i guess) left the tube at one hundred miles an hour it would immediatly begin decelerating till it actualy stoped, then it would turn back and accelerate toward earth at 9.8m/s. This would go on the till the bearing hit earth or reached its terminal veocity. The TV itself would have to decrease given the change in mass and shape of the burning star (or not, if its a bearing).
The TV of a human is 200km/s so im sure a bearings speed could get up there with the little resistance it has.

Anyway I am not sure of the exact terminal velocity of a bearing but you probably have it right in that their would be some nice holes in your head if you were unlucky enough to find yourself in the path of one of these.

Marcus

[alany]

The terminal velocity of a lead sphere 5 mm in diameter would be about 37 metres per second or around 130 km/hr. That is a suprising figure, but I rechecked the math several times, maybe I goofed though?

[BigG]

Actually, if we want to get to that level, a 1mm lead core going up, is not likely to come down as 1mm lead core. The temperature of a star is usually way above the melting point of lead, and while there is argument whether the lead core completely evaporate or not, there is quite solid proof that even momentous exposure to this temperature will evaporate at least some of the lead. Regular shots made from musket guns where the firepower is in direct contact with the ball, showed that the side attached to the black powder was “eaten” and some of the explanation might be up to temperature. I also believe there is not recorded death from lead core stars.

None-the-less, there are environmental questions about usage of lead. This has lead to the disuse (in the UK) of fishing lead balls under the certain diameter and the disuse of shots above certain diameter. Lead ball are easy to roll and are recommended for beginners, but once mastered, should not be used.

[Stuart]

Actually, if we want to get to that level, a 1mm lead core going up, is not likely to come down as 1mm lead core. The temperature of a star is usually way above the melting point of lead, and while there is argument whether the lead core completely evaporate or not, there is quite solid proof that even momentous exposure to this temperature will evaporate at least some of the lead. Regular shots made from musket guns where the firepower is in direct contact with the ball, showed that the side attached to the black powder was ?eaten? and some of the explanation might be up to temperature. I also believe there is not recorded death from lead core stars.

None-the-less, there are environmental questions about usage of lead. This has lead to the disuse (in the UK) of fishing lead balls under the certain diameter and the disuse of shots above certain diameter. Lead ball are easy to roll and are recommended for beginners, but once mastered, should not be used.

True, but if steel BB's are used then there is a problem.

If my memory serves, I dont believe this is quite how the physics works.
to get technical,
If the star (or bearing i guess) left the tube at one hundred miles an hour it would immediatly begin decelerating till it actualy stoped, then it would turn back and accelerate toward earth at 9.8m/s. This would go on the till the bearing hit earth or reached its terminal veocity. The TV itself would have to decrease given the change in mass and shape of the burning star (or not, if its a bearing).

What you have said there is basicly what I said, unless you misinterpreted what I had said.

Stuart

[dfk]

I might have misinterpreted what you said, I thouht this is what you meant-

[/QUOTE]if your stars fire up at 100mph, they will come back down to earth at 100mph[QUOTE]

Just to clear things up,
jst for instance say it is a 5mm ball and its TV is 37m/s as alany said, it would take it something like 4.2s to reach its terminal velocity when accelerating at a rounded up 10m/s.
so as long as your bearing is shot high enough to freefall for 4.2 seconds it would be traveling at 130km/h, no less no more.

Edited by dfk, 04 February 2004 - 02:51 AM.