55 replies to this topic

[karlfoxman]

Well, you need to work on the BP. The way you made that didn't cool the solution fast enough to force the KNO3 to rapidly precipitate into *very* small crystals. Try following the CIA method directions more exactly and you'll see what I mean.

I tried out one of those stars I posted about today, using a short 3/4" tube ( trying to dial in the lift for the first few stars ) I used 4 gm of ball milled pulverone. It went up about 25 feet ( I know I can get better though) and the good news, the red pumped star worked perfectly, even in daylight it was brilliant red, like a signal flare, and extinguished before it hit the ground. I fiddled with the Davis delay comp by using 36 mesh charcoal and adding 4 gm of granular ferro-titanium and it makes the delay nice and sparky. I might just go waste a blue and a green star and test my 'mid tube' lift charge ( trying to make 18" long 3/4" candles and want the stars to all reach the same heights ) before hitting the sack tonight.

You candle masters out there... what ratio of lift charge weights do you use for the first star, mid level stars, and the bottom stars ? Do you bother with trying to 'calibrate' the lifts to the tube length ?

I am not a master of candle construction but i have heard somewhere that people dont change the ammount of lift in relation to the tube length. I guess there is a calculation somewhere that will work it out for you. If it was me i would experiment by using different length tubes and testing indervidual stars with the same ammount of lift. Then doing it again till they all seem to go almost the same altitude by adjusting the lifting charges, you could even use dummy stars if you want to save your stars. Can we see a vid of your stars working??

[Pretty green flames]

Not a candle guru either but i use 2 times the ammount of lift for the top star.
My candles usually cosist of 5 shots.
1gram for the top star and around 0.5 (+/- 0.1) for the bottom one. Seems to work good.

[Frozentech]

I am not a master of candle construction but i have heard somewhere that people dont change the ammount of lift in relation to the tube length. I guess there is a calculation somewhere that will work it out for you. If it was me i would experiment by using different length tubes and testing individual stars with the same ammount of lift. Then doing it again till they all seem to go almost the same altitude by adjusting the lifting charges, you could even use dummy stars if you want to save your stars. Can we see a vid of your stars working??

I've made up 3 test star gun tubes, the one I fired the red star today was the shorty, only 3" long, ( 3/4" ID) I made that one up with lift, star, and delay, fused from the top, as in a production candle. The other 2 are a 9" long ( to simulate middle of candle stars) and an 18" ( bottom star ). I know from other star tests that it takes much less lift with the longer tube, I am just experimenting to try for consistent heights from start to finish.

The stars are pretty quick & easy to pump out, so I don't mind burning them up It takes me longer to make decent lift BP than to pump the stars, and they dry much faster than comets, due to that hole through the middle. ( I can squeeze 2 sticks of blackmatch through as the passfire, btw ) I am already dreaming of stacking them in a cylindrical

I will post videos. So far I only have vid of the 3" tube test, and it's sort of silly, because all that shows up on camera is the burst of flame, like a mini-mortar tube lift, and a streak, the star action is all out of the frame. The camera was tripod mounted, next tests will be with handheld camera, hopefully tomorrow, so I can pan and follow the stars.

PS, what is preferred video format here ? wmv ? avi ? mpg ? Seems like no matter what I use, somebody somewhere prefers the others LOL.

Not a candle guru either but i use 2 times the ammount of lift for the top star.
My candles usually cosist of 5 shots.
1gram for the top star and around 0.5 (+/- 0.1) for the bottom one. Seems to work good.

OK, so probably basically double charge for the top star. Thanks. By the way, PGF, your dowels are ready to ship, I just need to take time on a weekday to get them in the post.

[Frozentech]

Well, I ran my 3 tube test, using a 3", 9" and the full 18" tube just a bit ago. The 3" worked pretty well, I caught the red star on video, The other 2 blew blind ( and I do mean *blew* ! ) They sounded like freaking cannons going off, and I am sitting here waiting for the neighbors to complain or call the cops. So, it is NOT a linear scale when calculating lift charge for varying tube lengths in Roman Candles. I was using pulverone, and a pretty hefty 5 gm for the 3" tube, worked well, so I figured 1/2 that for the bottom star... 2.5 gm, and 3.7 for the mid level star. Both of those damn near cato'd the (heavy walled) 2/3" ID tubes. It's winter here in Alaska, and those last two shook snow off the trees all around. I will be posting my "Roman Cannon" vids later today, when I decide where to host them at.

In the meantime, back to the drawing board. Going to cut waaay back on the bottom star's lift charges, and try to calculate a logarithmic table of lift charges... in other words, take a wild ass guess

It does get the adrenaline flowing don't it ????

[sizzle]

Ok, so I'll soon be borrowing a ball mill off a friend and hopefully should be able to get some good lift on the go for candles and aerial salutes, but what size mesh should I use?

Edited by sizzle, 01 December 2005 - 09:33 PM.

[fishy1]

would some of the more energetic star comp work in a candle without lift?
(i read the "mine minadventures" thread, where the stars propelled themselves out 2m or so without lighting the lift.)

maybe with a longer, tight fitting tube.

[sizzle]

I don't have those stars though, and I want to do more than just one type of star in 15 candles to be honest.

[Frozentech]

Ok, so I'll soon be borrowing a ball mill off a friend and hopefully should be able to get some good lift on the go for candles and aerial salutes, but what size mesh should I use?

Sizzle, I use 10 mesh pulverone from ball milled BP for candle lift, it's been working well. It was actually hotter than I expected.

[Amleth]

would some of the more energetic star comp work in a candle without lift?
(i read the "mine minadventures" thread, where the stars propelled themselves out 2m or so without lighting the lift.)

maybe with a longer, tight fitting tube.

While I've no doubt a loose-sitting chrysanthemum #6 star would lift itself out of a candle tube unaided, it'd still be absolutely pathetic (I'm talking something measured in inches). You really do need a real lift charge under it to get a proper height. Also, what with the ramming cycles in a candle, you'd press the star into the delay below, fusing them together somewhat, so it probably would be stuck in place and never take fire on the bottom anyway. Having granulated propellant under the stars means there's air voids there for flame-front propagation even after you've rammed the delay on top of it.

Also, note that you shouldn't be ramming candles as hard as, say, a fountain or rocket. Too much force can crush your lift charge granules into uselessness, but since candles are unchoked and under far less pressure than a lot of devices, you can get get away with less. I use 5-6 sharpish raps with a mallet on 1/2" candles (don't be belting it as hard as you can!). You may find you need slightly more or less on yours, but it's a good figure to start from.

Edited by Amleth, 04 December 2005 - 03:15 PM.

[richard2]

Hi

I have recently been working on some 9 shot candles and have managed to get every shot apart from the first dialled into approximately the same height. Invariably the first shot is only reaching around 3m and I?m looking for around 20m.

The specs are: tubes - length 25cm, ID 12mm, stars - cylindrical 10mm OD.

After the last increment of delay there is only around 3cm of empty tube left. I have tried increasing the lift up to 3 scoops (empty 9mm cartridge) which had little effect. I have also tried lightly ramming a 50:50 mix of polverone:iron powder into the remaining tube, which leaves a nice plug of slag, to no avail grrrrr.

I would like to keep 9 shots as I?m using 3 different star colours. I don?t have much room to play with on star size and if possible would also like to avoid rolling more tubes as I rolled 30 of these.

Has anyone experienced a similar problem and come up with a solution or does anyone have any suggestions that I could try? Should I just be reaching for the rolling board?

Thanks in advance for any replies.

Regards

Rich

[JamesH]

Try placing a cardboard disk between the lift and the star. This disk should be a snug fit in the tube and should have a 1/8" - 3/16" hole punched in the center to communicate fire to the lift charge.
A short length of black match could be placed through the hole if too much of the star is consumed in the tube. The black match would create an air space under the star which will allow fire to pass around it quicker.

Hope that will be of any help in getting that first shot higher. Let us know how you get on.

[treefingers]

Just a quick question that i thought was relavant to this thread...

I'm having a lot of the same problems with getting decent lift on my stars, which I suspect is due to my BP. Anyway I need to do some experimenting to get it right but I've already wasted too many stars and am reluctant to use more. I'm thinking of making dummy stars but i'm unsure as to what to make them from. Can you think of suitable material with roughly the same density of stars that I can use?

[karlfoxman]

Try a concrete mix, I have made inert stars using this and they dry over night. But be careful as they will come back down!

[Frozentech]

Just a quick question that i thought was relavant to this thread...

I'm having a lot of the same problems with getting decent lift on my stars, which I suspect is due to my BP. Anyway I need to do some experimenting to get it right but I've already wasted too many stars and am reluctant to use more. I'm thinking of making dummy stars but i'm unsure as to what to make them from. Can you think of suitable material with roughly the same density of stars that I can use?

I've used cat litter (clean!) other people recommended dry dog food kibbles, but they seemed a little light, it must depend on the brand. Like Karlfoxman mentioned, head's up ! What goes up must come down, and a 200 gram inert shell falling 100 meters on your head could really ruin you day ( or your windshield, etc )

[portfire]

Just a quick question that i thought was relavant to this thread...

I'm having a lot of the same problems with getting decent lift on my stars, which I suspect is due to my BP. Anyway I need to do some experimenting to get it right but I've already wasted too many stars and am reluctant to use more. I'm thinking of making dummy stars but i'm unsure as to what to make them from. Can you think of suitable material with roughly the same density of stars that I can use?

I treefingers. How are you producing your lift, do you have a ballmill.I'll explain how i make my lift for my star gun's ( the stars been tigertail and crys 6)

1# I first mill my charcaol for 5 hours
2# then i mill charcoal/sulphur mix( in the right ratio) for 10 hour. I mill quite alot so iv got some for the future.
3# mill my kno3 for 5 hours
4# then mill the kno3 and the C/S mix for 3 hours.

A small pile of this(1g) burns with a vicious flash
Then what i do next is to ram the powder in a 15mm id carboard tube into 5-10 mill puck's, cruch and grade the powder (use 10 mesh). One gram of this will lift a 10mm crys6 star to a respectable height.
hope iv been some help...dean

Edited by portfire, 26 February 2007 - 04:15 PM.