1569 replies to this topic

[maxman]

Yes but how much of the 12 hr bp? Just to get an idea how much should be used with a mortar / shell fit like that

[Wyvern]

Oops forgot about that, i use 27g lift for my 3" shells which usually sees them up to a good 150-200 feet

[maxman]

Ah right, Thats about an ounce I think. I would have thought that would be enough even with a 7mm gap. I use 15g of 3FA equiv homemade for my 2 1/2" Do you know if you used 2FA or 3FA?

[Wyvern]

To be honest im not realy sure, having never used commercial bp im not sure of the grades avalible and thier homemade equivilents, thgap is 7mm all the way round so alltogether its quite a bit of space so you can imagine the ammount of pasting that needs to be done but it works fine when i do it properly, it just takes a while.

[Pyromaster2003]

Thanks for sharing the comp, need to get some trisulphide before i can try it out for myself. You can get some nice effects just using c and al as iv found before.

Why not just use smaller diam mortars? Are your mortars too big or your '3 inch shells' not 3 inch?

Edited by Pyromaster2003, 20 April 2007 - 12:43 PM.

[Wyvern]

The mortars i use are just over 3" and the shells are smaller too which doesnt help im going to try a different place to buy thr hemis and switch from plastic to cardboard and see if they fit better, the ones i buy are from pyrocreations and the mortars come from pyrogear.net

Edited by Wyvern, 20 April 2007 - 01:11 PM.

[Pyromaster2003]

Forgot to mension before when i was into shell making i was working on a 2 inch can, the mortar was too big like yours so i simply rolled thick cotton wool around it in the middle, then tightly wrapped one strand of masking tape around the middle of the clump/rolled cotton wool, this was then a nice fit in the mortar (when placed in the top it didnt slide down it needed a gentle push to the bottom - tighter fitting shell means better height and less lift needed, obviously not too tight though). It will work with round shells aswel, not tried it but if done correctly it will work, just wrap the wool around the centre of the shell horizontally (use plenty) then one thin wrap of masking tape (and possibly string) in the middle to hold it in place during lift.

[cooperman435]

Depending on your metods for attatching the lift charge (if you make shells like the commercially available ones or put lift into the tube loose) and your fusing method( top fused or ignited by the lift charge)you can always ram a wad of newspaper down the tube between the shell and lift charge creating an almost air tight wad beneath the shell.

I use this on my top fused cannister shells and put a wrap of craft to make a tube round the shell that sticks out top and bottom then put a 2" wad of paper under the shell then the lift charge and tie it up to hold the lot in.

when this is done correctly I have to use less than 1/2 the lift I do without the wad of paper.

[treefingers]

This is my first 2" canister shell that I fired a minute ago. Stars were 1/2" pumped Winkour 20, Purple and Green and I used granulated BP and a little flash for the break charge.

http://pyrotechnics....iles/2shell.wmv

Anyway quite a few things went wrong but overall I guess I was pleased.

First of all the lift was slightly poor. The shell weighed about 90g so I used 9 grams of lift, but as my lift wasn't so good the shell didn't reach very high.

Secondly the booster I used, which was a drinking straw with a little flash powder in, was thrown out of the shell as the BP blew first. This is why there is a second louder report after the inital break.

Finally the green stars didn't ignite and the purples weren't very visible being pretty much over shadowed by the Winkour 20's. Also I made the mistake of placing them togther so as they fall they are grouped together. Anyway i'd appreciate any advice on how to improve on my next shell.

[pudi.dk]

I actually liked how it broke flatly and a report after the break. But you're right, the apogee was a little close to the earth.

Edited by pudi.dk, 22 April 2007 - 12:07 AM.

[Bonny]

The Comet will go in facing upwards and will be ignited by the hot rapidly expanding gasses...

I would like to attach a small comet on a 1" bottom fired shell. Would the lift charge ignite a comet sitting on top?If not, I was thinking, would a strip of BP slurry up the side of shell be a possible solution?

[cooperman435]

It would be easier and much better to put the quick match into the comet then down to the lift like a top fused shell

[Creepin_pyro]

It would be easier and much better to put the quick match into the comet then down to the lift like a top fused shell

Al long as the comet is primed properly, there's no need for any passfire. The lift gasses will light the comet just fine.

[treefingers]

Made a few shells in the last few days with varying sucess. This is one of the ones that seemed to work out quite well.

Shell was 2 3/4 ID Canister shell with Winkour 20, Green and Purple and a few bits and bobs of old stars I needed to get rid of.

Break was around 10g of Bp coated rice crispies with 2-3g flash plus granulated Bp between stars.

http://s85.photobuck...ketspics002.jpg
http://s85.photobuck...ketspics005.jpg
http://s85.photobuck...ketspics006.jpg
http://s85.photobuck...urrent=1008.jpg

Video..
http://pyrotechnics....shellw20cut.wmv

Although I was quite pleased with this shell I was quite dissapointed with the colours. Green was Shimizu forumla which came out more white then anything and the purple was slightly better but still not great.
Any comments/critisisms?

[KarlosH]

Hallo. I hawe a guestion for fireworks experts. I seen interestin effect on the www.hanabi.co.jp web and this effect is called bee(hachi). I try making simillar effec as hummers, and tourbillions but nothing similarity.
I tryed not stabilized small rocket, but this roctket flew straight. I want obtain small tubes, which flying in spiral trajectory, like in this video from japan(fireworks and explosive story).

http://n-joy.cz/vide...aSeXjqOISTzl30/

http://www.hanabi.co...03yamada01m.mpg

Hummers rotating about own axis, and effect producing sound, but not spiral flying.
Tourbillions with one hole on the side(near end of tube) haven´t own propulsion, but only rotation.

Wariants?:
http://img02.picoodl...am_79bf93d2.jpg

This is the effect with one hole with spirall moving:
http://www.srs.ne.jp...abi/Hanabi1.jpg

Please help me. If anybody know this effect send me any information. Thanks, Karel.

Edited by KarlosH, 02 May 2007 - 10:21 AM.