At last -success

[Merlin]

I have been making 3 and 4 inch cylinder shells.

Last year all my shells were broken with MCRH and they were good. This 4th I made only 4 cylinders just like last year. My spiking has improved a bit but this time after I made the first shell I decided to add 5,3,2 booster. The first shell BP only was like last years shells but the boosted shells were very symmetrical and the patterns very large. They had a somewhat professionalappearance. They were great and everyone noticed the dramatic improvement.

I dont know if its kosher to add booster to cylinder shells but it sure makes a better display.

Just wondering if any of you all add booster to cylinder shells?

[greenlight]

I always add a small amount of KP whistle booster to all the cylinders I make now and have noticed the same improvements you describe.

 

When I burst my earlier cylinders with just BP the stars didn't really have the "oomph" and they drooped quite early in their flight time.

Edited July 5, 2018 by greenlight

[greenlight]

I can add to what was said now I am home:

 

I think that cylinder shells need a stronger burst (booster) compared to ball shells do for two reasons, assuming the spiking and pasting strength of each is the same:

 

1* The cylinder has more volume than the same size sphere. You can get more powder and stars in a cylinder shell because of this. But this also means the surface area is more which would make the cylinder slightly weaker, it is not as compact as a sphere.

 

2* A sphere is the strongest shape as there are no weak points compared to the straight ends of a cylinder shell. The stress on a sphere is distributed to it's entire surface.

 

I have read that spherical containers can withstand twice as much pressure as a cylinder which would mean that the ball shell would burst with more force compared to a similar sized, similarly spiked cylinder shell.

This is just my opinion I may be wrong though.

Edited July 5, 2018 by greenlight

[Merlin]

Thanks for your reply. What you say is reasonable I just never thought about it in that way. I have never made whistle mix as I admit I am chicken to press it in rockets. I suspect 5,3,2 is the weakest booster. I might try 35,35,30 listed as "Spanish booster. Perc, kno3, Al. That might be more similar to whistle. Thanks again for your reply. Hope you had a great 4th!

[memo]

i use slow flash on my small shells 50 25 25 works well as a booster. in a 2 "i use 3 grams and a 3 " i use 5 grams . these are cylinder shells.

 

memo

[Merlin]

Memo is that 50 25 25 nitrate, Al, S or perc, Al, nitrate?

[memo]

50 nitrate , 25 sulfur 25 black al . the nitrate need to pass a 100 screen

[Baldor]

I mill the nitrate and the sulphur together, sieve it, and then add the Al.

[Merlin]

That sounds good. Do you add boric acid for stability? I make my shells 2-3 months before use.

 

I mill the nitrate and the sulphur together, sieve it, and then add the Al.

[Baldor]

No, I only make what I need and use it in little time. I don't like to store it. But a little boric acid will not harm the comp.

[MadMat]

I have another tip since I have made a lot of 3" cylinders... 3 inchers are a little on the small side for MCRH. I use only granulated BP and have been getting decent breaks. Your BP has to be pretty hot to do this without booster. I have, in the past, had batches of BP that weren't hot enough, so I added a small amount of flash.

[Merlin]

I have good hot bp but I pretty much use mcrh for lift and burst in 3's and 4's. How long does it take y'all to make shells for the 4th? Maybe Im just slow but to crank out 30-40 shells I have to start building in advance.

[memo]

for my lift and burst i use fairly hot bp boosted with slow flash, try it i think you will like it better than mcrh . mcrh were mostly used in ball shells. they needed the bulk to fill up the space and lite weight

[dynomike1]

I use 70/30 in all my shells Per, Al Sulfur, and Ti.

[PhoenixRising]

As a small time hobbyist I'm tired of wasting my good BP on small cylinders, so KP on rice hulls is probably in order this next 'season'.

 

Try some Chinese Burst if you want, it's a good comprimise between power and brightness (if you like a good flash) plus it's just fun to do something different once in a while.

 

Chinese Burst:

40 KP

25 Mg/Al (anything from 80 to 325 is okay with finer being faster)

15 Al (dark)

20 Sulfur

 

and here's another one that will likely act like whistle mix, being there's no metals it 'probably' won't make much of a flash. This 2nd formula I have not tried although I have tried the first one.

Chinese Burst 2:

40 KP

35 KNO3

25 Sulfur

 

In my experience, Spanish booster is the most practical and effective. The nice thing about Spanish booster is that the nitrate does not need to be milled (maybe just light blade milling), just mix it rough and it's good to go. It's a little more powerful than Chinese burst without being any brighter. I personally think 5-3-2 is good for bigger shells or ones that don't need much boosting to begin with, but I do like the nice low pitched report it tends to give compared to other formula.

 

IMO, the balance needs to be struck between brightness and burst size.

 

If your burst isn't big enough (all other things being equal and good) then increase the booster. If the booster is too bright, though, it can dissorient your eyes and possibly make the star effects look less brilliant. In such case you either need a brighter star formula or a less bright burst. It's all a matter of balance and personal taste, only testing will let you know for sure.

 

I do think it would take quite a lot of booster to really overtake the brightness of the formula we use today, most being metal fueled, I can imagine more delicate effects and/or organic formula possibly suffering due to the inclusion of bright boosters. Very interested to look into whistle mix for such applications, although now this second Chinese formula might just fit the bill.

[Merlin]

Yall probably are very well aware of the increased efficiency of 5,3,2 if one actually ball mills the kno3 and S. I ball milled it as I would for BP and then diapered in dark aluminum. This way I can store the ball milled portion until I need some booster. I expected ball milling would make a faster brew than screen mixed kno3&S. Quite the surprise!! I really cant tell the difference in 5,3,2 and straight 70/30 in terms of power. I am torn between figuring out the correct amount between the milled and screen mixed. I used a teaspoon in a 2.5 cylinder as booster. It broke really hard but still had star ignition. Does anyone use KNO3 booster and do you simply use diapered components without ball milling?

Please note I am adding Al by diapering. If someone is stupid enough to ball mill all the components they likely wont live. Milled this stuff is very powerful surprisingly so.

[kingkama]

I used both milled and not. Milled is at least twice powerfull and fast but is nedeed a less than 5 nm Al or 45nm Mg or if you like a mix of both in the best proportion. I found the metal mix close to a 70/30 but i think per(chlorate) are stronger. Edited July 22, 2018 by kingkama

[Mumbles]

Anything with nanometer metal is probably going to be pretty strong.

[kingkama]

Oops pardon I intend microns not nanometer I messed up with symbols.