32 replies to this topic

[Creepin_pyro]

I've made some nice meal pucks, and broken them up into granules for lift. I'm pleased with the results - nice and dense, tinkly china noise when Ihit them, etc. I waited till the pucks were dry (I thought) and then broke them up. I then transferred them into an airtight (I think) container. I was surprised to see them growing little bits of white mould after about a week. Has anyone experienced this? Am I just not drying them properly, or has something gone hideously wrong? The mould does not seem to effect the performance of the granules.

[Mortartube]

Are you sure that this is mould and not KNO3 crystallising out of a still damp puck? An airtight container can cause condensation if it's plastic or metal and that could promote mould growth if you have dextrin etc in your mix.

[Rhodri]

Potassium nitrate is a major ingredient in biological growth media - often known as Stanier's media.

It allows for prolific growth of fungi. I guess you may been seeing some form of mycelium, mucor or penicillium species!

[Creepin_pyro]

It doesn't look like crystaline Kn03. The mould seems to grow in little circles, and is very weak and fluffy. There is dextrin in the mix, but the pucks seemed quite dry - after seeing what happend when I broke up a still moist puck. I think I just need to leave them in the sun longer, and use dessicant in the container. Is there any other way to avoid condensation?

[lord_dranack]

I have had problems with mould growing growing on bp. however the way I was storing it was kind of asking for some growth. I had slurry of meal powder and 10% dextrin that was stored in an open container over winter, when I don't do much pyro. When I looked at it again it was coverd in white and green mould.
Not much help, I know, but I thought I'd share my story with someone!

[Rhodri]

You could dry the storage atmosphere using the dried silica gel packets that accompany some electrical devices.

You can prevent mould growth by adding 0.5% cyclohexamide (fungacide).
Bacterial growth can be inhibited by using 0.5% chloroamphenicol (antibiotic).

However, you'll find these two difficult to obtain although chloroampehnicol is often a constituent of eye drops.

[Creepin_pyro]

You could dry the storage atmosphere using the dried silica gel packets that accompany some electrical devices.

I think I'll give the silica gel a go - I need to get some with the water level indicator, as I can't tell if the old shoe box ones are still effective (which I doubt)

Thanks for the info. :-)

[bobconan]

bentonite clay aka fire clay is one of the most absorbent substances known. it holds like 35% its weight in water. i fill up a couple socks with it and throw them in the broken freezer that a keep my fireworks in.

[Stuart]

You could by some Calcium Chloride too from DIY stores. This stuff is disgustingly absorbent

[novacat14]

I recently made some lift powder, using the directions found on the unitednuclear site. I was shocked to find that the powder was horrible under powered. I used 15 grams and i could not launch a 8 gram arial more that 1 meter. I was a bit disappointed, I milled the BP for 3 hours, i have more milling now and am going to keep it in there for 4 maybe 5 hours to see if it helps.


The portions i used are
KNO3~75grams
Charcoal~15grams
Sulfer~10grams

This is correct right? After the BP was milled i added dextrin and a small amount of water so i would have granuals(spelling?) of BP.

Any thoughts on where i went wrong, and i know BP is not a strict science, just thought I'd ask before wasting more chemicals.

Many thanks for all the help!

[Rhodri]

I recently made some lift powder, using the directions found on the unitednuclear site. I was shocked to find that the powder was horrible under powered. I used 15 grams and i could not launch a 8 gram arial more that 1 meter. I was a bit disappointed, I milled the BP for 3 hours, i have more milling now and am going to keep it in there for 4 maybe 5 hours to see if it helps.


The portions i used are
KNO3~75grams
Charcoal~15grams
Sulfer~10grams

This is correct right? After the BP was milled i added dextrin and a small amount of water so i would have granuals(spelling?) of BP. 

Any thoughts on where i went wrong, and i know BP is not a strict science, just thought I'd ask before wasting more chemicals.

Many thanks for all the help!

What form of charcoal were you using? BBQ bricks or Willow for example?

[BigG]

I recently made some lift powder, using the directions found on the unitednuclear site. I was shocked to find that the powder was horrible under powered. I used 15 grams and i could not launch a 8 gram arial more that 1 meter. I was a bit disappointed, I milled the BP for 3 hours, i have more milling now and am going to keep it in there for 4 maybe 5 hours to see if it helps.


The portions i used are
KNO3~75grams
Charcoal~15grams
Sulfer~10grams

This is correct right? After the BP was milled i added dextrin and a small amount of water so i would have granuals(spelling?) of BP. 

Any thoughts on where i went wrong, and i know BP is not a strict science, just thought I'd ask before wasting more chemicals.

Many thanks for all the help!

15 grams should lift 8g shell way up.... In addition to Rhodri questions, you will need to tell us what is your shell and mortar id's...

[Yugen-biki]

I know this is one of the biggest problems a beginner shell maker confronts. I have read a lot of questions on the internet by beginners who have had the same problem. I had the same problem when I first started takeing interest in shells.
This is my experience and thoughts about lift:

The ingredients ratio is not as important as the partickle size. I use the standard 75:15:10 ratio with good results, but there are compositions optimized for firing aerial shells from mortars.
I foud one formula in a composition database some time ago. Unfortionally I don't have the link, only the ratio. The formula is orginally from "Pyrotechnics Guild International" and is called "PGI optimum":

74 KNO3
14 C
12 S

If you are using "bad" BP as lift I foud that a lose powder is better then granules. Bigger granules produces slower (more gentle) gas developement, and is more often used for larger shells. If the powder quallity is unfit for lift, granulation can make the powder slower. Granules of 2-5 mm size is useable for small shells.

Now to the lift powder it self.
It is possible to make lift useing only a ballmill, but i have found this to be time consumeing and not very efficient. In "The Best of AFN II" there is an instruction how to make "Super pulverone". Useing this method you only ballmill the C and S (only 25% of the total wheight!).
The method is simply described like this:
Dissolv the KNO3 in the smallest volume of water possible and genly stir in the "super fine" milled C and S powder. To help the KNO3, C and S to dissolv properly the mix i heated. (Take great care and don't do anything stupid). The heated mix is then rapidly stirred in to a shilled bath of alkohol. Now the KNO3 will recrystallize clinging on to the C and S particles. KNO3 is not soluable in alkohol and that is why the KNO3 will recrystallize. If done cerrectly the mixtyre will be easy to filter out useing a thin cotton towel. After that, I use an hydraulic press and a tool to make "hockey pucks". This helps to remove the alkohol and water mixture in the wet powder. I let them dry for a day or three and then i gently make granules useing my hand. Then I leave them to dry completely. The granules becomes rock solid, and the "pucks" make a ceramic sound when tapped on. This way you don't have to use dextrin and the particler are forced closer together to enhance the burning speed. This method is somethimes called the "CIA method".
I STRONGLY RECOMMEND "BEST OF AFN 2" FOR BETTER INSTRUCTONS AND NUMBERS ON HOW MUCH WATER, ALKOHOL ETC. YOU NEED. AND MOST IMPORTANT, STAY SAFE!

About the mortar and shell diameter. If your lift powder is not the best, a thighter fit in the mortar becomes more important. The lengt of the mortar, by the way, has not as big impact on the perfomence. When the lift powder is of good quallity, the space between the shell and mortar can be up to 2 cemtimeters without loseing hight of the shell.

And finally some words about the coal. I have the experience that the kind of tree used is not the biggest factor. I use alder coal and have tried pine as well. There are differenses but I find the production method of the final product more important.


I hope this can help some of you readers out there! And remember that this is my experienses and there are lots of ways to make good lift powder. And always be safe. I would hate to read about someone who got hurt when experimenting with pyro.

("Large shells 5" and bigger. Small Shells 3" and smaller")

[BigG]

Yugen-biki ? First, I must say it?s great to read about your experiences, but there are point which I have to disagree upon.

First, I?m not sure what procedure the site in question suggested (Although I do remember reading it and thinking that the information there is in many cases very inaccurate). But using the CIA method should produce significantly INFIRIOR results to ball milled black powder. This is actually mentioned in the original CIA document. The CIA booklet was examining field experiments that assume a situation where you don?t have access to ball mill.

Second, I will agree with you that Mortar size is important. A tight fit is crucial. It you put a shell with OD of 2 inch in a six inch mortar with 15g BP, the shell will not do much. However, if the mortar is 2.1inch, then the shell should climb dozens of meters in the air.


As for the type of wood ? I?m with you; there are plenty of woods that are suitable. Willow is not required. However, if he uses BBQ charcoal with 50% ash, the mixture could be very very poor.

The ratio mentioned in the original post is great. No need to go for PGI optmium. Most use the 75, 15, 10 and get great results.

Oh, and yes, best of AFN is a good set to have. There are a lot of poor articles in them, but a lot of gems as well.

I know this is one of the biggest problems a beginner shell maker confronts. I have read a lot of questions on the internet by beginners who have had the same problem. I had the same problem when I first started takeing interest in shells.
This is my experience and thoughts about lift:

The ingredients ratio is not as important as the partickle size. I use the standard 75:15:10 ratio with good results, but there are compositions optimized for firing aerial shells from mortars.
I foud one formula in a composition database some time ago. Unfortionally I don't have the link, only the ratio. The formula is orginally  from "Pyrotechnics Guild International" and is called "PGI optimum":

74 KNO3
14 C
12 S

If you are using "bad" BP as lift I foud that a lose powder is better then granules. Bigger granules produces slower (more gentle) gas developement, and is more often used for larger shells. If the powder quallity is unfit for lift, granulation can make the powder slower. Granules of 2-5 mm size is useable for small shells.

Now to the lift powder it self.
It is possible to make lift useing only a ballmill, but i have found this to be time consumeing and not very efficient. In "The Best of AFN II" there is an instruction how to make "Super pulverone". Useing this method you only ballmill the C and S (only 25% of the total wheight!).
The method is simply described like this:
Dissolv the KNO3 in the smallest volume of water possible and genly stir in the "super fine" milled C and S powder. To help the KNO3, C and S to dissolv properly the mix i heated. (Take great care and don't do anything stupid). The heated mix is then rapidly stirred in to a shilled bath of alkohol. Now the KNO3 will recrystallize clinging on to the C and S particles. KNO3 is not soluable in alkohol and that is why the KNO3 will recrystallize. If done cerrectly the mixtyre will be easy to filter out useing a thin cotton towel. After that, I use an hydraulic press and a tool to make "hockey pucks". This helps to remove the alkohol and water mixture in the wet powder. I let them dry for a day or three and then i gently make granules useing my hand. Then I leave them to dry completely. The granules becomes rock solid, and the "pucks" make a ceramic sound when tapped on. This way you don't have to use dextrin and the particler are forced closer together to enhance the burning speed. This method is somethimes called the "CIA method".
I STRONGLY RECOMMEND "BEST OF AFN 2" FOR BETTER INSTRUCTONS AND NUMBERS ON HOW MUCH WATER, ALKOHOL ETC. YOU NEED. AND MOST IMPORTANT, STAY SAFE!

About the mortar and shell diameter. If your lift powder is not the best, a thighter fit in the mortar becomes more important. The lengt of the mortar, by the way, has not as big impact on the perfomence. When the lift powder is of good quallity, the space between the shell and mortar can be up to 2 cemtimeters without loseing hight of the shell.

And finally some words about the coal. I have the experience that the kind of tree used is not the biggest factor. I use alder coal and have tried pine as well. There are differenses but I find the production method of the final product more important.
I hope this can help some of you readers out there! And remember that this is my experienses and there are lots of ways to make good lift powder. And always be safe. I would hate to read about someone who got hurt when experimenting with pyro.

("Large shells 5" and bigger. Small Shells 3" and smaller")

[novacat14]

I am using willow charcoal. the ID of the tube is 7/8" and the diameter of the shell is just a few hairs shy of 7/8". It is a loose snug fit, I don't need any force to put the shell in the tube, I just have to let it slide down.