14 replies to this topic

[Atom Fireworks]

Hey guy's newbie here, first of all how are you all doing????

I am a little confused on the matter of compatables and incompatables. Basically b4 i go ahead n have a go at pyro i would like to no a little about what works and what doesnt as i dnt intend on loosing limbs. The main coneard for me is the star mixes, the say dont mix a chlorite with anything containing sulfur, now does this also include perchlorite's????? also i no that megnesium reacts with water from school day chemistry, wouldnt rolling stars using water and dextrin to bind it cause a reaction???? Ime sorry if i have asked a stupid question that has been asked hundreds of times b4 just i cnt find the info that i need. Basically i need a doos, n dont's off you pro's.

Many thanks Jay,

P.s i cant come to the leed's meet as i have nowhere to stay and i am not loosing my licence for a few bevvies.

[Atom Fireworks]

Sorry i meant chlorate's

[Arthur Brown]

Firstly please be very careful because chemistry is totally unforgiving about bad spag. One letter out can be a different chemical! Please use full words not txt spk. If you read lots of formularies and read several hard copy books, then most of the usual incompatibilities will be pointed out to you as you procede.

[Vic]

I have found this to be a good reference point.


List from Bill Ofca article sited by Lady Kate:

The following is a list of chemical combinations known to cause
sensitivity problems.

Next to each listing are letters to indicate
the types of sensitivity.

The code key is given as follows:

F = Friction
HY = Hygroscopic
I = Impact or Shock
SP = Spontaneous Combustion
U = Unstable (poor shelf life, slow decomposition or unpredictable)

AVOID THESE COMBINATIONS OF CHEMICALS

1. Potassium Chlorate & Sulphur, Sulphides, or Sulphates - F, I, SP, U

2. Barium Chlorate & Sulphur, Sulphides, or Sulphates - F, I, SP, U

3. Potassium or Barium Chlorate & Ammonium Compounds - F, I, SP, U

4. Potassium or Barium Chlorate & Calcium Carbonate - F, I, U

5. Potassium or Barium Chlorate & Aluminium - F, I, U

6. Barium or Potassium Nitrate & Aluminium (when wet) - U, SP

7. Ammonium Perchlorate & most Nitrates - HY, U

8. Untreated (coated) Magnesium & any Oxidizer - SP, U

9. Barium Nitrate & Sodium Oxalate - HY, U

10. Barium or Potassium Chlorate & Sodium Oxalate - HY, U, F, I

Certainly this is not all-inclusive, but gives some fairly common
combinations.

[MDH]

I have found this to be a good reference point.


List from Bill Ofca article sited by Lady Kate:

The following is a list of chemical combinations known to cause
sensitivity problems.

Next to each listing are letters to indicate
the types of sensitivity.

The code key is given as follows:

F = Friction
HY = Hygroscopic
I = Impact or Shock
SP = Spontaneous Combustion
U = Unstable (poor shelf life, slow decomposition or unpredictable)

AVOID THESE COMBINATIONS OF CHEMICALS

1. Potassium Chlorate & Sulphur, Sulphides, or Sulphates - F, I, SP, U

2. Barium Chlorate & Sulphur, Sulphides, or Sulphates - F, I, SP, U

3. Potassium or Barium Chlorate & Ammonium Compounds - F, I, SP, U

4. Potassium or Barium Chlorate & Calcium Carbonate - F, I, U

5. Potassium or Barium Chlorate & Aluminium - F, I, U

6. Barium or Potassium Nitrate & Aluminium (when wet) - U, SP

7. Ammonium Perchlorate & most Nitrates - HY, U

8. Untreated (coated) Magnesium & any Oxidizer - SP, U

9. Barium Nitrate & Sodium Oxalate - HY, U

10. Barium or Potassium Chlorate & Sodium Oxalate - HY, U, F, I

Certainly this is not all-inclusive, but gives some fairly common
combinations.

This is good advice, but it is also a general rule of thumb simply to look up the properties of your chemicals online and compare them. For instance, mixing a strong base like a peroxide or a hydroxide as a buffer with something more acidic (Say, you're using an acetate as a fuel or a benzoate) will cause them to react if they become wet, or they will anyway over time, rendering your composition useless. A good example of this is ascorbic acid and sodium benzoate, which while no compositions simultaneously employ, produces pure benzene. That sets the stage for many other potential scenarios.

In particular, the sensitivity of chlorates and sulfur is because of the formation of small amounts of sulfuric acid in the composition reduces chlorate to the powerful oxidizer chloric acid. The few factories who still use these ingredients together tend to treat them with small amounts of carbonates, which have some effect in neutralizing sulfuric acid which forms over time.

[digger]

iv always used the rule dont use Chlorate's (apart from making my igniters) but these two (which iv used in other comps) i never knew about. thanks for the info

Nitrate / Aluminium is well documented (remember the old boric acid buffer for this)
The other one is less obvious, just think of the double decomposition reaction which would make the insoluble barium oxalate and the very soluble and hygroscopic sodium nitrate, very soggy stars (poor shelf life).

By the way don't rule out Chlorates. Some great colours can be produced which are very easy to ignite. Even the simplest chlorate formula are good. It is hard to make a poor colour as long as the incompatability rules are followed.

Edited by digger, 24 September 2009 - 11:21 PM.

[wjames]

digger:
"Nitrate / Aluminium is well documented (remember the old boric acid buffer for this)"

How would you compare this to Nitrate/Magnesium?


(pehaps needs an entirely different topic ??)

[digger]

digger:
"Nitrate / Aluminium is well documented (remember the old boric acid buffer for this)"

How would you compare this to Nitrate/Magnesium?


(pehaps needs an entirely different topic ??)

In a single word mild.

Magnesium powder is far more reactive with nitrates. This topic has more than likely been covered before a fair few times. You will need to coat the magnesium with either potassium dichromate or linseed oil if you wish to use it (even with solvent based binding systems). Boric acid will not work as a buffer as it will attack the magnesium. Even straight water will attack magnesium powder!

[Atom Fireworks]

Cheers guy's thats cleared it up a little for, i have had my dad print of around a thousand pages of some site he found that goes through everything from fuses, shells fountains, bp grades an all the different ways of mixing and different chems you can use so on and so on, just i still cant find weather a chlorate is the sameas a perchlorate? i keep getting the message dont use chlorates with sulfur but does this mean perchlorate aswell, can anyboby explain this to me,

Many thnks, Jay

[mike_au]

Perchlorates are not the same as chlorates, however depending on the source perchlorate may have chlorate contamination.

It is always a good idea to use chemicals from a reputable supplier and test (hit with a hammer, grind on concrete) a *small* amount of the composition before working with it.

Make sure you aren't near anything flammable while testing.

[Atom Fireworks]

Perchlorates are not the same as chlorates, however depending on the source perchlorate may have chlorate contamination.

It is always a good idea to use chemicals from a reputable supplier and test (hit with a hammer, grind on concrete) a *small* amount of the composition before working with it.

Make sure you aren't near anything flammable while testing.

Cheers mike i will do that, so whereas i cannot mix a chlorate with sulfur it is ok to mix with perchlorate if it is not contaminated? Just abit concearned as i intend to use bp coated hulls as burst charge but i am thinking of making my stars with perchlorate mixtures.

[portfire]

Cheers mike i will do that, so whereas i cannot mix a chlorate with sulfur it is ok to mix with perchlorate if it is not contaminated? Just abit concearned as i intend to use bp coated hulls as burst charge but i am thinking of making my stars with perchlorate mixtures.

KP burst charge has sulphur in the formula. (KP is a KClO4 based burst) While it's not as sensitive as ClO3 & S, precautions should still be taken, as you would with any composition. It is however very common to use KP burst, just DONT ballmill it. You can ballmill the C & S then screen the Perc in.

Regarding your question, you'll be fine, if your still a little worried you can always separate the burst from the stars with tissue paper, which again is common practice.

[Atom Fireworks]

KP burst charge has sulphur in the formula. (KP is a KClO4 based burst) While it's not as sensitive as ClO3 & S, precautions should still be taken, as you would with any composition. It is however very common to use KP burst, just DONT ballmill it. You can ballmill the C & S then screen the Perc in.

Regarding your question, you'll be fine, if your still a little worried you can always separate the burst from the stars with tissue paper, which again is common practice.

Thanx for the info much appreciated, glad theres a forum on this otherwise i could see many people getting hurt by rushing into it without any decent info.

[spanner]

Thanx for the info much appreciated, glad theres a forum on this otherwise i could see many people getting hurt by rushing into it without any decent info.

HERE'S some good info from Ofca, regarding safety.