Black Powder

Most Commonly Used Blackpowder Formula

Black powder is one of the most commonly used compositions in pyrotechnics.
It's used to lift and break aerial shells, as a fuel in rockets, drivers and fountains, as a base for many Glitter and Steamer star comps.

The same ingredients are used to produce the best & most known, loved & used charcoal firedust stars
Takeo Shimizu's
Tiger Tail, Willow & Chrysanthemum

The most common and widely recognised formula for Black Powder is listed below

ChemicalQuantity %
Potassium Nitrate75

History of Back Powder

The list below shows evolution of documented formulas over the years
1781 BishopWatson - 75.0 - 15.0 - 10.0
1635 British Government - 75.0 - 12.5 - 12.5
1560 Bruxelles Studies - 75.0 - 15.62 - 9.38
1560 Whitehorne - 50.0 - 33.3 - 16.6
1350 Arderne Lab - 66.6 - 22.2 - 11.1
1252 Roger Bacon - 37.50 - 31.25 - 31.25
8th century Marcus Graecus - 69.22 - 23.07 - 7.69
8th century Marcus Graecus - 66.66 - 22.22 - 11.11
The consensus is Black Powder was invented in China while alchemists attempted to create a potion of immortality. The first documented composition resembling Black Powder appears early in the 8th century. Chinese military forces used gunpowder based weapons such as rockets, guns, cannons and explosive grenades and bombs,
Records of fireworks dates back even earlier with stories of Bamboo segments packed with chemicals, tossed into fires exploding or flying off like rockets

Commercial Black Powder
There is quite a process involved in the manufacture of Commercial Black Powder, the ingredients cannot simply be mixed together, this would give a very poor result.
To make good Black Powder the Potassium Nitrate, Charcoal & Sulfur must be intermately mixed by way of a Wheel Mill, usually with the mixture dampened slightly for safety and also to help the Nitrate combine into the Charcoal particles.

After Milling the powder is pressed into cakes to a density of around 1.7 g/cc. The cake is allowed to dry, then broken up and sieved into different particle sizes for different purposes.
For sporting grade powders the grains are tumbled with Graphite to polish or glaze them. These powders are designated with the "g" extension
-12+15 mesh Fg
-16+30 mesh FFg
-20+50 mesh FFFg
-40+100 mesh FFFFg
For blasting powders the grains are tumbled without Graphite and are designated with the "A" extension
-0.3+5 mesh FA
-4+12 mesh 2FA
-10+16 mesh 3FA
-12+20 mesh 4FA
-20+50 mesh 5FA
-30+50 mesh 6FA
-40+100 mesh 7FA
Meal Powder is fine grains of corned blackpowder. This powder is commonly used in pyrotechnics.
-40 mesh Meal D
-100 mesh Meal F
-140 mesh Meal XF
In Pyrotechnics the term Meal Powder usually means Milled Black Powder before corning or granulating.

Black Powder & Hobby Pyrotechnics
Black powder used in Amateur Hobby Pyrotechnics can be made from a variety of methods in different grades and descriptions, all varieties are made with the 75/15/10 formula

Green Mix (Scratch Mix)
All chemicals are ground or milled as fine as possible then screened together well, not milled together.
Green Mix burns poorly, and leaves some residue, It is often used as prime as the hot dross helps ignition of the composion being primed. It is sometimes made into a slurry with water, adding a few percent binder, like Dextrin or Gum Arabic will ensure it sticks to the object to be primed. It can also be dusted onto cut stars during cutting to prevent them sticking together as well as priming them or rolled onto stars as a prime.

Meal Powder (Mill Dust or Black Powder Meal)
Meal Powder is ball milled Green Mix.
Mill all three ingredients together to integrate well.
I usually add 4-5% Dextrin or 3-4% Gum Arabic to each batch prior to milling as most of the things this powder will be used for will require a binder and its a lot easier now than screening it in later. The binder has little or no effect on performance.
The milling time will depend on the efficiency of the particular mill. 2-3 hours would be considered the minimum with most home style or hobby shop Ball Mills. Rock Tumblers in my experience seem to rotate at a slower speed and are therefore much less efficient and longer mill times will be required
Some ball mill the Sulfur and Charcoal together separately from the Potassium Nitrate for part of the mill time. However all three components must be milled together for proper integration and for best performance of the finished product. As a benchmark all three components should be milled together for at least 30% of the total mill time

Polverone (Granulated BP or Rough Powder)
Polverone is granulated Meal Powder
Wet Meal powder with binder added, usually 4-5% Dextrin or 3-4% Gum Arabic, with a mixture of 75% water and 25% Denatured Alcohol(Metholated Spirit). The alcohol helps break the surface tension and helps to wet the composition better. Take care not to overwet the mixture, when squeezed the mix should clump together but no liquid should come out. If the mix is to wet the screen will block up and not granulte properly,always keep a little dry powder to add in if you overwet the mix. Once you have the mixture clumping it is pushed or rubbed through a screen (8 mesh to 20mesh) a kitchen sieve or window screen mesh will work, screen the mix over paper sheets and leave to dry. When dry you can sort the granules into different sizes using screens or sieves. The wet process involved in granulating the mix allows some of the Nitrate to dissolve and soak into the Charcoal particles for far better intergration and there should be a noticable improvement in the performance of the powder after this step. Finished Polverone can be used as Lift Powder and aslo as Burst Charge for smaller aerial shells up to 2"

Sulfurless Black Powder

Sulfurless Black Powder is made and used in the same way as normal Black Powder but can be used with compositions that contain Chlorate to avoid Chlorate/Sulfur incompatabilities

The most widely used formula for Sulfurless Black Powder is listed below

ChemicalQuantity %
Potassium Nitrate72.73

Star Primes

Star primes are compositions that take fire easily and burn at a hot enough temperature necessary to light stars. Although some types of stars are known to ignite easily even without a prime e.g. black powder and Chlorate based compositions, it is a common commercial practice to prime stars no matter what they are made from.
priming drastically reduces the chance of a star not igniting or getting blown blind. primes are sometimes also used to form a protective barrier between two incompatible chemical compounds such as Sulphur and Chlorate.

Some Hard to Light compositions such as those containing high aluminium percentages may require the use of a high temperature prime

Note: some high temperature primes require an "outer" prime themselves to be lit successfully.

Alongside common Priming compositions many amateurs make use of other priming solutions that involve plain black powder combined with metal additives that make the resulting prime burn hotter. In this manner it is common to see e.g. 5% of finely divided silicon added to hand mixed BP, which will give a cheap but very reliable prime ensuring ignition in almost every case.

A Basic Black Powder / Silicon Prime composition is listed below

ChemicalQuantity %
Potassium Nitrate75
Magnalium 200m+5
Red Gum+5
Silcon Powder+5

Fence Post Prime

Credited to Eugine Yurek
Mill the meal components for 20-30 mins then screen mix in the diatomaceous earth and Silicon. The Diatomaceous earth gives this prime a rough texture when applied and this rough texture increases it's ability to take fire

ChemicalQuantity %
Potassium Nitrate65
Diatomaceous Earth5

Perchlorate Prime

Hot Prime

ChemicalQuantity %
Potassium Perchlorate70
Magnalium 200m20
Red Gum10

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