CIA method

From PyroGuide

The CIA method or precipitation method, is a well-known practice of manufacturing charcoal based, black powder type compositions, by allowing the potassium nitrate to crystallize itself out from it's hot saturated solution to a mixture of charcoal and sulphur, with an aid of cooled absolute ethyl- or isopropyl alcohol.

The heating and mixing must be conducted outside. With all the possible safety measures taken :

• 1) Ball mill only the fuel components togheter, namely charcoal and sulphur. The main advantage of the method is, that no fuel and oxidizer does not need to be milled togheter. In fact, the oxidizer does not need to be ball milled at all.

• 2) Prepare a saturated solution of potassium nitrate. To every 1 parts of water, 2 parts of potassium nitrate is dissolved. The solution is heated on a thermostat controlled hotplate to 100'C, and some more water is added as required, to allow the whole of potassium nitrate to dissolve. Do not use open fire or uncontrolled plate!

• 3) Mix the pre-milled fuel components with the saturated potassium nitrate solution. The mixture needs to be mixed constantly to allow for the wetting of the fuel. Eventually, the fuel mixture will suck up the potassium nitrate solution. Beware of the dry zones and be ready to add tiny amounts of boiling water, in case the mixture seems to be getting too thick.

• 4) After the fuel is completely wetted, pour the boiling contents to an amount of alcohol in a separate vessel. Advisable amount of alcohol, is 1 part of alcohol for every 2 parts of weight of the dry ingredients. The alcohol must be pre-cooled as cool as possible, in a freezer.

• 5) Mix as vigorously as possible. Alcohol evaporating the solution helps to cool it down, which effects potassium nitrate salting out into the fuel mixture. Be sure not to have any naked flame sources around!

• 6) Cool the whole mass down to 0'C in a freezer and filter the mass through an old linen cloth. Squeeze the cloth to remove most of the alcohol as best as you can. Discard the black solution or redistill it to 96,5 proof alcohol, if you have a decent reflux column.

• 7) Proceed as with normal black powder. Remember to work safe!

The method can be implemented to various nitrate+charcoal comps, for example Bleser's blonde streamer. After the last step - the ethanol was not allowed to evaporate, Ferrotitanium and binder was added and mixed constantly, until the solvent had evaporated showing the solvent content of approx.10% at the weighting. Half of the dextrin binder in the original recipe was replaced with red gum. The mixture pressed well, and the burning characteristics proved to be better compared with bare dry mixing.

Video of the process [url=http://www.pyrotube.com/play.php?vid=302[/url]]