From: jrkitchi@eos.ncsu.edu (JOHN ROBERT KITCHIN)
Subject: Re: Smoke bomb
Originator: jrkitchi@c00029-118dan.eos.ncsu.edu
Reply-To: jrkitchi@eos.ncsu.edu (JOHN ROBERT KITCHIN)
Organization: North Carolina State University, Project Eos
Date: Wed, 30 Sep 1992 00:01:40 GMT


Probably the easiest, although not necessarily most effective, is to mix 
common table sugar with an equal amount of KNO3, it cn be used in its powder form
or it can be melted together by careful heating, or a binder such as dextrin
can be used.

the next section is from another computer board (rec.pyrotechnics):

Preparation of dextrin:

Spread some flour or potato starch on a plate and heat at 220 oC in an oven
for 15...30 minutes. Avoid overheating - when the product is brownish and
readily soluble in water, it's ready. Dextrin can be used either as a mere
fuel or also as a binder. Water is used as a solvent in this case. Sometimes
dextrin is mixed dry with the other ingredients and water is added
afterwards. However, see instructions below for a safer alternative.

The stars are normally prepared as follows (this is probably the safest
method):

1. Dissolve the binder in the solvent used (usually water or ethanol). Pour
the solution into a flat plastic bowl and mix in the other ingredients.
Make sure all the ingredients are thoroughly moistened before adding the
next one. This will almost entirely exclude any accidental friction between
the fuels and the oxidisers. You can use glass or stainless steel tools for
mixing. Grind all the ingredients _separately_ in a mortar before weighing
and mixing them.

2. After you've arrived in a more or less homogenous mix, allow the excess of
the solvent to evaporate (care! do not allow the mix to become too dry, since
you'll have to moisten it again!) and press the mass into a flat cake, about
8 mm thick. With a pizza cutter, cut the cake into cubes 8 mm each side.
A knife or a ruler may also be used. Best results are achieved by keeping the cu
tter clean. Allow the mass to dry (in a safe place; you may use a fridge
fan to aid in drying) and remove the stars by bending and twisting the bowl. Thi
s is why we used plastic. However, see note on using PVC above.
3. Sometimes it is necessary to coat the stars with an igniting composition.
This can be done by moistening the stars with a suitable solvent in a bowl
and sprinkling the igniting composition on the stars. Give the stars a good
shake before adding more solvent or powder. It is advisable to mix
a little binder into the igniting composition before using it for coating.
For example, if you're going to coat the stars with black powder, you should
add some (say, 5%) dextrin to the black powder and moisten the stars with
water. Do not use _too much_ solvent - the stars will stick into each other,
and you'll get only large lumps! Use a dropper for adding the solvent.

You can mix your own powder for coating. It isn't actually true black powder,
not even "meal powder" (mixed and ball-milled powder), but it serves this
purpose well.

75 parts of fine, sieved potassium nitrate
10 parts of fine sulfur (preferably flour)
15 parts of fine, sieved charcoal

This mix can be stored in small plastic containers.

Specific procedures are described below if they are needed. The above
procedure is usually appropriate.





1. Blue smoke

40 parts of copper phtalocyanine (Phtalo Blue)
25 parts of lactose (milk sugar)
33 parts of potassium chlorate
2 parts of dextrin (a water-soluble binder)

Add water and proceed as above. Coat the stars with black powder/dextrin
or a simple ignition composition consisting of

4 parts of potassium chlorate
1 part of sucrose (cane sugar)
1 part of dextrin

This time you'll have to mix the chemicals in a dry state, ie, as plain
powders. Use a small plastic bowl and a glass rod for mixing. Do not grind.
Do not store the composition. Sprinkle it on the moistened stars. Use at
least 20% of the weight of the stars.



2. Yellow smoke

43 parts of quinoline yellow (quinophtalone yellow, Chinolingelb)
24 parts of potassium chlorate
16 parts of lactose
6 parts of sodium hydrogen carbonate (sodium bicarbonate)
2 parts of dextrin (as a binder)

Add water, proceed as above. Like the blue smoke stars, these stars should
be coated either with black powder or the igniting composition described
above.


3. Red smoke

40 parts of Rhodamine B (C.I. Basic Violet 10, C.I. 45170)
24 parts of potassium chlorate
16 parts of lactose
4 parts of sodium hydrogen carbonate
2 parts of dextrin

Add water and proceed as usual. Coat the stars as above.


Many other organic pigments and dyes can be used in coloured smokes.
The dyes should volatilise (sublime) readily between about 300...450
degrees oC, which excludes almost all dyes containing -NO2 (nitro) or -SO3H
(sulfonic acid) groups. Unfortunately, the leftovers are usually the
malicious azo or anthraquinone dyes, with known toxic properties. The dyes
suggested here are all safer than them.

If you wish to develop your own formula for a dye you think should work,
just substitute the dye with Rhodamine B in the previous formula. Every
dye would require a formula of its own, but the third formula is a good
starting point. If the dye you're using is evaporates near or slightly
above 300 oC, use a) 45 parts of the dye instead of 40 parts and b) 8
parts of sodium hydrogen carbonate instead of 4 parts.


credit for above selection goes to:

--
 ___. .'*''.*        Petri Pihko    kem-pmp@          Mathematics is the Truth.
!___.'* '.'*' ' .    Pihatie 15 C    finou.oulu.fi    Physics is the Rule of
       ' *' .* '*    SF-90650 OULU  kempmp@           the Game.
          *'  *  .*  FINLAND         phoenix.oulu.fi  -> Chemistry is The Game.


-John