Smoke bomb SOP
Ingredients (for one bomb)
30g Potassium nitrate
20g Dextrose
Wicking (optional)
Materials
Scales
Weighing tub
2 spoons
Pan with high sides
Heat source
1. Measure out 3 parts potassium nitrate and 2 parts dextrose.
Add to saucepan, and make sure there are no lumps.
Always measure by weight, never by volume.
2. Make sure the lid for the potassium nitrate is on and has
been put away. A stray spark landing in a bulk container of
oxidizer can ruin your day.
3. Turn the stove on to the lowest temperature possible.
4. Put the pan on and stir every 5-10 seconds. As the mixture
heats, the dextrose will gradually melt, sticking the mixture
together.
If the dextrose starts turning brown, or you start getting
bubbles forming it’s too hot/you’re not stirring it enough.
5. Once it is the consistency of smooth peanut butter, turn off
the stove, and take it out to cool. Use spoons to divide it
into the portions you want. You can use a mold, or just
chuck it on a tray in a lump. Using a mold is recommended
as it increases the shelflife and burn time.
Don’t handle with your hands – it will be hot like molten
sugar, take it’s sweet time cooling down, and be sticky.
The best of all combinations to burn yourself.
6. Clean your equipment – this recipe is quite water soluble,
so it makes this easy.
7. Leave for a few hours to cure before igniting. This mixture
is hygroscobic, so if storing for a long period, the mixture
might need to be gently dried before use. Store sealed in a
cool place.
Be aware that if the sealed container heats up enough to
ignite the smoke bomb, you’ll effectively have a badly
made pipe bomb.
8. You can ignite it with an open flame, but depending on the
surface area of the part you want to light, this can take some
time. Do not ignite it where it can ignite other objects. Do
not handle once lit.
Variations/Notes
- Other sugars can be substituted for dextrose. In this case
they may caramelize a bit when cooking but don’t over do
it. You really just want it to melt so that the ingredients are
closely touching each other.
- If the reaction speed is too great you can add baking soda or
dyes to the mix to slow down the reaction, between 1-5
parts.
- Adding Paraffin wax has been reported to increase the
smoke yield.
- Be wary of smoke bomb mixes that include potassium
nitrate, charcoal, and sulfur – it’s just a bad recipe for black
powder.
- Most colored smoke bombs use potassium chlorate as the
oxidizer instead of potassium nitrate. You can still color
nitrate based smoke bombs it’s just harder.
- Colored smoke is often not safe to breath in – i.e. the
colorant is carcinogenic, or just plain nasty. Blues made
from indigo or methylene blue seem to be an exception.
- Be aware of ignition sources and when they are on and off.
It’s a bad look to accidentally set off the bombs when they
are being made.
- Wicks aid in the lighting process. They can be made by
rolling string in the molten smoke bomb mixture then
setting aside to dry. Cut to length, then insert into freshly
made semimolten bombs. These fuses can be waterproofed
by coating with nail polish that contains
nitrocellulose/nitrated cellulose as the filming agent.
- When heating a pyrotechnic mixture never put your face
directly over the vessel (i.e. from the perspective of the
above photos). If it cooks off prematurely, your eyeballs
will thank you.
Videos (found in RnD>SOPs>Smoke bomb folder)
Video (50g Blob smoke bomb) is 50 grams
30g Potassium nitrate
20g Dextrose
Video (250g test, 250 test m) is 250 grams
50 grams Sodium bicarbonate
120 grams Potassium nitrate
80 grams Dextrose
Video (300g test, 300 test m) is 300 grams
100 grams Sodium bicarbonate
120 grams Potassium nitrate
80 grams Dextrose