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Fuse Me!
By Sparky in July 2002
How to make blackmatch fuse and other fuses
Disclaimer: This is a work of fiction. Under no circumstances should you ever even pretend
to almost think about doing anything in this document.
One of the most important things you need for any pyro project is fuse. Hopefully you will be able to find commercial visco fuse from hobby stores, fireworks shops or pyro suppliers. If you can't however then the best alternative for homemade fuse is blackmatch. This is very simple to make as it is just a cotton string with black powder and dextrin coating on it. The dextrin acts as a binder to hold all the ingredients together. The more dextrin you have in the mix the stronger the fuse will be, and the slower the fuse will burn. If you add too much dextrin the fuse will not sustain combustion. You may omit the dextrin and obtain much weaker and crappier fuse, if for some reason you can't buy or make dextrin. Here is a procedure:
1. Collect all the ingredients and materials: a mixing stick, a container (a small yogurt container is good), meal powder, dextrin (see next step), cotton string, pliers (optional), something to add water with (preferably a spray bottle), a plate of waterproof material with a 1/8" diameter hole in it (or larger hole if you have thicker string), a spoon.
2. To make dextrin (not to be confused with the sugar dextrose which is also called glucose) : spread corn starch (available in any grocery store for use in cooking - you probably already have some) evenly on a shallow pan, and brake up as many lumps as you can. You can supposedly use other starches but I have never tried it. Preheat the oven to 350 degrees Fahrenheit. Leave the corn starch in the oven for around three hours. The corn starch will slowly pyrolyse to dextrin and you will be able to tell from the orangish color. Stir the corn starch about every half our. This smells a bit funky but its not too bad.
3. Make some meal powder (if you don't already have some) by mixing the ingredients for black powder (75% KNO3, 15% charcoal and 10 % sulfur). Using a ball mill to grind the ingredients and incorporate them is preferable, otherwise grind the ingredients as finely as possible with the oxidizer separate. You may mix the charcoal and sulfur together to grind them (a coffee grinder works all right, followed by a mortar and pestle or even a beer bottle and plate of glass). Then mix the oxidizer in, which should also be as fine as possible. You may be able to crush gunpowder that you have bought from the store and replace meal powder with that.
4. Mix in about a maximum of 3/4 teaspoon of dextrin for every tablespoon of meal powder. This is where practice comes in, to know how much dextrin to add. Test the mix by burning a small pile of it before you add the water. The mix's burn rate will slow down significantly when it is applied to the fuse and dried. If the mix burns too slowly, add more meal powder.
5. Once you are satisfied with the mix, add water to it to form a paste. Put the string in the paste and make sure that the string is evenly coated, you may want to rub the slurry into the string with a spoon.
6. As you are removing the string from the container with slurry in it, draw it through the plate of material with the hole in it. This will scrape off access slurry and make sure the fuse doesn't go over a certain diameter. Don't have the hole so small that it scrapes off all of the slurry or your fuse will have nothing to burn.
7. Optional: I haven't experimented with this but it seems to improve the durability of the fuse. Once the fuse has gone through the die (hole) then grap one end with your fingers and the other end with pliers and stretch the string.
8. Tape the string up somewhere to dry, preferably in the sun and of course away from any ignition sources.
9. Repeat steps 5 through 9, until you decide to stop, adding some water each time to the mix as the cotton string absorbs water like a sponge, drying out the slurry.
10. Important: Always test your fuse. If it fails, it could do a number of things including go too fast and set off the device in your face, or it may not burn at all and make all your devices fail. I suggest testing your fuse for burn time as well as bending them and subjecting a test piece to some abuse to see how much physical abuse it can take before it fails. Bending is the most common type of abuse your fuse will suffer.
You should end up with fuse about 1/8" wide preferably. The thicker the fuse, the stronger it will be but you will have to have larger fuse holes of course.
Don't try to coat more than one fuse at a time as they may
tangle and it is very messy to undo string coated in black powder slurry.
Don't let the fuses touch when they are wet because they will stick.
If you added too much dextrin and the fuse will not burn, make a water and meal powder slurry and leave out the dextrin, then repeat the fuse making procedure by using the defective fuse as if it were normal string. You may have to let it soak or rub the string more.
Variations:
To make your fuse waterproof you may want to buy plastic shrink wrap tubing from an electrical supply place. Put the fuse in the tube then heat it with a hair drier to shrink the plastic around the fuse.
Apparently silicone caulking as the binder instead of dextrin makes a good, flexible fuse.
Quickmatch is blackmatch with a wrapping of paper around it. It burns very fast and is used to set of multiple devices at once or used in shells.
Other things you may want to investigate are:
-stickymatch- go look at Dan Williams' page
-Hollow string with black powder slurry injected in it with a syringe -
makeshift visco.
-Coating your fuse with nitrocellulose lacquer
-Touch match
Touch match (or touch paper - not to be confused with flash
paper) is a very simple, slow burning wick I consider it a wick because
it will not burn through a constrictive hole like blackmatch fuse will. I think
touch match gets its name because it is very easy to light, thus you only have
to touch it with a flame. To make touch match make a saturated solution of
potassium nitrate, dip in paper towels, dry them out somewhat by squeezing the
paper, then let them drip dry or just put them on a flat surface, I'm not sure
which is better. When the touch match is dry then cut the paper towel into
strips. Don't cut the paper up first then dip the strips as it is much more work
and unnecessary.
Touch match is also useful for
testing compositions, put the touch match down and some composition on top, then
light the wick.
I have found a hybrid of blackmatch and touch match to be
very useful. Obtain some normal masking tape, cellophane tape or clear plastic
tape, cut a narrow strip of touch match, and a length of blackmatch. Connect the
two matches together by rolling one end of the touch match around the black
match and taping the match in place. Here is a diagram:
Don't wrap the tape tightly or you risk extinguishing the
blackmatch. Make sure the tape does not touch the touch match before it ignites
the blackmatch as the tape will extinguish the touch match. I find these fuses
very useful as they provide a long getaway time, are easy to light, will burn
through a hole, and the touch match can flex without being damaged like
blackmatch - these fuses are more robust during storage and travel.