I'll be doing three different methods: 1 will be what seems to be pretty standard and the other two are variations on it. I have purchased 125g of saltpeter (potassium itnrate - KNO3) and the rest of the stuff can be found around the house. Saltpeter is not actually hard to find. It is used in recipes to salt meats, I guess. But that doesn't mean you will find it at a grocery store. I found some at a pharmacy. Just go up to the counter and ask the pharmist (not the store employee, the pharmist). I probably payed too much ($8) for my 125g but it should be fairly cheap.
So I gather everything that I need for this first method:
I poured my self a glass of wine and begin. I don't have a scale because I'm not a drug dealer so I equally divide the saltpeter by volume. I also am doing this indoors because it's winter despite people's warnings.
I pour the 125g into a measuring cup and find it to be 100ml. Therefore the density is about 1.25g/cm3 according to me and that's much different than the value 2.109 g/cm3 given by Wikipedia which probably indicates that it's not very pure potassium nitrate. I don't know what else would be in it but it's worth noting. I split the 100ml into 3 containers.
Next mix in the sugar. There's really a discrepency on the internet. Mostly I read that it's 6 parts saltpeter to 4 parts sugar. But "parts" I always take to mean volume however everyonce and a while I run into people saying things like 60g of saltpeter to 40g of sugar. Now if Wikipedia is wrong and saltpeter isn't 2.109 g/cm3 but is closer to my 1.25g/cm3 and sugar has a density of about 0.7g/cm3 then they are about the same and it doesn't make a difference so I'm going to go with volume.
So that means I need approximately 60ml of sugar (just over 1/4 cup). (People online say not to do more than about 100g per batch since it gets harder and harder to heat evenly.)
So I mix the two together.
As a side note, I'm making the poor man's fuse. So I take some of the saltpeter/sugar mixture and add a touch of warm water, stirring until it's a smooth slurry. Then I throw a bit of paper towel in, take it out and wrap a match in it. Set it aside and let it dry. Tada, the worst fuse ever.
Now I can heat up the saltpeter/sugar mixture. I don't have an old frying pan. I just have 1 frying pan. So I turn the stove on to a very low temperature and put a disposable tin-pie-plate on top of my frying pan which I realize is going to give me less homogeneous heat but I like my frying pan. So that's just the way it's going to be. This is a worry because the sugar is going to carmalize and create a thick mixture which would harden and ruin my one and only frying pan.
So I set the stove on the very lowest temperature and continuously stirred but oh my goodness! When people on the internet tell you this has to be on the very lowest temperature, they mean low like they are talking to 10 year boys who are making smoke bombs (which they probably are) but it isn't really a low temperature. I had to turn it up a bunch of times. For any reasonable person with any experience cooking, this is just a regular low, a low medium.
After about a half hour some yellow started to show. Perhaps the problem was that I was stirring too much. None of the websites said to actually stir it but they said it needed to be evenly heated so I thought it would be a good idea. Only when I didn't stir would parts of the mixture start to brown. Stir perhaps but don't stir continuously.
It really does turn into carmelized mixture. You should be able to get a pretty smooth mixture. Mine didn't start to smoke but it was just beginning to give off fumes.
I took my mixture and split them into 2 smoke bombs by pouring the mixture onto a piece of tinfoil, sticking my homemade fuse into it and then using the tinfoil to wrap it up into a ball. And now they are cooling.
For the second mixture, all the steps are the same but I added a little honey as a liquid fuel. You could alternatively use cornstarch, apparently.
Everything else is the same. Except it seemed to go much faster. Whether that was because it was already at a higher heat or if the honey speeds the process, I don't know.
This method was only found at one place and the guy said it was his own creation so we'll see. For this method, I take two tea lights and I melt them down in the tinplate(actually I melted one and thought it wasn't enough so I melted half of another - so 1 and 1/2 tea lights). Once they were melted, I slowly pour in the saltpeter/sugar mixture and stir it till it's smooth. Pour into tinfoil and add fuse. Done. No carmalizing. I'm worried about these holding together. They're a little bit flakey and not as hard as the others.
And that's our science experiment for the day. Join me tomorrow when I light them and grade the recipes.