I've gathered up some common household ingredients,
and a frying pan, because today we're doing some
kitchen chemistry. This is the type of cooking that
gets me excited because I'm trying out recipes for
solid-state rocket fuel.
To get started, I'm taking this portable electric
burner outside and away from anything flammable. I'll
add a frying pan, and set the heat to medium-low.
This lid should help it heat faster, and while that's
warming up, I'll place one of these plastic cups on a
digital scale and turn it on. When the scale has
zeroed out the weight of the cup, I'm ready to measure
portions of these two ingredients. The black bottle
is a stump remover from the garden section of a local
hardware store, and I'm using it because it contains
Potassium Nitrate. And according to the MSDS, it
contains a lot of it. The second ingredient is plain
white table sugar and I couldn't resist a little taste
before investing it into this experiment. Ok, this
recipe calls for a 60/40 mix by weight, and I'm going
to make a 100 gram batch, so I'm adding 60 grams of
stump remover first, followed by 40 grams of
granulated white sugar. That looks good there, so I'll
give the cup a little shake to mix the two together, and
then try to pour it neatly and evenly into the pre-
heated pan. Over the course of about 5 minutes, I'll
need to stir the mix up a little so it doesn't burn on
the bottom. Not much seems to be happening yet, but
after about 8 minutes I can see some of the sugar
starting to caramelize into a liquid. At this point
I'll need to be stirring and mixing a little more
frequently, and as I do, the mixture begins to liquify
and clump together, turning a golden brown. Just a
couple of minutes later, the entire batch looks like
cookie dough, and the white powder is completely mixed
in. I'll need some sort of container to hold this in,
and I'm thinking these Mega Block Legos might work.
At this point, the mixture is just runny enough that
it can be coaxed into the container. It takes about
60 grams to fill this red block, and when I've cooked
up a little more, I'll add that to the blue one. It's
darker in color because it cooked longer, and
generally speaking, I think the less it is cooked, the
better. There's just a little bit left over, and it's
hot, but if I'm careful, I can roll it into a test
piece for measuring the burn rate later on. Alright,
while those are cooling, I've got one we can light off
just to see how it looks. I'll get it started with a
propane torch, and when the fuel catches, it throws
off a nice little flame, and quite a bit of smoke.
This mix is 4 months old and seems to burn a little
slow, but it's still a good show. And you can tell by
the melting plastic that it does get pretty hot. Ok I
just made 3 more batches of fuel that are all a little
different. To the yellow one I added 30 grams of
water and then turned the heat up to boil the water
out. After a couple of minutes, the mix turned to a
white mush and was ready when all the water seemed to
have cooked out. This method prevented the sugar from
caramelizing, but was a little crumbly when dry.
I packed that into this yellow LEGO block and set it
aside. Another batch was made using a mix of 58%
Stump Remover, 29% Sugar, and this time I used 13%
Corn syrup, and 30mL water. The water was cooked out
the same way as the last, and then about 1 gram of
homemade rust powder was added, and stirred in
throughly. When it was ready, it looked like a creamy
chocolate frosting, and I packed that into the green
LEGO. I may have accidentally trapped an air bubble
inside. You'll see this explode later when we test
it. For my last batch, I sprinkled some red rust into
the mix while it was still wet, and like the others,
stirred it until the water had evaporated out. This
mix kind of looked like a delicious red velvet cake,
but I wouldn't recommend eating it. I took samples
from each fuel, and measured them all to a length of
1", then timed the burn rates to see how they
performed against each other. I was happiest with the
batch made with my homemade rust because it burned the fastest.
I had a few sample scraps left over that
were begging to be burned up, so I did that. And now
here we are with 5 samples ready for ignition.
Testing the red one, I'm really impressed at how fast
it ignites and burns, but a little nervous when it
starts spinning out of control. I'm out of there.
The blue one lights off just as powerfully, and builds
thrust to the point to where it takes off, leaving me
in a total whiteout. This yellow one was the un-
caramelized version and I got smarter this time by
pointing it down to prevent it from taking off like
the others. It burned slower than the first two, but
the amount of smoke it put off was still incredible!
Ok so this green one has the rust in it, and it lit up
instantly and then blew up. But did you notice how
much faster the burn rate was? That's amazing. For the black
one I decided it was a good idea to hold it in place
with another cement brick, and that strategy seemed to
work. At least this time I didn't get sprayed in the
face with spewing hot rocket fuel. Overall I think
I'm happiest with these mixtures using the rust. With
a different homemade casing that actually has a
nozzle, I was able to get a successful rocket launch
that I think went a couple thousand feet high.
Well that's it for this project. If you like these videos,
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I appreciate your support. Thanks for watching.