Southern Fried Propellant
Electric Skillet Rcandy

Last year, Teresa went to present her research at the Florida Entomological Society conference in Ft. Lauderdale.  Yes, we live in Florida, but it is a LONG state.  Ft. Laud. is a good five hour drive from here, and I had to work that day.  We drove down after work and checked into a bed-and-bathroom.  

So it was nearly 10pm. before we hit the street looking for dinner.  Now urban hunter-gatherers, we stalked our Oldsmobile up the beachside drive, looking for sustenance.  Everything still open was a loud bar or a glitzy fast-food.   We drove on.  Finally found a restaurant open until midnight, named "The Black Orchid."  It was black.  It looked like a dive - just my kind of place.  I was surprised there were no Harley's parked in the lot.  Opening the door, we were greeted by a very proper and well-dressed host, who looked at me.  Good thing I was wearing my best blue jeans.  It was nearly empty.  I am sure that's the only reason the host let me past the door.  The only visible souls were four well-dressed waiters with towels over their arms.  I had never seen such a sight except in old movies.  They looked at us like we were the meal.  "Expensive," I said.  Softly.  

Sometimes I like to be wrong, and this would have been a good time.  But no, the place was not diveish at all.  It was a pretentious but very nice restaurant.  And like most good restaurants, it was worth it.  The food was excellent.  We gained a new appreciation for Alfredo sauce.  I had tried to make it before from cookbooks, but never quite got it right.  Back home, I tried to replicate it and found the best approximation to be equal volumes of butter, cream, and Parmesan cheese with a touch of black pepper and nutmeg.  No doubt this is why, a few months later, my doctor gave me the sad news every middle-aged man dreads:  "high cholesterol."

But after dinner, Teresa realized that she had left her belt at home.  It was needed to complete her suit at the presentation.  I offered mine.  She laughed.  I set the low end of the fashion standard, and have little competition there.

So the next day we went shopping.  After last night's $150. dinner, I was in a frugal mood.  

This time we went South.  Driving past miles of fancy hotels, restaurants, condos and tiki bars, we finally arrived at Davie, a more "normal" little town.  Spotted a thrift shop with some trash in the parking lot.  A good sign.  Inside, under a table of rumpled tee-shirts, there was a banana box of previously-owned belts.  As Teresa riffled through them, I glanced around.  This place had some real stuff, cheap.  A sucker for cookware, I found two small Revereware pots, the old style with the scrolled handle, for $5. each.  There were some cute glasses and coffee mugs, four for a dollar.  Greedily filling my arms, I dropped a glass.  It broke loudly.  The proprietor yelled:  "That one's ten dollars!"  He was a card.  I bought the shards for a quarter.

But the treasure of the day was a Farberware stainless-steel electric fry pan for $10.  It had no lid, but looked to be in good shape.  I picked it up.

Back at the hotel, I found that it boiled coffee-water just fine.  Back home, it made a pancake or two then sat around the house for a year with nothing to do.  Fact is that I have little use for an electric skillet.  The kitchen stove is more convenient, and works very well.

A couple of weeks ago, I started thinking about Dan Pollino's method of making propellant in an electric wok.  And Rick Creamer and Steve Ghioto mentioned they had made propellant in an electric fry-pan, so maybe my Farberware had a use after all.  It is stainless, so I don't have to worry about the KNO3 reacting with the aluminum, right?

I tested a few batches, and after a few marginal failures and inexplicable successes, arrived at a procedure that works reliably.

The skillet is a nominal 10-1/2 inches diameter, but measures barely 10 inches across the top, inside diameter.  

Two methods emerged.  One makes a small batch of propellant very quickly, the other makes a larger batch but takes much longer.

Quick method:  

50g KNO3
25g sucrose
12g Karo Syrup
35 ml water

This mix is poured into the skilled, and temperature set to 300 degrees (F).  It is brought to a boil and stirred until all solids are dissolved.  Then it is allowed to cook undisturbed for about 10 minutes, until the propellant begins to color over the heater element.  At that point, the temperature is reduced to 250 degrees and the mix allowed to heat for another 15 minutes until it is a light brown color all over.  

At this point, a wooden spatula is used to scrape up the flakes, which are then pressed and kneaded into a coherent mass.  It is quite possible to get the propellant too dry with the electric skillet, but that problem is easily solved - just add a little water.

Slow method:

100g KNO3
50g sucrose
25g corn syrup
50ml water

Essentially the same, but it will take the propellant about two hours to dry properly.  It will brown a bit during the process, so that the resulting propellant may burn more slowly than light propellant.  That is OK for larger motors.  If this is to be used for small motors, like model-rocket motors, then 1% red iron oxide might be added, just knead it in.  

Here I have weighed out a colorful little bowl, added 50 grams KNO3, 25 grams sugar, and 12 grams Karo syrup.  I am in the process of pouring 50g water, which should be 50ml, right?  Right.

The electric skillet is out on the porch table.  It's really the top of an old stove that served kitchen duty for 15 years or so, until it got promoted to porch duty.  It is non-functional now, but is holding up this section of countertop rather nicely.  

The burner ring is here.  Photo so you know why the propellant makes a brown ring there as it cooks.

Wet stuff is scraped into the pan

Temperature is set at 300 degrees F

Big chunks are broken up with spatula

Little chunks are broken up with spatula.

Bubbles are broken up with spatula.  Now this is getting crazy.  I like those bubbles.  Leave them alone!

Mix is allowed to cook until bubbles stop forming and become solid.  

The bubbling has ceased, most of the water is gone, but not all of it.  The surface is now damp but solid.  Since the water is being heated underneath, the surface is beginning to pop, throwing little flakes of propellant around the pan and sometimes out of it.  Drastic action is required to keep most of the propellant in the pan.


First, the temperature is reduced to 250 degrees F.    This is all that is really required, as there is no popping and spattering at this lower temperature.

It will finish drying at this temperature, which does not degrade the propellant quickly.

Next, it is covered with a "spatter guard."  We use these here in Florida to keep the bugs out of the collard greens.  Also recommended when frying bacon in the nude.  (Apologies for any disturbing images that might have occurred in relation to that comment.  Please envision the supermodel of your choice, not me.)

After an hour, the propellant seems dryish, and has turned brownish over the heating element ring.  Time for a test!

A small amount is removed from mid-pan, cooled for a few seconds, and rolled into a ball.

Or at least attempted...  This stuff is too dry.  The flakes do not want to adhere to one another.  It needs water!

Water is supplied in the form of Karo Syrup, just a drop or two.  It is easy to overdo this, so I pour carefully.  About 1/4 teaspoon was added, maybe a little more.

The temperature is increased to 300 degrees for about 3 minutes, to get the flakes good and hot.  It may darken a tad during this heating, that's OK.  

A wooden spatula is used to scrape up the flakes and mix in the recently-added Karo Syrup evenly.

The flakes are pressed with the back of the spatula to mash them together.  A good bit of mashing and kneading is required to get this propellant to its proper texture.  (For large oven batches I use a food-processor.  Small batches like these are easily done by hand.)

If it refuses to stick to itself, there are two solutions:  heat and moisture.

Try heat first.  Let it heat back up for a minute or two, and try kneading again.

If that doesn't work, add another drop or two of water or Karo, and knead.

Finally, it is all consolidated into a ball.  It should have a texture  resembling modeling clay, or perhaps a little "creamier" at this temperature.  

Flatten the propellant wad by chopping at it with the spatula.  This will spread it out so that it contacts the pan better.  That way it will reheat much faster and more evenly.

Reduce the temperature to 200 degrees F.  Let the propellant cool for perhaps 10 minutes, and test it for texture.  

If it is stiff and crumbly at 200 degrees, it needs more moisture.  So heat it up until soft, add a few drops of Karo or water, and knead again.

Notice how the propellant mass is a different shape each time?  If I were Betty Crocker, I might employ a "food stylist" to get more uniform photos.  But every time I knead this mass, it changes shape, right?  So please do not be disturbed by the multiplicity of forms this propellant takes from photo to photo, it's moldability is one of its charms.

So now I think I have it right.  It is pliable at 200 degrees, although still a little bit stiff.  The snap test may be irrelevant, but I will try it anyway.

This time, it rolls into a ball rather nicely.

And it is easily mashed into a disc.  

After a minute's rest on this cool, dry plate, I bend it to see if it flexes or breaks.

It breaks!  Snap test is passed!  This batch will become rock-hard when cooled.  In fact, it could stand to have another drop or two of moisture, but that's OK - it will work.

Click Here for a video of a snap test (925k .wmv file, 8 seconds of uninspiring video)

Next test:  Burn rate at 1 atmosphere.  This is more to determine the ignitability of the propellant than anything else, as the burn rate will be accelerated dramatically when burning at high pressure in the motor.

A gram or so is taken from the pan and rolled into a little stick exactly 1 inch long and about 1/4 inch diameter.  

It is easier to roll these little sticks on a cloth-covered surface, such as a firm mouse pad.  I have a little board covered with denim for this purpose.... somewhere.  Guess I should find it.  Or make another one.  It is just a cut-off jeans leg with a piece of 1x6 pine stuck in it.  Works great.  

The strand is laid on a metal pan and ignited with a torch.  Usually, I use a stopwatch to time the burn, but since this one is being caught on video I didn't bother.  

The burn is timed from the instant of ignition to the instant of burnout.  This strand burned for 12 seconds, indicating good ignitability.  Click Here for a video of this burn test. (1 meg .wmv file, 14 seconds of fire and smoke.)

Faster-burning rcandy is easier to ignite.  Slow-burning propellant burns just fine once the case comes up to pressure, but it takes a little longer for it to get there.

But slower burning rcandy is a little slower burning in a motor too.  Tthe difference is reduced when it burns under pressure, but it is still there.  
Putting it away

All good things must come to an end.  And on weeknights, they come to an end all too soon.  I have a full schedule in the morning so I can't do any more wacky experiments, so I must put the propellant away.  Fortunately, I have a fun technique for doing so.

Mold liner is made by sticking wide plastic mailing tape onto a sheet of copy paper.  Clear plastic tape works fine too, but the brown stuff is easier to see in these photos.  Cooled propellat will not adhere to this plastic.  This allows the cooled propellant to be removed from the mold.  Later, it can be removed from the liner without a struggle.  

You can barely see the mold.  It's a section of PVC tubing, 3/4 inch diameter and about 5-inches long, just big enough to hold this small batch of propellant.  

To get the right length of mold liner, I roll it around the outside of the tube, and cut it off just a bit short.  That way it will encircle the inside with a little overlap.

The taped paper is rolled up and inserted into the PVC tube.  

Sometimes it is hard to roll this taped paper up without creasing it.  I often use a smaller dowel as a form to roll it around, which makes it easy to insert.

I chop off a chunk of warm, soft propellant, roll it into a stubby snake, and drop it into the lined tube.

A dowel is used to press it down, making room for the next stubby snake.  

This is repeated until the propellant is all in the tube or the tube is full, whichever comes first.

For long-term storage, I find the aluminum-foil duct tape an ideal sealer.  

Here I cut a section about three inches longer than the propellant slug, which is now cool and has been removed from the PVC mold.  

Note that the taped-paper liner is stays on the propellant.  That will make it much easier to unpack later on, as well as giving it a bit more moisture barrier.

The backing is peeled off the tape, and the propellant slug rolled up inside it.  Then the open tape ends are mashed flat and rolled over to seal out air.  

Packages like this can keep indefinately.  

I make a point of  labeling each package immediately.  Of course I know what it is now.  But give me 15 minutes, and some doubt will creep in.  Give me a week and I will not have a clue.  Labels and records are a fine form of external memory.  Masking tape makes a good label.

Problem:  Dry, crumbly, does not adhere to itself

The cause:  Cooked too dry.  Not a big problem, easily remedied.  

Solution:  Reheat to 250 degrees, add a little water or corn syrup, just a few drops.  Knead thoroughly.  Repeat as necessary.

Problem:  Turns brown on one side while cooking, the other side stays wet.

The cause:  Tilted pan or oven.  

Solution:  level the oven or the pan so that the initial solution is an even depth at all points.