So in 1999 a movie was made of the book Fight Club. The premise of the movie (according to IMBD.com) is that “An insomniac office worker looking for a way to change his life crosses paths with a devil-may-care soap maker and they form an underground fight club that evolves into something much, much more...”
The soapmaking part is an intriguing social and economic statement about modern life. The premise is that they steal fat that has been liposuctioned from people, turn it into soap, and then sell it back to those same rich people through high end retail Macy’s –like stores. Essentially people pay to get rid of their fat, and then pay again to obtain it again. I personally like the macabre, almost Sweeney Todd-like references (and now that I think of it Helena Bonham Carter is in both movies). And if that isn’t enough the glycerin they siphon off of the soapmaking process is also used to build bombs.
So although this movie came out almost 15 yrs ago, I will have one person (usually a guy) ask me if I have ever seen the movie. I say yes and then explain this (in a shorter more compact way than I am explaining it now)…
According to the American Council on Exercise the average obese woman is 32% body fat, however the human body needs about 12% fat for daily living, so let us just assume that 20% of the overall weight could even be extracted.
Thus, if you are a middle aged woman who weighs 200 lbs, 40lbs is fat. Now the fat needs to be rendered to remove it’s water before it is made into soap.
According to Dr. Jeffrey Utz, Neuroscience, pediatrics, Allegheny University, different people have different percentages of their bodies made up of water. In adult women, fat makes up more of the body than men, so they have about 55% of their bodies made of water.
So 40 lbs of fat minus 55% water = 18 lbs of rendered fat to make soap with. Assuming a 6 oz bar of soap, that leaves you with just 48 bars from the average human obese woman who has had ALL of her excess fat extracted through liposuction. And if I remember the movie correctly, the bags they steal certainly don’t seem very heavy or numerous for that matter.
Seems like a lot of work for a soapmaker so professional they can sell to the big box stores!
And for the bomb thing? According to soapmaker Kailer Westerman: In the simplest terms: you make soap out of fats and lye. The fats already contain glycerin as part of their chemical makeup (both animal and vegetable fats contain from 7% - 13% glycerine). When the fats and lye interact, soap is formed, and the glycerin is left out as a "byproduct". But, while it's chemically separate, it's still blended into the soap mix. While a cold process soapmaker would simply pour into the molds at this stage, a commercial soapmaker will add salt. The salt causes the soap to curdle and float to the top. After skimming off the soap, they are left with glycerin. They then separate the glycerin out by distilling it. (if you are keeping up with the math this is about 2 lbs of glycerin for every 40 lbs of fat they started with.
Now glycerine itself is very stable and even good for you, nitroglycerine is commonly produced by treating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. It is dangerously sensitive and dropping or bumping a container may cause it to explode. This is the bombs are made of. This isn’t explained in the movie at all from what I recall and they use quite a few large barrels of this stuff.
I am pretty good with chemistry, and this is waaaaayy beyond me. So this is my personal myth busting of the movie. I haven’t read the book, it may explain more, but the movie was too violent for me the first time and I have been told the book is worse, so I will skip it.