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Ginning Up Some Cotton

We had a bountiful harvest of cotton here in the land of too-short-a-growing-season-for-cotton! My back 1/40th acre cotton field yielded about 25 pounds of raw, dried cotton bolls (counting seeds and "lint" or fiber, but not husks). This works out to about 800 pounds per acre, which would be a respectable yield if not for the fact that cotton yields are measured by the amount of lint only, not counting seeds. Since the bolls are over half seed by weight, my final yield will be under 400 pounds per acre, which is bad. But, I'm just happy I got any at all, and frankly even this is rather more than I know what to do with.  SO MUCH COTTON!

Here it is being dried on my make-shift forced air drying rack (powered by a large propane-fired greenhouse heater I have left over from a previous life). Hot air comes in the large duct on the bottom left and the plastic wrap forces it to exit from the top, after passing through all the shelves of cotton.

The central problem with American upland cotton (known as short-staple cotton because its fibers are relatively short compared to the longer fibers of Egyptian cotton) is separating the seeds from the fibers.

Cotton fibers grip very firmly to their seeds! Pulling apart cotton bolls by hand and picking out the seeds, I was able, with some practice, so separate about 330 seeds per hour. At that rate this batch would have taken literally months to separate. Fortunately I had previously constructed an entirely transparent cotton gin. Here we see it in front of the job to be done (cat for scale).

Here is the gin in action, separating seeds over 20 times faster than by hand (over 7000 seeds per hour). Apparently in historical times the first cotton gins were about 50 times faster than hand-separating. I think my 20-fold speed up is not bad considering that all parts of my machine, including the circular saw blades, are made of clear acrylic, and I only ever meant it to be used for getting some photos and videos of the process, not to actually gin all the cotton. (I didn't have a plan for that.)

I am using child labor for authenticity.

We're about 2/3 done with the job after about a week of on-and-off ginning operations. One day of production was almost entirely lost to a cat infestation.

Theodore Gray4 Comments