September 2016
The Herb Farm

Figs, Poison Ivy, Aluminum and Clay

A few weeks ago, while researching a project, I discovered some interesting facts about one of the key products in a formula of dry minerals.

The research was to find out how to make a pulley for the shaft in my workshop that spins the polishing and buffing wheels.

You may be wondering why I don’t just go out and buy one. It is because the pulley desired isn’t a standard size and the only way to buy one is to have a foundry cast one. Uh. Nope! I visited a foundry in North Birmingham recently and got a quote. The figure was somewhere from $1,200 to $1,500.

The reason I needed an odd-sized pulley is so my medium-density-fiberboard polishing wheel could run at 375 revolutions per minute slower for some knife-sharpening applications.

One of my neighbors suggested, instead of calculating the pulley size, I should buy a motor with a variable speed potentiometer.

I was ready to do that. …

Now, back to the foundry. The folks at the foundry were very nice, helpful and took a couple of hours out of their workday to teach me a little about what they do.

For example, they took me from start to finish and showed me how they got an order for a part and made it, then shipped it out within a few days.

The parts are described by the customer and then the design department used a CAD program to create a workable 3D image. It is then sent to a 3D printer where a polymer prototype is made from a proprietary plastic resin.

Then, depending on the quantity needed, either the item is duplicated on the printer or it is sent to the rubber mold department where the prototype is coated with rubber mold material. Once unmolded, the rubber mold is reinforced with another proprietary material – a resin with some sort of fibers in it. The mold is used to cast several polymer clay duplicates of the part ordered. The dupes are then sent to the casting department.

In that department, wooden frames or flasks are made to receive what is known as greensand. The green sand is composed of 10 percent bentonite clay and 90 percent silica sand. A small amount of water is added. (Actually, they use about a dozen different formulas with assorted ingredients) The sand is not green in color, but is green because it is wet or fresh.

The flasks are divided into two parts: the bottom or drag and the top or cope. A layer of greensand is placed into the drag and rammed tight. The part to be cast is placed on the green sand with half of the part protruding from the frame. Green sand is then pounded around the part and leveled with the top of the drag. Talc is then dusted onto the part and green sand. The cope is placed in position and greensand is rammed into the frame, being careful not to disturb the part in the drag.

The flask parts are separated and the part is then removed. Pour sprues and vent holes are placed into the mold.

This company casts in aluminum and brass. They asked not to be named for obvious reasons.

I won’t go into metal smelting, but molten metal is poured into the molds. After a few minutes, the greensand is pounded out of the flasks, revealing the metal part. The sprue is cut off and the part goes to the finishing department where it is sanded and buffed, sandblasted or milled by a machinist.

The whole experience really got me going.

I began researching small furnaces and green sand formulas and got so wrapped up in the things I was learning that I forgot why I had started the whole research process – the casting of a pulley from aluminum cans smelted in a portable furnace.

… I bought an electric motor with a variable-speed controller.

But, I also bought the components for making greensand, building a small furnace and building some casting flasks. I will begin construction, and hopefully casting, this month.

OK. The interesting facts about the component not mentioned in the first paragraph are about clay. Not just any clay but bentonite and a couple of other types of clay.

Bentonite clay is sometimes mixed with diatomaceous earth that can be purchased in food-grade standards. Bentonite clay or diatomaceous earth is sometimes mixed in chicken feed or other grain-type foods. I have used that for years in my whole-grain storage containers to control insects.

Bentonite is nothing more than cheap cat litter or Oil-Dri. Of course, that depends on where it is mined. If you buy Oil-Dri from the Mississippi plant, it’s usually bentonite clay. However, if your bag states it is from Georgia, it is probably palygorskite. Although they have similar properties for soaking up contaminants, they don’t have the same makeup when it comes to making greensand.

I found a product at a Westwood Auto Parts store that has proven to be even better. Thrifty-Sorb is made up from Montmorillonite clay that makes a better greensand and has one other property that most interested me.

I usually get poison ivy somewhere on my body at least once a year. Last month, while continuing my noxious vine eradication chore, I accidentally fell into a heap of vines that was destined for the landfill. Guess what? I didn’t get it washed off in time and contracted contact dermatitis from poison ivy.

I read that Montmorillonite clay was reported to have been used for contact dermatitis, so I made a poultice out of some mixed with warm water. I applied it to my arms, where most of the redness was, and it stopped my arms from itching. I did the same when I got fig-fuzz irritation while harvesting figs. It worked for me.

Speaking of figs … how about some fig and walnut muffins for tea?




Miss Opie’s Fresh Fig and Walnut Love Muffins are probably the best muffins in the world.

2 cups all-purpose flour
1 teaspoon baking soda
½ teaspoon salt
½ teaspoon cinnamon
1/8 teaspoon nutmeg, grated
2 eggs
1 cup buttermilk
1½ teaspoons vanilla
1 stick unsalted butter, softened
1 cup brown sugar, packed
1 cup walnuts, chopped
2 heaping cups fresh figs, chopped

Preheat oven to 350°. In a medium bowl, combine flour, baking soda, salt, cinnamon and nutmeg. In a small bowl, whisk eggs, buttermilk and vanilla. In a large bowl and using an electric mixer, cream butter and brown sugar thoroughly. Gradually add contents of small and medium bowls to large bowl, alternating while mixing on low speed. Increase speed to medium and stop as soon as they are all combined. Stir in walnuts. Gently stir in figs. Spoon batter into lined muffin tins 2/3 full. Bake for 20-25 minutes or until toothpick test is clean.

Makes about two dozen and they are delicious!


Thursday, Sept. 22, is the Autumnal Equinox! Celebrate fall!

Until next time, remember to watch your salt and sugar, drink plenty of pure water, and breathe in and out!

Thanks for reading!

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As always, check with an expert, like your doctor, before using any herbal remedy.