[MS825]

Found a recipe to make our own clay pigeons. I like the idea and the price is close, but still too much. It is about 80% calcium carbonate and 20% stearic acid (ratios can change depending on how hard it needs to be.) However, the stearic acid is EXPENSIVE.

Just some more info: We are supposed to heat the mixture until it becomes a paste and then mix well. Once a paste, we put it in the mold and wait for it to cool, and we are done. So guess the melting point might be an issue.

Is anyone familiar with a substitute for stearic acid? Hopefully about half the price or less  

[Stepan]

Stearic acid is easy to make. Buy a natural soap bar - the cheaper the better. Dissolve  it in hot water and add any acid (food vinegar will work, but you will need a lot of it). Check for pH it should be <6.  Stearic acid will precipitate as scum. Let it settle, drain excess of liquid, filtrate.  Whatever you collected on the filter is mostly stearic acid. From 100 g of soap you should get around 80 g of Stearic Acid

Before you started, try the reaction on small chunk of soap. If the soap is not natural entire reaction may not work.

[MS825]

let me clarify a bit more. I need about 15 tons to use this recipe for a year. The price tag of about $2100 per ton is the issue.

[Stepan]

  OK, 15T is a different story.

But $2K/ton is cheap. It is $2.1/kg or $1/lb. You cannot buy any chemical for this money. Even shipping from the manufacturer to your shop will cost you about the same or more.

[MS825]

The calcium carbonate is only $70 per ton delivered.

Looks like I might have to keep looking for another recipe as $2100 just wont leave me any room for equipment and labor for running it.

[MS825]

Okay, if not stearic acid... what is the stuff doing. I am in the clay business, I throw clay pigeons, not mess with chemicals. Though it has been a learning curve, still no idea what is happening. A friend gave me this recipe.

It looks like the heat breaks down both elements to a paste to make sure you consistent mixture and can inject it into a machine consistent too.
I am guessing the calcium carbonate is filler and the stearic acid is a bonding agent? So I should be looking for other bonding agents? Or is it the combination of both items very specifically chosen and I cant just replace one item?