Bentonite Green Sand Recipe. Sticky, Oily and Just Great!

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Introduction: Bentonite Green Sand Recipe. Sticky, Oily and Just Great!

This is my new green sand mixture. This one consists of 87% of sand and 13% of bentonite clay. And some water of course :) I think in some way it's little better than my last green sand formula which consist brown clay. Bentonite clay is very sticky and oily. It's very different from brown clay. And this time green sand is really green! :)

Step 1: Bentonite Clay

This particular bentonite clay was as hard as a rock! For this green sand recipe we need 13% of clay or in my case 2,2 kg (5 lbs).

Step 2: Adding Water

I couldn't effectively crash it, so I decided to add some water.

Step 3: Sand

The next stage is to add sand. We need 87% of sand. I used 15 kg (33 lbs).

Step 4: Mixing

I couldn't mix clay and sand by hands, so I used a "heavy artillery".

Step 5: After Drying

After a week of drying the result is grate. It works grate for casting.

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    37 Comments

    It is, and also cheaper and easier to obtain. I do a 90% to 10% mixture sand/clay

    Yes, but in my case it was totally free! :)

    Yes, but not always. Cat litter can be made of silica gel, wood or bentonite clay. :)

    Here in the UK our bentonite cat litter is sold as 'clumping' cat litter - i.e. it forms clumps when exposed to moisture. Makes the soiled clay easier to remove from the rest in the litter tray. I have used it in refractory mixes and in green sand - some people try to grind it but if you add enough water it turns to a slurry. Once dried, it can easily be powdered. But I agree, the fine powdered stuff is the best way to go.

    I used such "clumping" cat litter for my cat several years ago but that time I didn't have this hobby (melting and casting). When I started melting this "clumping" cat litter disappeared from the shops. Instead of it they started to sell cat litter made of small wooden pellets :) Several weeks ago I've this bentonite cat litter again but I have enough bentonite now :)

    I have the red clay for sand casting. Can I use this green clay in the same way?

    3 replies

    Hi buddy. I'm sure it will work. :) The only question is the proportion. I would recommend to try from 13 to 30%. If 13% is enough than don't add more. Before bentonite clay I used brown clay: https://www.instructables.com/id/Green-Sand-Formula-How-to-Make-Molding-Sand/
    It worked as well but I had to use 25-30% of clay and sand - the rest!

    Thanks. First time anyone called me buddy.

    You're welcome :) Good luck with green sand!

    You're welcome Gofish! :)

    At first I thought this was a recipie for home made cat litter... You might want to make something other than balls with it for the email thumbnail...

    1 reply

    Hi Captain_Nemo! This is a mixture for making molds and after pouring metals. I didn't add more description because "green sand" is an expression connected to metallurgy, so... :) All my instructables are about metals melting and casting :) I have the other thumbnail and if you click on DuralM you'll see all my instructables and this one with other thumbnail (like for the video in the beginning). Website editors decide what to use as "email thumbnail". It's their decision. I appreciate that they add my instructable to this "email advertisement" no meter with which image! Everybody test green sand making balls from it. It's classic and works good. If you want to see how green sand works during casting, please read/watch my other instructables...

    In fact just several millimeters near the metal burn. I throw away this black burnt layer. Some burnt green sand mix with good green sand but it's not a problem. It won't hold the shape as good as new but it's usually not a problem. :)

    Commonly found at any pottery supply as well…price depends on quantity, 3$ 1lb lot—.65$ 50lbs

    3 replies

    Thanks. :) That's useful information. It should be much more clean than mine.

    May not be 'green' anymore :(