Clay Help!! Sodium Bentonite - New Zealand

[jes2xu]

Hi all,

I am having a super hard time finding powdered clay that will be suitable for homebrew. Im in New Zealand, if there is anyone here that has a solution please let me know!

I have however found bags of sodium bentonite for $25 for 25kg.

Im a little weary of it due to its shrinkage. Is this a problem in small amounts in homebrew?


I have been looking for the following, any other key words I could use would be helpfull
builders clay
Bricklayers clay
fireclay
powdered clay
clay dust

[david s]

Hi all,

I am having a super hard time finding powdered clay that will be suitable for homebrew. Im in New Zealand, if there is anyone here that has a solution please let me know!

I have however found bags of sodium bentonite for $25 for 25kg.

Im a little weary of it due to its shrinkage. Is this a problem in small amounts in homebrew?


I have been looking for the following, any other key words I could use would be helpfull
builders clay
Bricklayers clay
fireclay
powdered clay
clay dust

I use a Cement Australia product called "Clay for rendering and bricklaying"If you chase "fireclay" in Australia or NZ you may end up getting a potters fireclay which is designed to withstand extreme temperature, more than twice the temperatures we fire to. It is also far more expensive so go with the builders clay. Skip the bentonite, as you say its shrinkage is high.

[jes2xu]

Thanks Dave,

Yeah you tiped me off some time ago to "bricklayers clay". But I cant find the stuff anywhere in NZ. Have tried all the big hardware stores. Have tried as many industry suppliers as I can, they all want to sell me "mortar". They all have ready made products.

I dont trust the cheap stuff, and cant afford the real stuff.

What does the clay do for us in the homebrew? Is it just a plasticiser? If so can I do without? Or substitute for something else?

[Gulf]

I don't know of anything that can be substituted for the clay in the homebrew. And,I don't know anything about New Zealand's soil. But, natural clay can be found most any place in the world. Try looking at construction sites or new road construction. Here, it is only a few feet down to some very clean clay. It runs in veins. Sometimes, only a few inches thick.

[david s]

You can dig your own clay, but you will have to dry and pulverise it, then sift out rocks and impurities before adding it to any mix. Clay makes any mixture more refractory (fireproof) It will also improve the workability making any mix more sticky, but too much increases shrinkage which becomes a problem.

[jes2xu]

Thanks guys,

I had initially thought of digging my own clay. But decided against it as I was warned about the amount of work it would take.

I decided not to do it as it would slow down the build (drying etc) but now I am still looking for the stuff and could have just started digging weeks ago haha. So perhaps its time to just do that!

Thoughts on crushed pumice instead of clay?

Thanks again

[david s]

Try potters suppliers, they usually stock powdered clays for making slip bodies. Ask for a powdered earthenware clay, it should be cheaper. Crushed pumice would be good for an insulating mix, but not for a dense mix or mortar.

[JRPizza]

I don't know of anything that can be substituted for the clay in the homebrew.

Joe, didn't you and others use some of their residue from cutting bricks as a fireclay substitute in homebrew?

[Gulf]

Joe, didn't you and others use some of their residue from cutting bricks as a fireclay substitute in homebrew?

John,

Yes, I and several others have. I did not mention it because a wet saw with a water reservoir is critical to reclaiming the brick dust. And, it is not actually fire clay. But, I'm told that is close enough. I reclaimed mine from the settlings in my wet saw's reservoir. Once dried, I sifted it through an old window screen. Sieving it this way will yield a powder. However, some particles are about the same size as fine sand. I compensated by substituting a part of sand with another part of clay in the formula. I only tried to fit the inside joints of my build tightly. The outside joints were very large. I think that the large particles in the reclaimed clay are actually better for filling those spaces without shrinkage. To have enough reclaimed clay to get started, it would be best to cut the floor brick and the first row of dome brick. After that, there should be enough clay produced from the resevoir to stay ahead of the build. This is probably not what most builders do, but I only set my dome brick in place. I came back later and tuck pointed the large exterior gaps.

[jes2xu]

Hmmmm interesting.

Unfortunately I am "cutting" my bricks with a diamond blade on a grinder and a hammer and chisel. I was planning on using some of the off cuts though. breaking them down a bit and filling the larger gaps.

I called the local potter who has no powdered clay.

Guess I am digging the stuff

[Gulf]

I ran across a link some time back that I thought was very interesting. Practical Primitive shows a step by step "Water Extraction" method to remove the sediment. He is processing for pottery and only wants it to dry just enough for forming. I would imagine that after processing, it could be rolled out like dumplings to dry faster .

[Toomulla]

Hmmmm interesting.

Unfortunately I am "cutting" my bricks with a diamond blade on a grinder and a hammer and chisel. I was planning on using some of the off cuts though. breaking them down a bit and filling the larger gaps.

I called the local potter who has no powdered clay.

Guess I am digging the stuff

I do not see why you need powdered clay the wet potters clay added to water and mixed to a slurry could be added to the mix water to incorporate into the home brew

[jes2xu]

I guess it becomes a issue of being able to get the right ratios? Weight will be totally thrown out due to the water content of the wet clay. Volume would be too, although to a lesser extent I guess?

But lets be honest . . . home brew is well . . . . home brew! Its not a exact science.

I agree in principle it should be exactly the same. Has anyone else tried this, or have a suggestion for getting close to the same ratio?

[JRPizza]

jes2xu, if you have a good scale, weigh a chunk of the wet clay, then dry it out (oven or whatever). Get a dry weight and you will have your ratio (hopefully your wet product is consistent, but if not just repeat the process for each new batch). You will probably have to hunt for a weight ratio for home brew, as the common one is by volume.

[jes2xu]

Yeah true,

Good way of working it. Would only take on extra measurement to work the volume into the formular too!

I may just give that a whirl in conjunction with the water extraction mentioned above.