Is my soil clay content high enough for rmh??

I live in southern ontario canada, we have clay rich soil but I'm not sure if there is enough clay in the soil. I just filled a jar half way with my soil and the rest with water gave it a good shake and a stir and am watching it settle as I type this. I have most of the materials to begin my build just need the clay, vermiculite and the odd piece of pipe.

I am just wondering if anyone can offer some guidance as to what exactly I am looking for. I've read that everything other then the clay will settle in short time, but what if there is too much of everything else is there options. Possibly a way to filter out sand and collect the 'clay water' then add builder sand afterwards. The weather here is steadily reaching below zero (sorry celcius here) so I would like to get this built asap.

Im at about 10 min. into the settle and I see about 1 inch of sand. There is a top layer about a half inch of almost see through water, im thinking there is no clay here oh great....There is about 4 inches of muddy looking water??

Oh ya forgot to mention, I did find small globs of what seemed to be pretty pure clay, very gummy but this would be very tedious to pick out these small pieces. Im hoping someone knows of some kind of filter idea that i can just wash this soil through to collect the clay.

If I could just buy some for cheap that would be great but am having trouble finding anything other then potters clay which is a little outside my price range.

Sorry to whom ever read this I should have waited a bit longer before typing. It seems that this i silt causing my soil to pack together I guess I will just dig deeper in the garden and do more research.

Hi, ya might try searching the net for 'refining clay soil', I found articles & videos about the subject.

For me, I dig past the top 10" of soil, to get to a layer of clayish dirt. Still lots of roots & rocks below 10", but the color is different, mine is kind of whiteish, or red, depending where I dig. Try to dig the clay dirt while dry, if possible, it is alot lighter and easier to sift if dry. I cover the hole with plastic while not digging, so it remains fairly dry. Shovel the dirt, rock, roots onto a piece of 1/4" 'rabbit cage wire' that is stretched across the top of wheel barrow. Sort your rocks out and save the dirt in the wheel barrow. If ya store your sifted dirt, cover it to keep it dry. When you got a big pile of it, get your buckets of water, and put the dirt in a bucket, 3/4 full of dirt, add water & stir, scrape off the 'slag on top', then find a old window screen and place that over another bucket. Pour your well stirred muddy mix thru the window screen into the other bucket. Waste what the screen catches. What is left in the bucket is thick muddy water. Let that sit for a day if you can, pour the extra water off the top (a square bucket works better than a round bucket for this). What is left in the bucket should be sticky wet clay, there will be sand that settles in the bottom. Let that stand for another day, pour off any water on top, until eventually you get some stiff mostly clay stuff.

james beam

Thanks alot that was very informative. I filled a jar about half full with dirt about 2ft down in my garden mixed it up well and let it sit. the sand settled first then about half hour later there was about four inches of mud then about an inch of almost clear water on the top. I read somewhere that the clay will stay suspended/dissolved in the water for a long period of time. Im sorry if im not making sense but im new to this stuff but very interested. I am sort of in a time crunch now before the frost sets in but have been researching the soil studies in my area and it says we have lay present and is common.

I guess im not sure about how the clay will seprate in the water with the other materials. I will try your technique as soon as im sure i have the right dirt. Thanks again.

ya well actually the clay is the slippery stuff in the water, it 'likes water' and the sifting or straining the muddy liquid is removing the contamination out of the clay mud, that is why the first time you mix the dirt & water I stir mine thoroughly using my finger and hands, till there are no 'dry lumps' of dirt in the solution. This solution is full of clay, but it also has other stuff in it, like leaves, wood, small stones, roots, sand, bugs, whatever~~so that is why you pour the thoroughly mixed muddy solution thru a window screen, to catch all the contamination to the clay. You want just the clay, because you want something that is sticky, and will kind of hold together when 'dry'. If you just leave all the contamination in there, it won't be sticky enough, it would just be normal mud....haha like in a mud puddle. So first strain out as much contamination as you can get out of the solution, then let it settle for a day or two, as the water separates and rises to the top, do not stir!...tilt the bucket, pour the extra water off the top, when the clear water is poured off, your clay solution is still in the bucket. Try letting it settle for another day if possible, to remove more water. The clay is in the bucket, once the water is poured off or evaporated. There might also be silt & sand in the bucket too, but I don't know how to get those out.

james beam

I was looking at one process on the net that showed using a clear jar. You mix the clay sand with the water just wait until the sand settles which happens fast then you pour the clay water into another bucket/jar. You can repeat this process to remove more sand.

I just finished running my mud through a screen and have the clay/sand mix settling in some buckets. I already have a bunch of dirt dug up so I couldn't resist. We will see how it turns out.

Now i'm wondering is there a good test I can do to see the quality of the clay, and if it will be good enough for my combustion unit on my rmh. I may just buy clay from a pottery supplier for the combustion unit. I also need strong enough clay to hold up for the mass/bench.

well I guess, if you naturally have alot of sand in your dirt, (as you see it in your clear jar)....then I would try to 'let it settle overnight', without stirring, pour the clear water off the top, then pour the 'clay slip' into a different bucket...BUT stop pouring before you empty the bottom of the bucket (which is where the sand is....settled first). Pour off the clay slip you want, leave the muddy sand settled in the bottom, and don't pour that into your clay slip bucket. The clay is stickier if it doesn't have sand in it. Once you get your hands in it and work it you will figure out what is good to keep and what feels gritty with sand. I think pure clay slip will feel slippery like a bucket of oil...almost. Once you get 'mostly clay' in a bucket, let it settle overnight, pour the water off again, repeat, till eventually the stuff gets stiff enough to mold into a ball. Smash it around beat it until it gets drier & drier it should be sticky enough to use. Did you try the permies forum? lots of topics & info: https://permies.com/forums/f-55/stoves

james beam

Thanks again, you've been very helpful. As for the other forum that is where I have been posting I just had thought that this is more related to the outer structure and building materials for the bench. But you are right that would probably be a better place to post my question since I am trying to get a clay consistency good enough to build a rmh.

John,Hi
In my experience with cob ( a couple of bread ovens, a bench and helped on a cottage),it is the sand that is the structural material. The clay is used to bind the sand together. Often the ratio is 3 sand to 1 clay in a cob mix. Some silt is acceptable. I've worked with pure clay( from an old brick factory) and sand,along with sand added to just what was dug from the ground.
I suggest you take some of your present dug out earth and make some different ratio mixes...you might actually have the perfect mix just from what you dug out. Does it pull together and form a shape? Does it hold this shape when rolled into a snake or dropped from waist height to the ground?
Stomp it,add a bit of sand and some water and see how it functions. Make a few bricks of the various ratios and let them dry.
When I do the water shake test,sometimes it is difficult to define the silt layer from the clay.
Maybe get another earth sample from somewhere else and try it,too. ?From a recently dug basement/fundation site?
All the best with your project.
Kate

Thanks Kate, out of my first pile i dug up I made a small about 1.5 inch diameter ball a left it to dry. The ball now is very hard I have dropped it from about chest height to the coffee table and it has stood up. A small log or snake I had trouble rolling so I just left it at the ball. The dirt I have dug up is pretty dark compared to what I have seen on the internet, although it is a fair amount lighter then our topsoil. My batches the first with just screened soil and the second with screened soil where I have let the sand settle and poured the top mud while leaving the sand in the bucket. My plan is to make maybe an ashtray out of each batch and cook it in the wood stove. Feel the strength then maybe put it back in the fire for a few more heat and cool cycles. Im not sure of any other way to test it for the purpose I need it for.

I will make just straight bricks and let them dry naturally as well I should have enough to make a few test models from each batch. Thanks again for your time and sharing your experience with me. Is there a good size to make these bricks for testing, and what should i do with them after just try to break them or subject them to heat, then heat and cold repeated.

John,Hi

I would find a couple of different locations of clay earth and mix them to various ratios with sand and water. Mixing with your feet on a tarp will grind the clay down and adhere it to the sand particles. Once it's mixed, make up a ball of this and drop it from waist height to see if it stays together. With various ratios, make brick size bricks and leave to dry. Checking for cracking and general durability. I wouldn't dry them with forced heat although please know that
I have no experience with building a RMH.
All this being said, Erica and Ernie Wisner, moderating the woodburning stove section of this forum, would be the best to ask regarding your RMH cob concerns.

Best wishes.
Kate