Blue clay

Hi my name is carter, I am going to be building a RMH in my home. I live in north east Ohio and one of the sand and gravel places has what the call blue clay also known and grey. I will be using fire clay around the unit but I wanted to know if anyone here has experience with that clay and will it hold up for the cob bench.
I think I am going to try to get a sample to test tomorrow

Any advise would be great.
Thanks Carter

Hello Carter- How'd it go?
I'm in the area too, and made mine with blue clay. Not a problem, dried hard as chicken lips.

Carter Bailey : Ernie Wisner is very clear that the history of Blue, Blue-grey clay is so unfortunate that when found, Blue clay is condemned out of hand as (probably)
not containing Enough Alumina-silicates! The one potter I have spoke to about blue clay thought they knew It could make a terra cotta !

Two things, if it appears to feel soapy, slippery, it probably will not work! but you should do a sedimentation rate (Google it!) and any chance to practice making bricks
is worth the time it takes to practice! Ether perform the test and ask Ernie for his own second opinion or do not waste his time- He Is meaner than me ! Big AL !

Hi Al- can you explain why blue clay is a poor choice, breaking it down for me?

Kilgore Belle : The very best I can do is to send you to> www.traditionaloven.com/acticles/101/ here you will find a quick link to what makes a good fire clay!
It is my understanding that while there maybe a little Blue or Blue gray clay that does indeed have a decent amount of Alumina-silicates, that the general view is to
regard this type of clay as both poorly binding and of such a high expansion rate as to guarantee a lot of expansion and contraction caused cracking ! I Welcome any
second opinions,comments, or observations ! Think like Fire, Flow like gas! Don't be a marshmallow ! As always Comments and questions are solicited and welcome !
Pyro - Logically Big AL!

Thanks for the quick reply. Read it while sitting on my toasty warm blue clay bench. It's true though, it does have some cracks in it, but that's purely cosmetic and I am pretty sure the lime wash will take care of that.

Hi Kilgore,

I think the main point Al is trying to make, is "test," and don't make generic assumptions positive or negative. As a Natural Builder, and a Ceramicist I can tell you that the term "blue clay" is like saying a "blue fish" or a "blue bird." Not very descriptive, other than it's clay and its bluish in color. Some are excellent and others aren't clay at all, just a blue silt soil with "clayish" characteristics. You need to do a sedimentation rate test, make practice bricks and measure for shrinkage and cracking, look at abrasion resistance, and you may (I would) make a small cup and open fire it to bisck just to see how it holds up. Then you will know if you have a good clay body or a something else.

Hi Big Al.
I have been busy and haven't been on here at all. Since I was here last, I did find some good brown clay and also made some bricks in the oven. My ratio of 1 part clay to 3 parts sand worked out great. Nice solid brick not much shrinkage and no cracks. I wish I already had it in place but don't yet. I do have all the insulation and layout in the dining room done and my core is also done.

Hi Kilgore. I am happy to hear that the blue clay worked out good for you. I bet it looks great. I would like to see a picture of it.

Carter Bailey : There is an old cooks saying that translates very well (I THink) 'No matter where I feed my guests, they always like my kitchen best ! This usually has to due
with its warm toastiness, and the coffee pot, than with how good the cook is !

I expect that you will find that your new rocket with become the heart of the home-which is what Hearth first meant - and its location much more of a family room than even
now! Good luck !

We will want to see lots of pictures from the outdoor tests to the final Hand Sculpting of your new-built-in-furnature ! Howare you dealing with the weight issues and protecting
your exposures ?! Big AL

Here's two; the back rest and arm rest are freshly coated and wet. The bench is hard and dry. The is a loaf of bread cooking on the barrel.

Hi big Al. I hope you had a good thanksgiving. I ended up building a molded core and it burns awesome. After hours of burning it hardly even gets warm on the outside. I will be adding a support but with the location it's not even needed. The insulation I have to protect the floor is 3" thick and also fireproof. Awesome stuff. Thanks to my friend jeff that gave it to me. Here is a pic of the location and insulation in place. I will also cover it with foil before I start construction. Sorry it's a big pic.

Hi Carter. I'd love to hear how it goes. My friend Chris McClellen and I have built a few RMH in Cleveland and Burton, OH. I'll be organizing a NEO Natural Building get-together for this spring, but don't know many people in Akron. Please send me an email at clevelandnaturalbuilding@gmail.com if you'd like to be involved. Thanks!