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Joseph

Need A Cheap Simple Clay Body Recipe

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I'm looking for a cheap and simple stoneware body recipe. I would like to use as much XX since that't the cheapest bagged clay. I would also use sand instead of grog. I fire to around cone 9/10. My pots are fired green in about 8 hours. I'm hoping that this would lower the formation of cristobalite to the point were I would not need feldspar. I've also read in a Nils Lou book if I quick cool at the end of firing I can avoid a lot of crisobalite formation. I consider myself a craft potter and care nothing about color effects and so on. My only goal is cheap, simple and usable.

 

thanks 

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We need a lot more info from you. What type of kiln are you using? What type of work are you making?

 

XX Sagger is not necessarily the cheapest bagged clay. Maybe from your supplier, but not everywhere. And when it comes right down to it, all clay is cheap in the big picture. The cost of the clay is very small compared to the retail value of the work. Trying to make clay as cheaply as possible should not be your primary goal in formulating a clay body. First and foremost should be a body that will work well for what  you are doing. Clay is not cheap if your pieces crack, slump, bloat, etc. A clay body should also be vitrified well for functional work, which means you need feldspar. The color and texture of your clay will have a huge impact on the look of your pots, so it's essential to making a clay body selection.

 

Are you set up to mix your own clay body safely? As in very good ventilation? Clay dust is the #1 health hazard to potters, and simply wearing a mask while mixing clay is not adequate. The smallest particles can stay airborne for hours, so good ventilation is essential.

 

Give us some more info and maybe we can come up with something.

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I'm currently making pickling crocks in the 10 pound range. As I said before they are green fired with a few different glazes mostly ash based. The kiln is wood fired and of the olson fast fire variety. The most important thing for me is to keep the pots in a range I consider affordable. I'm running out of the free clay I was able to obtain and would like this to have a minimal impact on my prices. Looking into mixed ver. self mixed I believe I can save about 60%. I have lots of time so I'm not worried about mixing. All the clay I currently have is dried solid in buckets so I'm used to the labor. 

 

About the spar, opinions seem to vary as to its addition. Is it for fusibility or to reduce cristobalite? 

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Guest JBaymore

About the spar, opinions seem to vary as to its addition. Is it for fusibility or to reduce cristobalite? 

 

For both.  If you are doing pickling and using ash glazes... you likely should attend to how vitreous the body it.... those ash glazes will likely craze.

 

The "cheaper" the clays you try to use as the base body, the more "issues" are likely going to crop up.  It could be a case of "pay me now or pay me later".

 

best,

 

......................john

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One way to get your clay cheaper is to buy in volume, as in a pallet of ball clay,etc.If your clay is unknown, you risk bloating as you are firing up to temp.

I would look at slip glazes,for glazing the insides of your crocks, as in Albany slip types. Some of these also contain ash, but the surface is smoother and more hygienic.

TJR.

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The cheapest clay body will not be your friend if you're single firing 10 pound crocks in a wood kiln.

 

At 60%, you're going to save about $2 per crock. Not worth the time and effort to mix your own clay in my opinion. Buy some good commercial clay, add $2 to every crock, and spend your time making and selling pots.

 

All the recipes I have use ball clay in a relatively small percentage, so won't be of much help in keeping your costs down. I'm a big fan of fireclay and kaolin!

 

Here's a good all around cone 10 body:

20 Kaolin

20 Fireclay

20 Ball Clay

20 Feldspar

20 Filnt

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I like making my own clay. But I realize as many say here that it in dollars it doesn't make sense.

I don't have a pug mill, or mixer.

It does repay by saying you make your own clay, fine tuning blend to your needs, and the satisfaction of making ones own clay.

Also if xx is cheap it means your relatively close to mine which also means your sourcing local ish material which makes,ecological sense.

I recently got a my first glazed wood fire piece back. And it was crazed. (And love it ) Granted there is ash, and kiln contributions to glaze.

 

You should check out the dick lehman 12d body, and the slightly modified slightly modified 12d. Which I have been using. I can get. Epk is local so it is least expensive next to silica. This clay body is almost (self glazing , if you will, in wood kiln environment. See making clay 101

 

As long as the pieces are not to be used in a commercial kitchen. And your clay is vitrified, Let it craze.

 

I've done some reading the cristabloite issues you mention is greatly over simplified. I haven't been exposed to any clay body that doesn't use some type of spar/feldspar.

 

I like what saggar xx does in wood fire. I have another clay recipe listed in making clay 101. That utilizes it. And it came out beautiful and flashy. I plan on experimenting more with xx more.

 

Did I tell you I'm jealous that you have access to a wood fired kiln!!!

 

Do you have pictures of your pickling crocks?

 

Where (approximately) is this kiln located?

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I think I'll try 

 

60 % fireclay

10-20 % XX

5-10% sand

5-10 % spar, wollastonite maybe a touch of talc

 

any pointers or tips would be appreciated.

 

I'm located in western north carolina.

 

I realize that mixing clay will be time consuming, time I could be throwing but it seems to me to be part of the process not separate from it. 

 

thanks

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Good luck with body
What size sand /silca do you have
Any chance you have gold art?
What kind if fire clay?
Do you have any porcelain?
Clay and glazes for the potter. ---Rhodes , Is the most info I've been able to find on making clay bodies?
What method are you mixing clay with?

With out notes/books fire clay percentage looks high.

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That recipe should be fine to start with. May need to tweak the feldspar as you go.

 

I'm not trying to be negative, but here are some thing to think about in regards to mixing your own clay:

Personally, I don't feel like I'm missing anything by not mixing my own clay bodies. I know how to do it, I did it for a few years, and I'm done with it. For me it's better left for those who can do it quickly and efficiently and safely. As long as I can get a body I like from a commercial supplier, I'm happy to do it. And if the day comes that I can't get one, then I'll still have them mix my own recipe for me. Generally speaking, painters don't make their own oil paints and printmakers don't make their own inks. Most fiber artists don't raise their own sheep and spin their yarn. Most furniture makers don't raise and harvest their own trees for lumber. There are things that you shouldn't feel bad about leaving to someone else. You're going to put a lot of wear and tear on your body, and if your studio isn't properly vented for dealing with dry clays, then you're also creating a big health hazard with all that dust. If mixing your own clay is necessary for the process to feel complete, why aren't you digging your own clay? If you truly love mixing clay, then go for it. But don't feel like it's something you need to do to be a 'real' potter.

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Guest JBaymore

Joseph,

 

As to educatiing a "well rounded potter", I am all for learning about making clay bodies from scratch.  I teach about that activity in my college classes.  BUT I also spend time teaching about ceramic toxicology.  And the concept of "transference of risk" is something that gets stressed for that "well ropunded potter" also.  Knowing when it is time to contract out some activity that you cannot set up to do safely in a cost effective manner.

 

Maybe think of making your own clay from scratch for a limited production kind of work.... with the body being distinctive and "special" (and the pieces costing more becasue of that to pay for the labor and risk and uniqueness)... and leave the bulk volume general production body mixing to a commercial supplier. It can still be your own recipe they mix up.  Only spend the time and risks needed to develop the body to your liking in relatively small  amounts (hundered of pounds per test batch)....and once it is "there'.......  then contract out the mixing work to a place that is equipped to handle the stuff relatively safely.  The minimum order is usually 2000 lbs.... which for someone doing serious production work...... is not that much clay.

 

The health hazards for the potter go up exponentially with stuff like bulk clay mixing from dry commercially prepared ingredients.  "Folk potters" never had as big an issue because the raw materials they they used to mix the clay were not commercially "beneficiated".  The bagged dry materials we get are produced mainly for industries OTHER than for wet clay pottery making... and the fine-ness and particle size distributions of the powders is WAY more easy to get airborne than our pottery ancestors ever dealt with.

 

I know a number of potters with diagnosed silicosis... and I know at least two with lung cancer.  Of course... anecdotal evidence here....... could have nothing to do with their clay work..... but then again......... .  Clay (and other silica-bearing ingredients) are KNOWN human carcinogens.  And also are KNOWN to cause silicosis.  We can't get away from ALL of the risk......... unless we stop working with ceramics........ but we can minimize it.

 

The cost to set up local pickup ventilation systems in an interior space that will control the dust to keep it below OSHA/MESA PELs / TLVs will be VERY expensive.  Makes that "cheap" clay very expensive (unless you go into commercial production.... and then the per pound cost over thime and volume will come down to reasonable levels). 

 

The alternative is to risk your health..... which is also very expensive.

 

As a wood firer, I'm one who is all about the "process" too....so I understand the allure of making your own clay.  Doing it all in more involved and maybe primitive (by today's standards) ways is seductive.  And I do make the "specialized" bodies myself (in limited amounts).  But I also have a decent small scale mixing and local pickup vent system....that was put in 35 years ago when you could do such stuff far more affordably. 

 

But when you "cut to the chase"....... REAL potters just make good pots.

 

best,

 

..............................john

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i mix clay outside,   me standing up wind with mask.

Im asuming the mask and "natural" ventilation system is just as safe if not safer than indoor filtration

 

speaking of masks i read that the n95 mask, isnt such a good choice?

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http://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/n100list1.html

 

The N95 respirator is the most common of the seven types of particulate filtering facepiece respirators. This product filters at least 95% of airborne particles but is not resistant to oil.

 

The N100 particulate filtering facepiece respirator filters at least 99.97% of airborne particles but is not resistant to oil.

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Guest JBaymore

For the level of hazard that microcrystalline silica presents, the recommended maks is a half face with p-100 (HEPA) filters.

 

If you KNOW the actual level of the contaminant that you are being exposed to, then you can calculate the combination of the protection factor for the style of mask and the filter's efficiency and compare those numbers to the PELs that will get through the mask.  But if you don't know the numbers (most of us don't)... then it is always safest to err on the side of caution (overkill).

 

best,

 

.....................john

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Thanks for all the feedback. I spoke to the person at highwater that formulates new clay bodies and they thought using granite dust instead feldspar would be a good sub. I can get the ungraded dust for a song at the stone yard. I was thinking it would work well as an aggregate also. The other free material I have access to is the tailings from a granite/stone(marble,soapstone maybe even some cultured stone aka concrete) counter top place. These are a very fine powder. What do folks think about this as a feldspar sub?

 

I currently do my mixing outside and use a n95 dust mask. Sounds like I should get the better filters. By the way I'm the type of mule headed person that has made furniture from trees I cut down.

 

thanks!

 

Oh and I can get goldart.

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The materials from the counter top place won't be consistent form batch to batch, so you'll have to run a bunch of tests each time you get some. Not the most efficient way of doing things. Is the stone yard a quarry, where their getting all their stone from one place? If so, that would be a more consistent product.

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FELDSPAR is cheap and consistient why shoot your self in the foot,   now granite chips in clay is different story.    but from the sound of it you need a solid functional consistent vitrified body.

 

ive read where some suggest that no more that 33% of any one ingredient,  i personally will go as high as 40%. 

 

i feel like gold art is the great equalizer in clay bodies

 

john and neil   know way more about his than i do.

 

im just hard headed enough to want to make clay, like you.  prolly about a year  and about 5 different bodies deep.  im almost satisfied with my wood fired bodies, im now working on mid range bodies right now

 

ive read lucie rie made her clay in 5 gal buckets.....

 

im also thinking since natural ash glaze may be foe,  maybe drop your temp final cone which means making a clay that matures at lower temp and fire "faster" maybe even less reduction atmosphere,   trying to prevent the ash from glassing up. ok that sentence just broke a bunch of traditional wood fire "rules", and i recently got a few pieces back from wood fire that stayed pretty much white. which has me thiniking about your project. but that was on a porecelain based body.   you dont say what part of country your from?  if your near helmer idaho i imagine that porcelain would come inexpensive also

 

you might take some notes on korean onngi pots   but thats prolly a whole different kind of pickle ......

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I thought I should follow up on this thread and report on my findings. 

 

I made two bodies based on a 60/40 blend of hawthorne 40 and XX sagger + 2.5% pioneer talc.

 

The first body I added 10% yellow builders sand the second I added 10% 16 mesh granite dust.

 

The granite body shrank quite a bit more than the sand body and the granite melted on the surface leaving small dark spots(I thought it was quite pretty). The granite body had less water absorption but both were in the acceptable range for vitrified pottery.  The sandy body did not explode when force dried in my oven the granite body did. They both were a bot difficult to trim well the granite was very hard to trim but the sandy body just comes out a little textured.

 

Based on these findings I will say that it is possible to make a simple body that can deal with the rigors of green firing. The total cost for a 250 pound batch is about $80. This is dry weight. I purchased a 200 gallon plastic stock tank which I pour maybe 25 gallons in the bottom add the dry ingredients in layers and mix with a dry wall mixer attached to a hand drill. Age for a few weeks and it's ready to go.

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Thanks for the update. For 32 cents a pound you can select from dozens and dozens of commercially available pre-mixed bodies and save yourself a lot of time and effort, and get something you want instead of something that's just in the right price range.

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I have to agree with Neil about the availability of good clays for good prices. Your experiments are interesting. I think an addition of large mesh feldspar with the sand may give you some cool spotting. But it is an arduous task you are on.

I am sure Neil did not intend any offense. I didn't see any there. He is generous and helpful.

There are some things that are more efficient like spending your time making pots. Unless you are trying to develop a marketable alternative clay body.

 

Good luck with it if that's where you are headed.

Marcia

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I recognize that clay bodies are good but it really only takes about 20 to 30 minutes to mix the clay. And of course I have to wedge it but I wedge my bagged clay almost as much as this stuff. I've included a photo of the two samples. I guess I have more time on my hands than the average person. I also use a kick wheel like some backwards luddite.

post-61694-0-06550100-1432247545_thumb.jpg

post-61694-0-06550100-1432247545_thumb.jpg

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Hey, I say let him make his own clay. ^_^ If he wants to break his back (like I did) doing this stuff, I say more power to him! I gotta say, though, I am not a self-mixer, but would have luvved to get further into it before I broke myself. I think it's just a step some people feel they need to take on their journey (like glaze mixing or throwing v. handbuilding, etc.). We all eventually find our stride, right? :) And, who knows? Maybe he'll come up with that new clay that everyone just has to have. :)

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I would say that in a forum called "Clay and Glaze Chemistry" Joseph's enquiry is right on the money.  We should give him all the encouragement we can and be appreciative when he shares some of his experience back with us.  Where do you think all those wonderful commercial clay bodies everyone keeps referring to here came from anyway?  If no one experimented we would all still be pit-firing river mud.

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