Jump to content
Sign in to follow this  
Isculpt

Red Earthenware Appropriate For Pit Firing?

Recommended Posts

I have two red earthenwares on hand, one smooth, the other not so much.  I'd like to make something from the smooth clay and burnish it before slowlybisquing it to around 018, then pit firing it.  Is it likely to be able to withstand the thermal shock?  Or would I be wasting my time on something that's more ikely to crack into shardsl?

Share this post


Link to post
Share on other sites

 

 

Why are doubting the clay bodies that you have. I'm sure their firing temps. Are much higher than 018.

 

Thermal shock can sometimes be tamed with the addition of grog. Are you thinking that the coarser clay is groged therefore more shock resistance?

 

Like any thing in pottery you don't know until you try/test. A pile o shardsl is still data.

 

The historical process of pit firing, usually used indigenous earthenware, which is going to be much less a stable clay than commercially available clay, assuming your clay is commercial clay.

 

I've seen clays that are groged successfully burnished. If I had to choose I'd choose the coarser clay.

 

If allowed I'd choose smother clay and grog it up with maybe include some mica...other I'd start the burnishing process on the wheel/ or early in building process. Maybe this would help prevent a pile of shardsl.

Share this post


Link to post
Share on other sites

Red earthenware should be fine . . . smooth or with grog, especially if you bisque before pit-firing. Your bisque temperature at 018 is likely to be higher than the pit fire temp, so the clay should not be stressed as much. To be on the safe side, I'd build the pit firing temperature gradually/evenly and let the fire pit cool as slowly as possible. That way you can manage the firing/cooling stress on the clay. A red commercial earthenware should be no different than what you dig naturally.

Share this post


Link to post
Share on other sites

Jayne, I pit fired with my classroom clay, which is. low fire white. The first time, I tried to go "old school" and not bisque. I had nearly a complete loss. Those that "survived" had terrible spalling. And I even added saw dust to the body, to help with the shock. The second time, I bisqued the wares first. I had zero issues, and some nice smoke patterns.

Share this post


Link to post
Share on other sites

My summer classes in Montana use to dig our own clay, process it, add fine mica or pumice.Decorate with terra sig. Bisque to 09. Go out to a ranch, collect cow pies, dig a pit, build a bed of coals with wood with pots toasting on the edge, , put the preheated pots on a grill (refrigerator shelves) set on a ledge in the pit above the coals, cover with very ample supply of dried cow pies and seal with sawdust and cove with sheet metal scrap a la Maria Martinez.Often Montana school budget for are was zero, so this class show ways to use local supplies. How to run an art program on very little.

 

The fire would burn through to the top in about 2.5 hours and then we'd wait til it cooled down. Fun days.

 

Marcia

Share this post


Link to post
Share on other sites

Hey,

Firing earthenware is very close to firing natural clays. If you are

planning to bisque them, they are probably the same. I never bisque

my primitive pottery but have used red earthenware clay to see how it

compared to the natural river clay. There wasn't any mica in the red

earthenware and because of the lack of yellow oxides the distinct

flash marks were missing. Some clays will not crack below 6 inches

diameter but everything over 6 inches will require a type of temper

in order not to crack. And sometimes the best remedy for cracking

pottery is to find another river with better clay. If you fire

each pot based on its own merits, the results will be a 100 percent

success rate. So by all means, make the pottery.

Winter is a good time to fire pottery outside.

Good luck.

Alabama

Share this post


Link to post
Share on other sites

Thanks, all.  Some of you remember the recent fiasco with the 500 lbs of hand-dug clay that looked like it was going to be great clay but had no strength whatsoever.  My husband dug it from the traditional tribal clay holes, and despite all the helpful advice offered here, and additions ranging from creek sand to crushed fired pots, nothing seems to help.  He's using it for pieces that are under 3-4", but his hands are itching to make real pots.  Until he can return to the (now off-limits) clay holes, he's looking for something that approaches it in color.  Nothing at the Highwater Clay site looks similar, but he's hoping red earthenware might give him something like the image below (after firing it with wood & bark in the traditional shallow indentation in the ground).  We'll see.....!

 

Jayne

post-1258-0-47102400-1418692875_thumb.jpg

Share this post


Link to post
Share on other sites

Oooooooooh, what a great idea!  We've never made terra sig but there are tons of videos about it.  He couldn't sell the work as traditional, of course, but it would look awfully nice in my house (and like most artists, we don't get to keep much of our own work...)  Thanks!!!  jayne

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.