[LilyT]

Hi, Everyone!

Does anyone have experience in using Macabee White (from Clay Planet).
It's listed as a cone 10 clay that is good for wood fire. I'm curious as
to what people might think about any aspect of it - throwability, wet strength
for large or medium forms, fired strength, flashing, survival while firing to
say, cone 11... or 13 or 14 :-).

Feel free to compare to any other clays you might have
used for wood fire. (Or soda)

Thanks in advance for any input you might give!

Warmly,
Lily

[Chris Campbell]

I don't have experience with this particular clay but because I hate to chip and grind clean kiln shelves ... I would want to use a clay that matched the temp I was firing to. Why do all the work of making and lose it in the firing?

[LilyT]

Hi, Chris, I don't have a very good understanding of how a clay is
rated and what it actually fires to. Laguna for instance has their
set categories but then the clay is obviously named for something
somewhat different (i.e. wood fire b-mix is in their cone 10 section,
but wood firing often goes much higher and this clay can be
used at those temperatures). Clay Planet's Macabee is obviously
'made for woodfire' since that's their advertising, but the bag I
just got says 'cone 7-10'. I don't find the official instructions
helpful perhaps because they are avoiding liability issues? So I
guess your comment addresses one of my issues head-on, I'm
just hoping others have had experience that will tell me thumbs
up or thumbs down before I have to grind some shelves :-).

I would love for a manufacturer to say : buttery porcelainoid white
clay with excellent workability to medium size and fires up to cone
12-13 without bloating but matures sufficiently at cone 9-10 to
avoid dampness seeping through the finished piece. Now that would
be my clay!

But if no one else has experience, I will post mine later (probably in
a few weeks, since I only have the bag of clay and a partially
assembled stack of kiln materials at present.) Macabee throws
decently in the first pieces I've used it on - In small bowls to 8 inches,
it is sightly less strong than Laguna's wood fire b-mix, (it is a
porcelainoid clay), but smooth and pleasantly non-sticky - less smooth
and more sticky than my current bag of woodfire b-mix.
(more smooth and much less sticky than Laguna's cone 5 b-mix)
I'm looking to throw fairly light functional ware with a smooth
surface.

Thanks for chiming in :-)!

Warmly,
Lily

[JBaymore]

Lilly,

Their Grogzilla bags from Clay Planet are also labeled cone 7-10.............. and I regularly fire it to cone 14.

Shefield Ceramics Supply's #42 is rated as cone 8 oxidation only...... and I also fire that to cone 10 in my woodfired noborigama.

Nothing beats testing.

best,

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

[Chris Campbell]

Ok ... So here is a dumb question ... Why don't they mark the clay accurately? Surely this isn't beyond their technical ability? Is it a case of once it gets to Cone 10 it'll go anywhere?

[timbo_heff]

JBaymore, on 15 August 2012 - 12:03 PM, said:

Lilly,

Their Grogzilla bags from Clay Planet are also labeled cone 7-10.............. and I regularly fire it to cone 14.

Shefield Ceramics Supply's #42 is rated as cone 8 oxidation only...... and I also fire that to cone 10 in my woodfired noborigama.

Nothing beats testing.

best,

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

actually 42 is called a 6-10 recommended for ox or reduction.
I've taken it to 11+ in wood

[LilyT]

John, That is good to know about Grogzilla. I have also fired their
grogzilla to higher than labelled. (but not as high as 14 :-)). I guess
it makes me nervous at first that even if my test goes well, that
clay may not fire well in the future. (on the other hand, why do I
figure that labelling it would make it any more reliable?) Probably
the answer to Chris' question would give us more guidance.


Another clay that fires to way higher than rated temperature successfully is
Long Beach red. I had some of the long beach white, but it does
not throw nearly as well and I've only fired it to cone 10.

[LilyT]

timbo_heff, on 15 August 2012 - 11:25 AM, said:

JBaymore, on 15 August 2012 - 12:03 PM, said:

Lilly,

Their Grogzilla bags from Clay Planet are also labeled cone 7-10.............. and I regularly fire it to cone 14.

Shefield Ceramics Supply's #42 is rated as cone 8 oxidation only...... and I also fire that to cone 10 in my woodfired noborigama.

Nothing beats testing.

best,

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

actually 42 is called a 6-10 recommended for ox or reduction.
I've taken it to 11+ in wood

Thanks, timbo_heff. Interesting how you can really stretch the
upper range on some of these bodies.

[JBaymore]

timbo_heff, on 15 August 2012 - 02:25 PM, said:

JBaymore, on 15 August 2012 - 12:03 PM, said:

Lilly,

Their Grogzilla bags from Clay Planet are also labeled cone 7-10.............. and I regularly fire it to cone 14.

Shefield Ceramics Supply's #42 is rated as cone 8 oxidation only...... and I also fire that to cone 10 in my woodfired noborigama.

Nothing beats testing.

best,

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

actally 42 is called a 6-10 recommended for ox or reduction.
I've taken it to 11+ in wood

I think originally it said what I mentioned. But I've been mentioning to them for years that I fire it in a wood kiln to far higher heat work. Maybe they finally changed it. .


best,

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

[LilyT]

So I called Clay Planet last week and talked to one of the guys (because now it's
listed as out of stock) and he said he'd used this himself for wood fire.
He said that it flashed well and would be good above cone 10, but he didn't give me
a number. I tried to get him to be more specific (as in when does it slump or bloat)
but he wasn't biting. I don't know if it's policy to not give details, or they maybe don't
use cones, or what? I'm not good at squeezing information out of people, lol.
Isn't there anyone out there who's used it or tested it to destruction?

[btrengove]

LilyT, on 19 August 2012 - 04:25 PM, said:

So I called Clay Planet last week and talked to one of the guys (because now it's
listed as out of stock) and he said he'd used this himself for wood fire.
He said that it flashed well and would be good above cone 10, but he didn't give me
a number. I tried to get him to be more specific (as in when does it slump or bloat)
but he wasn't biting. I don't know if it's policy to not give details, or they maybe don't
use cones, or what? I'm not good at squeezing information out of people, lol.
Isn't there anyone out there who's used it or tested it to destruction?

I have taken it to cone 11 in electric kiln. I have no clue about wood firing it.
It can get hairline cracks in hi stress locations on detailed cut outs of slab work.
I have never had a problem with thrown pieces.

As far as the out of stock issue. I live near their store and last time I went to pick it up they had an unstable batch.
They pulled it off the shelves -at least they don't sell it when it is bad!

[LilyT]

btrengove, on 20 August 2012 - 08:20 PM, said:

LilyT, on 19 August 2012 - 04:25 PM, said:

So I called Clay Planet last week and talked to one of the guys (because now it's
listed as out of stock) and he said he'd used this himself for wood fire.
He said that it flashed well and would be good above cone 10, but he didn't give me
a number. I tried to get him to be more specific (as in when does it slump or bloat)
but he wasn't biting. I don't know if it's policy to not give details, or they maybe don't
use cones, or what? I'm not good at squeezing information out of people, lol.
Isn't there anyone out there who's used it or tested it to destruction?

I have taken it to cone 11 in electric kiln. I have no clue about wood firing it.
It can get hairline cracks in hi stress locations on detailed cut outs of slab work.
I have never had a problem with thrown pieces.

As far as the out of stock issue. I live near their store and last time I went to pick it up they had an unstable batch.
They pulled it off the shelves -at least they don't sell it when it is bad!

Hi, btrengove! Thank you so much for your information, and specific
insights about Macabee... it helps me quite a bit! I want to fire it
as thrown pieces (and rarely do I do cutouts) so your experience
bodes well for that use.

What kind of work do you do - I'd be interested to hear about what you
make and like and why you fire to cone 11 electric as it's not something
I've really come across that before. (but then again there's so much
I don't know Please tell us more about it if you don't mind!

And thank you for the info about Clay Planet pulling it off the shelves
because it was an unstable batch. They did tell me it was back.
Good for them about not selling something known to be suboptimal.
I am changing clays because I hope to find a more reliable supplier. I
understand there must be strong economic pressures in supplying clay at good
prices, but I've been stuck with 2 bad tons now from Laguna
West and managing that as a hobbiest takes up a large proportion
of my actual pottery time (not to mention I could never get my
recent batch of B-mix to ever stop blistering, what a waste.)

So nice to meet you, welcome to posting on the forum!

warmest regards,
Lily

[timbo_heff]

Chris Campbell, on 15 August 2012 - 12:22 PM, said:

Ok ... So here is a dumb question ... Why don't they mark the clay accurately? Surely this isn't beyond their technical ability? Is it a case of once it gets to Cone 10 it'll go anywhere?

Just a thought on why it's hard for clay makers are not more specific when they rate their clays above cone 10:

It's easy to test a body in electric and gas for cone but most folks who fire over cone 10 do so in wood.

There are so many factors that effect the clay in a wood firing from the style of the kiln, to the style of the kiln master, rate of climb, to reduction cycles, to fluxing from the ash, to hot and cold areas.
So there is no way to guaranty what is going to happen to the clay when they can't know what the person is going to do to it.

It's not possible to replicate a a firing schedule in everyone's wood kiln the way you can easily duplicate in every person's electric kiln "set kiln to fast glaze cone 9" .

I try to make a note when someone tells me they took T3 to cone 14 beautifully, or the porcelain slumped at 13 so when someone asks if will work for them I can at least be able to say anecdotally, that I've heard of it working or I've heard of it not working. That way we can try to steer you with educated guesses and always with the caveat:
please, please, please test it with your forming methods and firing methods before you make your whole years work with it.

[JBaymore]

timbo_heff, on 21 August 2012 - 02:21 PM, said:

That way we can try to steer you with educated guesses and always with the caveat:
please, please, please test it with your forming methods and firing methods before you make your whole years work with it.

Wise wise words there, Tim.

Drives me nuts with students that suddenly decide to try something new and basically untestes on a large body of work....... on the last major firing for their senior thesis show.

best,

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

[LilyT]

JBaymore, on 21 August 2012 - 11:30 AM, said:

timbo_heff, on 21 August 2012 - 02:21 PM, said:

That way we can try to steer you with educated guesses and always with the caveat:
please, please, please test it with your forming methods and firing methods before you make your whole years work with it.

Wise wise words there, Tim.

Drives me nuts with students that suddenly decide to try something new and basically untestes on a large body of work....... on the last major firing for their senior thesis show.

best,

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

I do like to hear people's exact experiences, just so I can figure out if it's likely to apply to me,
or how I might choose to use it.

timbo_heff, isn't the idea of using cones to replicate some standard of heat work so that firings
can be compared? When I hear someone say they fired something to cone X, I expect they
mean that the pot was in an area that reached that cone, and within a certain moderately
limited variation. (and that the cone wasn't overly glazed by the atmospherics). Glazes understandably
may be extremely sensitive to small differences, but shouldn't the
body be more resilient? Can you use an example to help me understand why it might be
that large ash deposits might affect certain body characteristics like bloating and slumping?
I can see that if you fuse the entire foot of the pot to a shelf, the pot may crack upon cooling,
but it would be pretty clear that wasn't the clay's fault maybe?

john. Well, those students are testing it on work of the size and caliber they wish to use the clay on. Maybe
just can't imagine how much variability there may be? I test, and when I find something that works,
I use more of it, but my (admittedly much more limited than your) experience in the last couple of decades
makes me feel that clay production is not reliable. In fact the studio pug at the craft center was
more reliable than any of it's component parts - it never bloated, slumped, blistered, bubbled, or
did any of those catastrophic antisocial behaviors of my 'pure' clays, lol.

It's these horrible irredeemable failures I'm asking about.

So I'm also curious whether there are any pot shards from history that are recovered
with these defects showing? A fired pot is forever, right? Surely the ancient potters
with much less sophisticated control of their supply lines had some errors of this time?
I thought you might know some examples of this, being at an academic site, John?

warmest regards,
Lily