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#1 Round2potter

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Posted 17 December 2012 - 04:34 PM

Dear all,

I have been taking a few days relaxing at the beach and brought with me a low fire cone pack to see what i can do with a beach fire.

It turned out i got washed out by the tide so i had to move my experiment to the woodstove in my house, not a fireplace, an insulated, high draft, super tall chimney, woodstove.

I had a ^021, a ^018 and a ^012 in the pack, the first 2 came out all blisters and melted while the ^012 was, as my mentor would say, "twitching" or just starting to bend.

I now have a little doodad i made in there now (i used ^10 stoneware clay with lots of grog).

When i get home to my camera i'll snap a few photos.

Has anybody ever done this before?

What kinds of glazes/slips/terra sigilata could i use at such low temperature to make a vessel that will hold water?

Or could just a simple burnishing job do the trick?

So if any of ya'll with pitfiring experience can chime in your 2 cents i would much appreciate it!

-Burt
"There is no such thing as cheating in clay; So long as it works"

#2 Round2potter

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Posted 17 December 2012 - 05:38 PM

I am going to add to this by the way that i used small orton cones, not the self supporting ones, nor the large ones. And they were some really really old ones i got from my mentor. They could be up to 30 years old.

Why did they blister like that????

I heard lead can do that in cones, do these low temp cones have lead in them? or did they used too, cause as i said these are really old.

Cheers!

-Burt

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"There is no such thing as cheating in clay; So long as it works"

#3 Marcia Selsor

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Posted 17 December 2012 - 07:12 PM

I would recommend using terra.sigilatta and buff or burnish the surface. iI bisque my pieces to ^09 before doing a pit firing.
It most likely won't hold water if you are using stoneware or even an earthenware.
There are sealers you could use but they would not be food safe.

The lowest glaze I know is about 09 . They could exist but I am unaware of them.

Marcia

#4 Round2potter

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Posted 17 December 2012 - 07:27 PM

I have a super extensive glaze book with some really really low recipes (^015) but i think they all use lead and i dont exactly want to get into any of that stuff......

I am not super attached to them being functional, like holding water, i'm all in this for the fun of it.

I made a few clay pipes, that is the doodad currently in todays wood stove firing at the beach; i am hoping it will take on resin from smoke an "color up" similar to meerschaum pipes

I did not bisque it before the fire, i took it up slow.....

Also i have a bowl (that was bisque fired) layed upside down on top to protect it from the logs and maybe act as a saggar and promote a slower heating and cooling for my small, rather delicate, piece.

My cone pack was done in this same way and did not crack or explode...... I microwaved the bone dry cone pack and pipe on LOW for about 30-45 seconds to really drive out any plastic water left.

Thanks!

-Burt
"There is no such thing as cheating in clay; So long as it works"

#5 Marcia Selsor

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Posted 18 December 2012 - 07:18 AM

Why does your cone pack look like Egyptian paste? What are you using to make it?
Marcia

#6 Round2potter

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Posted 18 December 2012 - 03:10 PM

I made the cone pack out of my stoneware clay (DWS from the Clay Art Center).
I am fairly certain that the color is from the smoke. At Bisque the clay is a dull pink and when high fired in OX it is a light tan/buff color and when it is in RDX it is very gritty, with lots of iron flecking; it almost looks like yellow/orange sandstone.

Have you ever had a cone pack bubble up like that? Do you think that the fact that they were heated well beyond their bending point that made them blister/bloat?

Cheers!
"There is no such thing as cheating in clay; So long as it works"

#7 Mark C.

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Posted 18 December 2012 - 05:01 PM

I am going to add to this by the way that i used small orton cones, not the self supporting ones, nor the large ones. And they were some really really old ones i got from my mentor. They could be up to 30 years old.

Why did they blister like that????

I heard lead can do that in cones, do these low temp cones have lead in them? or did they used too, cause as i said these are really old.

Cheers!

-Burt


Cones do not go bad or get old as long as you keep them DRY-I have cones that are over 30 years old and work just fine.
As far as lead in them I cannot attest to that as its a trade secret as to what's on the cones and Orton is not letting this info out.
Cones melt at exact temps and that means they are all formulated differently. Orton would tell you if lead was present.
My guess is you are firing in a wood fire/smokey environment and that cone is way overfired as well. What's the blue cone pad material-looks like playdoe?
MaRK
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#8 Round2potter

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Posted 31 December 2012 - 05:13 PM

Do to the utter failure of my basic up draft kiln; i have been doing a lot of firings in my wood stove.

I was able to find little shelves that work great in the cramped space; i think i am now on my 5th or 6th bisque fire in the stove (yes everything was green ware) and i seem to be really getting that hand of it.

The only pieces i have lost were due to either being a little wet still and todays' disaster that i took out with a log that toppled a shelf onto it breaking it instantly...........

Also, i have managed to get the hang of the damper to control the atmosphere; left open my pieces are a nice pure pink like i would expect form an electric kiln, and when i shut the damper (at peak temperature) they get smoked a bit. Also, covering the pieces with ash during the cooling gets things blackened and smoky.

I don't have any cones with me, but judging from the absorbency of the clay i would say that i am hitting ^08 easy. I'll bet i could get it hotter but i don't really feel like totally wrecking my wood stove!

My firing schedule is simple; i start the fire small and get it going with the damper closed and the door open, then after 45 minutes to an hour (when the peices are visibly black i shut the door and open the damper only enough to keep the fire from going out, if every i feel it is heating to fast i crack the door to let in cool air (shuting the damper accordingly). After the first gentle hour of babysitting i stoke it up and keep it there for an solid hour then i let it burn out (usually 20-30 minutes) then i crack the door to keep lots of O2 to prevent the blackening of peices and let it burn out completely.
It is probably best to let it cool naturally but i am typically so anxious to get it out i open the door as much as i can without smoke escaping and leave it untill i can pull out a shelf and put it on top of the stove where it can cool fast but not too fast.

Thats about it; i managed a 3 hour start to finish fire (finish as in holding a cool piece in my bare hand) yesterday with none of the pieces lost.

-Burt
"There is no such thing as cheating in clay; So long as it works"

#9 JBaymore

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Posted 01 January 2013 - 10:06 AM

Cones do not go bad or get old as long as you keep them DRY-I have cones that are over 30 years old and work just fine.
As far as lead in them I cannot attest to that as its a trade secret as to what's on the cones and Orton is not letting this info out.


In some of the very much older low range cones (can't remember how long ago... it seems like yesterday.... but it has to be 20+ years.....might be 30+)...... some cones did contain lead. I understand that Orton reformulated them many years ago. (They also came up with the L.I (low iron) cones for the 0 series a long while ago.)


Cones melt at exact temps and that means they are all formulated differently.


Actually cones melt (deform) based upon precise levels of heat work, not on temperature. It is a temperature and time relationship. That is why cone charts show "rate of climb" and differing end point temperature on them. For a given "cone value" .... if you fire at a faster rate of climb then the end point temperature reached (when the tip of the cone is curved down to the base) will be at a higher temperature than if you fire at a slower rate of climb.

best,

................john
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#10 Cone6

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Posted 01 January 2013 - 01:29 PM

I have collected roadside clay and fired it in the woodstove at our cabin with great success, and lots of fun doing it. Firepit on the beach not so successful, due to wind. I also brought some clay home, sieved the bigger rocks out, and threw it on my wheel. These came out a nice toasty orange-red at 04, darker brown when glazed clear and fired 05. Totally vitrified but not distorted at ^6. I'm going to try some of the clay in some ^6 line blends for glazing. The greatest success for woodstove firing was some rather thick 5 inch tiles with relief animal designs on them. Lots of fun.

#11 Round2potter

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Posted 24 January 2013 - 02:15 AM

Finally got around to uploading some photos of some of my woodstove firings!

Cheers!

-Burt

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"There is no such thing as cheating in clay; So long as it works"

#12 Marcia Selsor

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Posted 24 January 2013 - 06:01 AM

I had a kiln that had a longer fire box, about four ft. Long , 20 " wide and 24 " high going to a beehive shape about 3 ft at the base and tapered up to 30". On top of that was a fiber lined oil drum on pulleys. All the bricks were fire bricks. House bricks are not a good idea.

I was worrying about your fire place firings. Normal wood stove insulation may not be rated for high intensity burns. be really careful with that.

Marcia

#13 Marcia Selsor

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Posted 24 January 2013 - 06:02 AM

I had a kiln that had a longer fire box, about four ft. Long , 20 " wide and 24 " high with grates half way up the fire box, going to a beehive shape about 3 ft at the base and tapered up to 30". On top of that was a fiber lined oil drum on pulleys. All the bricks were fire bricks. House bricks are not a good idea.

I was worrying about your fire place firings. Normal wood stove insulation may not be rated for high intensity burns. be really careful with that.

Marcia

#14 Diane Puckett

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Posted 24 January 2013 - 07:26 PM

How is this different than a pit firing? Have you tried this with pieces that have been bisqued?
Diane Puckett
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#15 Round2potter

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Posted 25 January 2013 - 01:29 AM

yeah i have, the bisque ware usually gets nice and smoky but most of the time i feel like it gets hotter than the smoke can stand. most of my pieces come out pink and bisque-ee like they came out of an electric kiln.

Marcia,

I agree that it is kinda risky, but this woodstove is good, also i am not really firing it THAT much hotter than normal woodstove use.
A four foot fire box would be so much fin; this old beehive wood stove sounds like dream!

-Burt
"There is no such thing as cheating in clay; So long as it works"

#16 OffCenter

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Posted 25 January 2013 - 11:08 AM

Cones melt at exact temps and that means they are all formulated differently.


If that were true there would be no need for cones. Each cone melts at a WIDE RANGE of temps because it is measuring heat work (time and temp).

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#17 Mark C.

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Posted 25 January 2013 - 03:13 PM


Cones do not go bad or get old as long as you keep them DRY-I have cones that are over 30 years old and work just fine.
As far as lead in them I cannot attest to that as its a trade secret as to what's on the cones and Orton is not letting this info out.


In some of the very much older low range cones (can't remember how long ago... it seems like yesterday.... but it has to be 20+ years.....might be 30+)...... some cones did contain lead. I understand that Orton reformulated them many years ago. (They also came up with the L.I (low iron) cones for the 0 series a long while ago.)


Cones melt at exact temps and that means they are all formulated differently.


Actually cones melt (deform) based upon precise levels of heat work, not on temperature. It is a temperature and time relationship. That is why cone charts show "rate of climb" and differing end point temperature on them. For a given "cone value" .... if you fire at a faster rate of climb then the end point temperature reached (when the tip of the cone is curved down to the base) will be at a higher temperature than if you fire at a slower rate of climb.

best,

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


Jim
John covered this very well a few posts up. I still have cones from 40 years ago actually from the 50s as well which may have lead as they are low #s like 017.
Mark
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#18 OffCenter

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Posted 25 January 2013 - 04:31 PM

I still have cones from 40 years ago actually from the 50s as well which may have lead as they are low #s like 017.
Mark


I have no idea what it has to do with anything but congratulations on having 40-year-old cones. That must make you very proud!

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#19 Round2potter

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Posted 26 January 2013 - 01:45 AM

I thought some used to have lead. I think i read that in an old book i have (50's) in a section on reduction firing

Cheers
"There is no such thing as cheating in clay; So long as it works"

#20 OffCenter

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Posted 26 January 2013 - 08:02 AM

I thought some used to have lead. I think i read that in an old book i have (50's) in a section on reduction firing

Cheers


They probably still do have lead in them. Why would they want to remove the lead?

Jim
E pur si muove.

"But it does move," said Galileo under his breath.




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