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Frost Warping Issues


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#1 Corinda Genev

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Posted 23 June 2013 - 07:24 AM

I switched a few months back from B-Mix to Frost 6 (studio fires to cone 7) for making jewelry because I wanted my unglazed fired pieces to be white.
Unfortunately, the warping issues were huge, pieces that went in flat came out concave - incidentally I also make some flat decorative wall tiles, came out looking like demented bowls ;(

I'm wondering if I would have less warping issues in my jewelry if I change to Frost 10 (fired at cone 7),
has anyone tried this? Would it come out too weak?

What about mixing Frost 6 with a little Frost 10, is this do able? Would it increase the firing temperature?

Thanks for the help!!

#2 OffCenter

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Posted 23 June 2013 - 08:11 AM

I switched a few months back from B-Mix to Frost 6 (studio fires to cone 7) for making jewelry because I wanted my unglazed fired pieces to be white.
Unfortunately, the warping issues were huge, pieces that went in flat came out concave - incidentally I also make some flat decorative wall tiles, came out looking like demented bowls ;(

I'm wondering if I would have less warping issues in my jewelry if I change to Frost 10 (fired at cone 7),
has anyone tried this? Would it come out too weak?

What about mixing Frost 6 with a little Frost 10, is this do able? Would it increase the firing temperature?

Thanks for the help!!


Even though the box says Frost 5 meaning fire to cone 5, it is really a cone 6 clay. It is stronger and more translucent at 6. I usually fire it to a flat 6 which means 7 is bending so I guess you I'm really firing it to 6 1/2 - 7. If translucency is important to you do not mix Frost 10 with the Frost 6. It will still be translucent but not as translucent as without 10. My suggestion is to try different ways of making your tiles and jewelry. The stresses you put on the clay when rolling it, for example, can cause a tile to crack or warp. If you roll from the center out, try rolling from the edge to the center and flipping the clay to roll from different directions, and compressing it from the sides with a slat, etc. In other words test. OR, switch to a another clay. If whiteness is what you're after there are a lot of porcelains that are almost as white as Frost and less temperamental.

Jim
E pur si muove.

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

#3 Marcia Selsor

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Posted 23 June 2013 - 08:18 AM

I agree with Jim. I use Frost 5 and fire to a flat 6. I haven't used it for hand building but you can try several methods.
Rolling out in several directions and flip the slab. Try dropping slabs while on a board onto the floor. Elizabeth Priddy technique mentioned by Chris Campbell.
Is the studio firing gas or electric? Try firing pieces lifted off the shelf on coils to allow even heating.
Firing pieces directly on the shelf means one side gets heated faster than the other.

Marcia

#4 Corinda Genev

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Posted 23 June 2013 - 08:41 AM

I agree with Jim. I use Frost 5 and fire to a flat 6. I haven't used it for hand building but you can try several methods.
Rolling out in several directions and flip the slab. Try dropping slabs while on a board onto the floor. Elizabeth Priddy technique mentioned by Chris Campbell.
Is the studio firing gas or electric? Try firing pieces lifted off the shelf on coils to allow even heating.
Firing pieces directly on the shelf means one side gets heated faster than the other.

Marcia


Marcia, thank you for the tips. My studio uses electric kilns. I found the post you mentioned and I must agree with many of the other people, looks quite dubious - much too simple to be true.
But I will definitely give it a go and cross my fingers that I don't accidentally drop it on my toes and flip it mid air Posted Image

#5 Chris Campbell

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Posted 23 June 2013 - 10:41 AM

Yes, the method does seem too simple to be true ... But it works every time. My tiles are all flat no matter how big or small I make them.
Handling causes warps ... No matter how light the touch the porcelain will warp in that spot.
Why doesn't clay memory ever work in our favor??? : - )

Chris Campbell
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TRY ...   FAIL ...  LEARN ...  REPEAT


#6 Claypple

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Posted 23 June 2013 - 03:16 PM

Wouldn't it also help if you cover it with a plastic bag for evenness while drying it?

#7 Marcia Selsor

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Posted 23 June 2013 - 04:14 PM

Clayapple,
Yes, drying slowly covered with plastic is a good practice, but Corinda's pieces were flat when going into the kiln. Drying unevenly would warp something before the firing.

Marcia

#8 Claypple

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Posted 23 June 2013 - 11:15 PM

Clayapple,
Yes, drying slowly covered with plastic is a good practice, but Corinda's pieces were flat when going into the kiln. Drying unevenly would warp something before the firing.

Marcia


Oh, I see.
Correct me if I am wrong with this one too: I use a paddle to "slam" the clay instead of rolling the slab. I think it prevents warping too.
It is close to the dropping the slab in a sense that it shakes the clay too and forces it to line up the certain way. Again, correct me if I'm wrong. Anyway, I think it is easier to slam it than roll the slab with the rolling pin.

#9 Marcia Selsor

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Posted 24 June 2013 - 11:21 AM

I agree that slamming is a good method for preventing warping as well.
I still use a slab rollover and rotate and flip the slabs as the get thinned. That works too.

Marcia

#10 Brian Stein

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Posted 24 June 2013 - 12:30 PM

I pound the clay into roughly the size slab I need then cut to thickness with a wire and shims down the side - no rolling. When drying tiles I put wax resist on the edges as soon as leather hard and cover loosely for several days. The wax resist keeps the edges from drying faster than the middle which could be your problem. Even if they do not warp in drying, the tension from edge to middle could be stored and released when the piece is fired.

-B

#11 Benzine

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Posted 24 June 2013 - 12:41 PM

I pound the clay into roughly the size slab I need then cut to thickness with a wire and shims down the side - no rolling. When drying tiles I put wax resist on the edges as soon as leather hard and cover loosely for several days. The wax resist keeps the edges from drying faster than the middle which could be your problem. Even if they do not warp in drying, the tension from edge to middle could be stored and released when the piece is fired.

-B


I've used wax on thin slab pieces as well. In my case, the smaller, thinner slabs, were attached to a larger slab sculpture. I didn't want them to dry as quick as they normally would, as they would have possibly warped and cracked/ separated from the rest.
"Anything worth believing, is worth questioning"

#12 Marcia Selsor

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Posted 24 June 2013 - 01:07 PM

I paint wax on the edges of my large raku slabs too. I dry them on sheetrock and don't touch them until they are dry. My slabs are 24 or so inches and stay nice and flat for my drawings in raku.

Marcia

#13 Corinda Genev

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Posted 25 June 2013 - 09:04 AM

I agree with Jim. I use Frost 5 and fire to a flat 6. I haven't used it for hand building but you can try several methods.
Rolling out in several directions and flip the slab. Try dropping slabs while on a board onto the floor. Elizabeth Priddy technique mentioned by Chris Campbell.
Is the studio firing gas or electric? Try firing pieces lifted off the shelf on coils to allow even heating.
Firing pieces directly on the shelf means one side gets heated faster than the other.

Marcia




Does this mean most of you think that the warping issues have more to do with my methods than my firing schedule being above the clays intended cone?

Jim - have any porcelain recommendations for cone 7? The only ones that I could find were cone 5-6 and cone 8-10 - clay makers don't seem to be able to count well, because they completely forgot about 7 :(/>

Thank you to everyone for your help

#14 OffCenter

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Posted 25 June 2013 - 09:23 AM


I agree with Jim. I use Frost 5 and fire to a flat 6. I haven't used it for hand building but you can try several methods.
Rolling out in several directions and flip the slab. Try dropping slabs while on a board onto the floor. Elizabeth Priddy technique mentioned by Chris Campbell.
Is the studio firing gas or electric? Try firing pieces lifted off the shelf on coils to allow even heating.
Firing pieces directly on the shelf means one side gets heated faster than the other.

Marcia




Does this mean most of you think that the warping issues have more to do with my methods than my firing schedule being above the clays intended cone?

Jim - have any porcelain recommendations for cone 7? The only ones that I could find were cone 5-6 and cone 8-10 - clay makers don't seem to be able to count well, because they completely forgot about 7 Posted Image/>

Thank you to everyone for your help


I'd recommend staying with Frost 5 for cone 7. Try what Chris and others suggested. Frost is so beautiful that it is worth the effort to make it work. It is at its best at 6 1/2 to 7. Test first because it may be a little high for what you make and, unfortunately, some batches of Frost aren't as good as others. Several years ago I tested a lot of cone 6 and cone 10 porcelains but decided that Frost 5 for cone 6 and Southern Ice and Frost 10 for cone 11-12 woodfire were the best and have forgotten most of the others. I rememeber Mile Hi's (in Denver) Aspen was a runner up. One that I didn't test but looks good in the 7th post to the following thread http://ceramicartsda...__fromsearch__1 is Tacoma Clay Arts NZ6.

BTW, I visited your profile gallery which led me to your Etsy site. You're tiles are wonderful!

Jim
E pur si muove.

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

#15 J. Stickle

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Posted 27 June 2013 - 08:18 PM

Yes, the method does seem too simple to be true ... But it works every time. My tiles are all flat no matter how big or small I make them.
Handling causes warps ... No matter how light the touch the porcelain will warp in that spot.
Why doesn't clay memory ever work in our favor??? : - )


Chris,

I have read the comments on the drop method - put on board and drop twice on floor. At what stage of the process is this done? Or perhaps the better question is what hardness of the clay is it done at? The other thing I do not understand here is, if you are carving the clay, do you work the clay before or after the "drop(s)" Thanking you in advance.



Jeff

#16 Chris Campbell

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Posted 27 June 2013 - 09:23 PM

I drop blank tiles as soon as they are cut to shape ... so very wet, fresh from bag.
When carving or adding on sprigs ... as wet and soft as possible.
Bad news is that if you are being very precise and fancy, the dropping may skew the image ... so if you have to repair it you must do so without lifting.
Sometimes this just does not work out so you have to go back to careful drying.

Chris Campbell
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#17 Corinda Genev

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Posted 27 June 2013 - 11:38 PM



I agree with Jim. I use Frost 5 and fire to a flat 6. I haven't used it for hand building but you can try several methods.
Rolling out in several directions and flip the slab. Try dropping slabs while on a board onto the floor. Elizabeth Priddy technique mentioned by Chris Campbell.
Is the studio firing gas or electric? Try firing pieces lifted off the shelf on coils to allow even heating.
Firing pieces directly on the shelf means one side gets heated faster than the other.

Marcia




Does this mean most of you think that the warping issues have more to do with my methods than my firing schedule being above the clays intended cone?

Jim - have any porcelain recommendations for cone 7? The only ones that I could find were cone 5-6 and cone 8-10 - clay makers don't seem to be able to count well, because they completely forgot about 7 Posted Image/>

Thank you to everyone for your help


I'd recommend staying with Frost 5 for cone 7. Try what Chris and others suggested. Frost is so beautiful that it is worth the effort to make it work. It is at its best at 6 1/2 to 7. Test first because it may be a little high for what you make and, unfortunately, some batches of Frost aren't as good as others. Several years ago I tested a lot of cone 6 and cone 10 porcelains but decided that Frost 5 for cone 6 and Southern Ice and Frost 10 for cone 11-12 woodfire were the best and have forgotten most of the others. I rememeber Mile Hi's (in Denver) Aspen was a runner up. One that I didn't test but looks good in the 7th post to the following thread http://ceramicartsda...__fromsearch__1 is Tacoma Clay Arts NZ6.

BTW, I visited your profile gallery which led me to your Etsy site. You're tiles are wonderful!

Jim


That's so kind Jim, you just made my day!!




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