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Are A Couple Fine Cracks In Floor Of Kiln Normal?

New kiln fired 6 times

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#1 Pugaboo

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Posted 03 September 2013 - 03:34 PM

I just unloaded my kiln and since this was my 6th firing in a new kiln decided it was time to remove the shelf I have sitting on 1/2 inch posts in the bottom. It's there to help protect the floor of the kiln from glaze runs and to all the air to circulate under the shelf for the vent. I noticed after I removed this shelf that the floor of the kiln had a couple fine cracks running across it. I laid on the floor and looked up from underneath and do not see that they go all the way through. They do not seem to follow the frame of the metal base either nor do they follow the grout between the fire bricks. They also do not line up with the post positions. I did kiln wash the inside floor of the kiln again to protect the bricks from glazes.

So is it normal for these fine cracks to appear after the kiln has been used a few times? How do I know if I have a problem?

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#2 Arnold Howard

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Posted 03 September 2013 - 03:51 PM

Cracks in the firebrick floor are pretty common and generally nothing to worry about. They do not need to be repaired.

 

Sincerely,

 

Arnold Howard

Paragon Industries, L.P.,

Mesquite, Texas USA

ahoward@paragonweb.com / www.paragonweb.com



#3 Pugaboo

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Posted 03 September 2013 - 04:39 PM

Arnold - Thank you

T
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#4 oldlady

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Posted 03 September 2013 - 04:57 PM

how did the firing come out?


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#5 Pugaboo

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Posted 03 September 2013 - 09:00 PM

Oldlady - Beautiful! The 18 test tiles really show the colors and textures of the glazes I used on them and will make choosing which glaze to use so much easier. The long oval dish I made came out perfect and the small tray I tried doing UG design work under a colored glaze looks really good. I tried out a whole bunch more ornaments and some small jewelry pieces and they all worked too. I did 4 more small dishes and unfortunately 1 of them developed a slight crack on the outside that didn't go all the way through and it's smack in the middle of a flat smooth area so not sure why it cracked there as its not an edge or anything, maybe when I pressed it in the mold folded a piece of clay over there or something. I can't sell it but can use it for change or something myself. But if that's the only issue I had I am pleased, I'll just make up another or sell the other 3 as individual bowls. I'll see if I can't take a picture of some of the stuff and show you.

Have some design work to do on greenware then it'll be time to do a load of bisque next.

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#6 Stephen

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Posted 04 September 2013 - 09:43 AM

Hi Terry,

 

a little off topic but you mentioned selling your work. What venues are you starting with? Are you selling just pottery or blending with the other mediums you work in?



#7 Marcia Selsor

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Posted 04 September 2013 - 11:18 AM

I always coat my kiln floor with kiln wash. That helps protect it from glaze drips.
The cracks happen with settling.
Marcia

#8 neilestrick

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Posted 04 September 2013 - 01:03 PM

Fine cracks are normal. Large cracks, or cracks that go all the way through, are not. Double check that your kiln is sitting properly on the stand. If the kiln rocks at all, you need to put shims under the legs of the stand to even it out. Rocking indicates that all 4 legs of the stand are not sitting solidly on the floor, generally due to the floor being uneven. When this happens, the floor of the kiln will flex under the weight of the shelves and pots. If it flexes enough, the floor will crack all the way through. Be sure to use something on-flammable for the shims, like sheet metal or washers.


Neil Estrick
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Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com

#9 Pugaboo

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Posted 04 September 2013 - 02:28 PM

Hi Terry,

a little off topic but you mentioned selling your work. What venues are you starting with? Are you selling just pottery or blending with the other mediums you work in?

I've been an artist for over 20 years doing painting, photography, digital and graphic arts, I am new to pottery. In the past I have done art festivals, galleries, eBay, etsy and my own websites. With pottery I am starting small and have my work in a local gallery and hope for more when I have enough work. I am also doing a couple group festivals and another festival by myself that takes place over 2 weekends. I plan to only do local festivals since its just too much work and too much time away from home to do long distance national festivals. My new rule is I have to be able to sleep in my own bed each night. As the holidays get closer I'll be listing art and pottery on ebay and etsy. Once I get through the holidays I plan to add pottery to my website as well. I have recently relocated to a new state along with recovering from medical issues that sidelined me for 2 years so I am basically starting over in the art world. As I said I am going slowly introducing pottery with my other art forms and am going about this on a smaller scale.

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#10 Pugaboo

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Posted 04 September 2013 - 02:35 PM

Fine cracks are normal. Large cracks, or cracks that go all the way through, are not. Double check that your kiln is sitting properly on the stand. If the kiln rocks at all, you need to put shims under the legs of the stand to even it out. Rocking indicates that all 4 legs of the stand are not sitting solidly on the floor, generally due to the floor being uneven. When this happens, the floor of the kiln will flex under the weight of the shelves and pots. If it flexes enough, the floor will crack all the way through. Be sure to use something on-flammable for the shims, like sheet metal or washers.


Neil - I checked the stand and kiln again and it seems very stable and does not move or rock. I put metal shims under 2 of the legs when I originally installed it to get it level and they are still in place. The cracks don't look like they go all the way through and I checked by sitting a flash light on top of the crack inside the kiln and laying on the floor next to it and looking up underneath and saw no light nor could I see any cracking on the outside bottom. I will keep an eye on the crack and if it looks like its widening or something I'll have to do something about it. I wonder why they don't put a solid steel plate on the bottom of kilns? Or why the stand is not big enough to stick out a bit all the way around the kiln rather than fitting up underneath it like it does. It seems to me the stand is just supported by the brick floor and not much else.

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#11 Arnold Howard

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Posted 04 September 2013 - 02:44 PM

 I wonder why they don't put a solid steel plate on the bottom of kilns? Or why the stand is not big enough to stick out a bit all the way around the kiln rather than fitting up underneath it like it does. It seems to me the stand is just supported by the brick floor and not much else.
Terry

 

Terry, you could slide a piece of sheet metal between the kiln stand and the firebrick bottom. You can buy the sheet metal from a hardware store. It should be large enough to protect the entire firebrick bottom.

 

Sincerely,

 

Arnold Howard

Paragon Industries, L.P., Mesquite, Texas USA

ahoward@paragonweb.com / www.paragonweb.com



#12 neilestrick

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Posted 04 September 2013 - 03:41 PM

 

Fine cracks are normal. Large cracks, or cracks that go all the way through, are not. Double check that your kiln is sitting properly on the stand. If the kiln rocks at all, you need to put shims under the legs of the stand to even it out. Rocking indicates that all 4 legs of the stand are not sitting solidly on the floor, generally due to the floor being uneven. When this happens, the floor of the kiln will flex under the weight of the shelves and pots. If it flexes enough, the floor will crack all the way through. Be sure to use something on-flammable for the shims, like sheet metal or washers.


Neil - I checked the stand and kiln again and it seems very stable and does not move or rock. I put metal shims under 2 of the legs when I originally installed it to get it level and they are still in place. The cracks don't look like they go all the way through and I checked by sitting a flash light on top of the crack inside the kiln and laying on the floor next to it and looking up underneath and saw no light nor could I see any cracking on the outside bottom. I will keep an eye on the crack and if it looks like its widening or something I'll have to do something about it. I wonder why they don't put a solid steel plate on the bottom of kilns? Or why the stand is not big enough to stick out a bit all the way around the kiln rather than fitting up underneath it like it does. It seems to me the stand is just supported by the brick floor and not much else.

Terry

 

 

L&L makes a solid top stand. Much more supportive than the frame type. But like Howard said, if you're worried you can alway put a piece of sheet metal down there. Some brands do/used to have a piece of sheet metal mounted to the bottom of the kiln, attached by tabs to the sheet metal skin on the sides. It seems like a good idea to support the floor, but it's really a mess. The sheet metal always rusts out and causes a huge headache trying to get a vent to mount properly under the kiln. I've had to dig out the rusted metal on many kilns. A sold stand, or an easily changeable piece of unattached sheet metal between the stand and kiln is a much better option.


Neil Estrick
Kiln Repair Tech
L&L Distributor
Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com

#13 Stephen

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Posted 05 September 2013 - 09:45 AM

 

Hi Terry,

a little off topic but you mentioned selling your work. What venues are you starting with? Are you selling just pottery or blending with the other mediums you work in?

I've been an artist for over 20 years doing painting, photography, digital and graphic arts, I am new to pottery. In the past I have done art festivals, galleries, eBay, etsy and my own websites.

 

 

 

 

Best of luck, can't wait to see your new pieces when you post them. Sounds like your background will certainly give you a fast start. Would love to read some of your sales experiences in the business section.






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