Firing question

[B.H]

Hi Community, 

I am quite new to ceramics and have a question re firing that I hope someone may be able to help me with! (Not sure if it’s a stupid question so please bear with me haha) 

I have made a piece which is ready to fire, but I want to leave it unglazed. 
I am not sure whether it should be fired to bisque and left, or fired to bisque and then fired again to earthenware, or whether it can be fired straight to earthenware! 

 

Hope someone may be able to kindly offer their expertise, and thank you in advance:) 

[Chilly]

Earthenware and bisque are so close to the same temperature, one firing will (should) be sufficient.  

At the centre where I volunteer, we fire both at the same time.

If you want it higher fired, it can be done in one firing, but must be very (very) dry.

 

[Pres]

Fire it as bisque, and if not happy with the color, use a stain over top to adjust the color/value and refire it. If the piece has texture, the stain would be the best way to make the texture stand out. You can apply the stain to the bisque, and wash/sand off the high areas leaving more the natural color, but the texture will have accents.

 

best,

Pres

[Babs]

If firing it yourself, follow bisque ramp to 600°C then can adapt faster firing to top temp you require.

If in studio ,i.e. you not in control, a bisque to Cone 04 would be fine imo

[Kelly in AK]

Unglazed work is not a problem in any way, it has to do with what you want it to look like. Chilly mentioned that earthenware and bisque are basically identical temperature ranges. If you’re new to ceramics, understand that people can be technical without realizing they’re speaking a different language. All parties walk away thinking they communicated when they did not. Bisque essentially is earthenware, and would require no separate firing, so I’m wondering if by “earthenware” you mean something else. You could be thinking of unglazed stoneware. 

I think this comes down to the clay you’re using. Clays are rated by temperature (and other ways, such as plasticity and shrinkage). The three common ranges are cone 06-04, cone 5-7, and cone 9-11. Clay undergoes a change in its character when fired to maturity (its cone rating). 

[B.H]

On 5/29/2023 at 1:59 PM, Chilly said:

Earthenware and bisque are so close to the same temperature, one firing will (should) be sufficient.  

At the centre where I volunteer, we fire both at the same time.

If you want it higher fired, it can be done in one firing, but must be very (very) dry.

 

Thank you Chilly, that’s helpful:) 

[B.H]

On 5/29/2023 at 8:31 PM, Pres said:

Fire it as bisque, and if not happy with the color, use a stain over top to adjust the color/value and refire it. If the piece has texture, the stain would be the best way to make the texture stand out. You can apply the stain to the bisque, and wash/sand off the high areas leaving more the natural color, but the texture will have accents.

 

best,

Pres

That’s interesting I did not think of doing this, thank you Pres 

[B.H]

On 5/30/2023 at 1:09 AM, Babs said:

If firing it yourself, follow bisque ramp to 600°C then can adapt faster firing to top temp you require.

If in studio ,i.e. you not in control, a bisque to Cone 04 would be fine imo

Thank you Babs:) 

[B.H]

On 5/30/2023 at 8:43 AM, Kelly in AK said:

Unglazed work is not a problem in any way, it has to do with what you want it to look like. Chilly mentioned that earthenware and bisque are basically identical temperature ranges. If you’re new to ceramics, understand that people can be technical without realizing they’re speaking a different language. All parties walk away thinking they communicated when they did not. Bisque essentially is earthenware, and would require no separate firing, so I’m wondering if by “earthenware” you mean something else. You could be thinking of unglazed stoneware. 

I think this comes down to the clay you’re using. Clays are rated by temperature (and other ways, such as plasticity and shrinkage). The three common ranges are cone 06-04, cone 5-7, and cone 9-11. Clay undergoes a change in its character when fired to maturity (its cone rating). 

I see!! (As I say, I am very new and am still trying to learn about clay properties, language ect! So that’s really useful). I think I was under the impression that firing to eathernware, being a slightly higher temp would make the piece more durable and less prone to breakage than if it was left at bisque! That is useful to know that I should be looking at the range of temperature my clay should be fired at to help gauge. 
Thanks.