Novice Firing Question

[Potter3ee]

Please excuse me if my question seems stupid. Im quite new to this. I want to fire a stoneware - first bisque, then with a white glaze and finally paint it with underglaze colors and fire again.

 

The clay I am using is Laguna B Mix 5 WC 401 which fires at cone 5. 

The white glaze I want to use is Amaco dry glaze C10 snow which fires at cone 5-6

I would paint with underglaze that says it should be applied to cone 04 bisque ware and fired to cone 06.

 

Now my question is how do I fire? Can I do a bisque fire at cone 5. Then glaze fire at cone 5. And then again a low fire for the underglaze at cone 06 ? Or do I need to use a low fire clay that fires bisque at cone 04?

[Pugaboo]

Tanvi504 - welcome to the forum.

 

There are a few issues with your plan and a few ways of getting around them.

 

Do NOT bisque fire your cone 5 clay to cone 5, your clay will be fully vitrified at that point and it will be impossible to get the white glaze to stick to it. Most Underglazes will remain dull if not covered in a clear glaze and some will burn out at cone 5 if not covered with a clear glaze.

 

Now for suggestions on how to get you where you want to go...

1) Paint your bone dry piece with a white underglaze

2) Paint your design work on using your underglazes

3) Bisque fire to cone 04

4) Glaze your piece with Amaco HF-9. This is a Zinc free clear that doesn't affect and cause strange things to happen with your underglaze colors. Regular clears can at time do so.

5) Fire your glazed piece to cone 5

 

Alternative suggestion...

1) bisque fire your piece to cone 04

2) glaze your piece with the white you have chosen

3) use Mayco Stroke n Coat to paint your design. This line of glazes turn glossy at cone 5. This will not work if your white glaze runs AT ALL. If it does it will cause your design work to move as well and possibly ruin it.

4) fire your glazed and painted piece to cone 5

 

Now I highly recommend making a couple of test pieces and try out both ways to see what turns out best. I hope this helps and good luck let us know how it turns out.

 

T

[Dick White]

Underglaze is just what the name suggests - it is color to apply under the final glaze. Some people apply the underglaze to the greenware before bisque firing, others apply it to the bisqued piece. Then apply the final glaze and fire to maturity. Almost all underglazes state on the label that it is to be fired to 06-04, suggesting that underglazing is a low fire technique. For some colors (such as bright reds and yellows), the color will burn out at higher temperatures. Other colors will survive. You have to test which will work.

 

Finally, you indicate you want a white glaze background with the color visible on top. If you use a white glaze over the underglaze, the color will be obscured. Underglazes are usually used with a clear final glaze. I suspect the effect you are looking for is what is called majolica. That is a completely different process.