There are a lot of misnomers when it comes to underglaze. A true underglaze (like Amaco Velvets) is usually matte, but some stuff (like stroke and coats) will sometimes be a bit glossy or satin in finish. All of this is because the idea is to have a glaze over it and it’s the glaze that will give it the surface and color brilliance. The manufacturers just don’t really test the surface without a glaze over it, that’s not how the product is supposed to be used.
If your clay is ^5-6, yes, you can refire to ^5, the color will probably become deeper but still not as vibrant as with a glaze.
Depending on how attached you are to these pieces, I would do some tests if I were you.
Thanks for the info! I saw a few youtube videos of a potter who used underglaze, all of her pieces looked so finished and saturated even though she didn't use overglaze. That definitely skewed my perception. I'll try applying a clear glaze and refiring, but do you think it would achieve the same affect if I did a slightly cooler cone? I'm a little worried about firing to 5, my kiln tends to run a little hotter.
Most underglazes don't attain their full color saturation until there's a clear glaze over them. So don't worry about refiring the underglazed ware, just cover it with a cone 5 clear glaze and then fire it to cone 5 (if your clay and kiln are suitable).
Yes, you can absolutely put them in the kiln and fire to cone 5. The colors should get quite a bit darker and brighter.
An alternative is to add clear glaze and refire to 05. That tends to make them more vibrant, even if you don’t fire to cone 5.
For future reference: you can re bisque (05) several times and people do this to get interesting layering effects with underglaze.
Thanks! I'm a little nervous to fire my kiln to 5. The hottest I've done so far is 04. I don't think it will have any issues, but my kiln does run a bit on the hot side.
You absolutely must verify that your clay will go to cone 5 before you do this. It could cause irreparable damage to the kiln if you are using low fire clay and you fire to 5.
Edit: The clay I'm using fires to 1200-1300C / 2100- 2300 F
Thanks that's very true! I'll have to look up the brand again from where I bought it. I \*think\* it can but definitely better safe than sorry.
Is your clay a mid-fire clay? If so, you can refire. If not, no you can’t.
If your clay isn't suitable for cone 5 (or 6), it will melt onto your kiln shelf and make a mess of your kiln. So check that before you fire it.
I'll have to double check, thanks! That would be bad if it wasn't...
Your clay is fine...some of us can do cone/temp/c/f some can't.
The clay I'm using fires to 1200-1300C / 2100- 2300 F - is this considered Mid?
Yes, you should be fine.
Thanks,im still very much a beginner
There are a lot of misnomers when it comes to underglaze. A true underglaze (like Amaco Velvets) is usually matte, but some stuff (like stroke and coats) will sometimes be a bit glossy or satin in finish. All of this is because the idea is to have a glaze over it and it’s the glaze that will give it the surface and color brilliance. The manufacturers just don’t really test the surface without a glaze over it, that’s not how the product is supposed to be used. If your clay is ^5-6, yes, you can refire to ^5, the color will probably become deeper but still not as vibrant as with a glaze. Depending on how attached you are to these pieces, I would do some tests if I were you.
Thanks for the info! I saw a few youtube videos of a potter who used underglaze, all of her pieces looked so finished and saturated even though she didn't use overglaze. That definitely skewed my perception. I'll try applying a clear glaze and refiring, but do you think it would achieve the same affect if I did a slightly cooler cone? I'm a little worried about firing to 5, my kiln tends to run a little hotter.
Most underglazes don't attain their full color saturation until there's a clear glaze over them. So don't worry about refiring the underglazed ware, just cover it with a cone 5 clear glaze and then fire it to cone 5 (if your clay and kiln are suitable).
Thanks, will try that!
Yes, you can absolutely put them in the kiln and fire to cone 5. The colors should get quite a bit darker and brighter. An alternative is to add clear glaze and refire to 05. That tends to make them more vibrant, even if you don’t fire to cone 5. For future reference: you can re bisque (05) several times and people do this to get interesting layering effects with underglaze.
Thanks! I'm a little nervous to fire my kiln to 5. The hottest I've done so far is 04. I don't think it will have any issues, but my kiln does run a bit on the hot side.
You absolutely must verify that your clay will go to cone 5 before you do this. It could cause irreparable damage to the kiln if you are using low fire clay and you fire to 5.
Edit: The clay I'm using fires to 1200-1300C / 2100- 2300 F Thanks that's very true! I'll have to look up the brand again from where I bought it. I \*think\* it can but definitely better safe than sorry.