Looking for an underglaze that does not flux. Cone 5-6.

[Linnea56]

It will be used on Standard 266 Dark Brown clay  to paint into carved recesses, and NOT glazed over with clear. I’m looking for color to stand out against the deep brown of the vitrified clay. Like rich rust, teal, green….

 Possibly for white stoneware as well, but right now, it’s the dark brown carved clay project that have numerous bisqued pieces waiting for an answer.

 The only ones I have used are Amaco Velvets (only Velour Black) and Speedball white.  

 I know there are other brands out there, but I don’t know which ones flux.

 I don’t necessarily need it to be matte finish like the Amaco Velvets: just that I am not going to paint clear into every little carving to make it shiny. I usually like matte or satin anyway.

 The studio where I fire my work also has glazes for low-fire “paint your own pottery”. I tested those in the colors I liked, and all of them bubbled to some extent or the colors were dull. Other people have used them, but maybe not on this clay body, and always with a high fire clear on top.  

 The Speedball white was for a different  idea: I was trying to create a white base to use certain glaze colors that don’t show well on the 266 Dark Brown, or that blister on this clay; to have part of the piece unglazed dark brown, and the glazed area over the white base. The Speedball White fluxed under a glaze on top and came up through it: a truly ugly, spotty effect. I’ve moved on to using a white slip instead for the portion I plan to glaze: though I can’t really carve properly into it. If I could find the right product for this second concept, that would be great too.

 Thanks for your help.

[Bill Kielb]

Hmm, not sure any of it “fluxed” actually so I am curious what you mean by that. You might find glazes such as stroke and coat give you the look you want including the gloss and a durable finish opaque enough to use over the dark clay painted into the carvings. Glazes wiped off remaining in the carvings and reliefs also often provide a certain look similar to underglaze in the accents. Post a picture or two of success or failure with what is objectionable and you will likely get plenty of specific ideas here. Don’t forget to include your desired firing range.

our experience with the interaction of some underglazes and overglazes has been when the underglaze is refractory it can make the overglaze bubble and under fire. Counter intuitive but often just an incomplete melt in the area of the combination of the two. Thick application of underglaze often magnifies this issue. The fix is often a more fluid overglaze which is just counter intuitive but can happen so worth mentioning I believe.

We had to develop specific matte and gloss clears to melt completely over heavy underglazes so we could decorate as desired and pick the finish desired.

Here is the matte and tests on various underglazes and claybodies https://glazy.org/recipes/19734

[Hulk]

Hi Linnea!

I'm filling chatter marks with underglaze (Speedball) and glaze.
Glaze is easier to work with; I'll use underglaze where I want the particular color.
I like the contrast, also, glaze sometimes is prone to crawling out if the chatter marks aren't wetted all the way to the bottom.
So far, not seeing any problems with Speedball underglazes* under any of the glazes I work with, nor any we used at the local JC ceramic lab.
I'm brushing the glaze/underglaze into the chatter marks with a wet brush. With a wet brush, the underglaze floats a bit, hence less build up where I don't want it, and it follows the water into the marks. I'm following with a sponge to wipe away all except the what's filled in the marks.

For carving, I'm using red slip** applied with a brush just after trimming - while the clay is still leather hard.
The ware will soften a bit, due to the water in the slip. After a bit of drying time, I've tried carving with a small loop tool and some home made tools. It's fun.
Perhaps give that another try? The thickness of the slip likely matters; I'm not applying a thick layer at all. A smooth well behaved slip would likely carve better than something with sand/bits in it...

*I'm also curious what you meant by "fluxed" - what problems are you having? Are you applying thick/thick-ish layers of underglaze?
**Blended red stoneware chunks with water, ran through a screen to remove sand and whatnot, then allowed to dry to the consistency I'm looking for - brushable.

Here there's some carving through red slip, also filled chatter marks.

[Min]

@Linnea56, could you post a picture of what isn't working? All underglazes are going to contain flux, are some of them getting eaten up or changing colour or ?

12 hours ago, Linnea56 said:

I’ve moved on to using a white slip instead for the portion I plan to glaze: though I can’t really carve properly into it.

Just to clarify, for this second project you are putting white slip on dark clay and carving at leatherhard but it's not working?

[Roberta12]

@Linnea56  I have to agree with @Bill Kielb about the Stroke and Coat.  I bought a few small bottles last year to use on earrings and ornaments.  I have been pleased with the results at 04 and 6.  It could be worked into carved texture and would be fine at 5/6.  I do not use Standard clay but I have been using  New Mexico Chocolate  which fires dark brown and had success with Amaco white underglaze, Amaco Turquoise, Amaco Flame Orange, Deep Yellow, and Chartreuse.    They contrast quite nicely on the dark brown clay.  They hold their color well, glazed or unglazed.  If you need a bulletproof slip recipe, let me know.  I have one that has worked well by itself or with stains for colorant.  By itself it is very white, final firing.  

Yes, pics would help.  Curious about the fluxing.  

Roberta

[Linnea56]

2 hours ago, Hulk said:

Hi Linnea!

I'm filling chatter marks with underglaze (Speedball) and glaze.
Glaze is easier to work with; I'll use underglaze where I want the particular color.
I like the contrast, also, glaze sometimes is prone to crawling out if the chatter marks aren't wetted all the way to the bottom.
So far, not seeing any problems with Speedball underglazes* under any of the glazes I work with, nor any we used at the local JC ceramic lab.
I'm brushing the glaze/underglaze into the chatter marks with a wet brush. With a wet brush, the underglaze floats a bit, hence less build up where I don't want it, and it follows the water into the marks. I'm following with a sponge to wipe away all except the what's filled in the marks.

For carving, I'm using red slip** applied with a brush just after trimming - while the clay is still leather hard.
The ware will soften a bit, due to the water in the slip. After a bit of drying time, I've tried carving with a small loop tool and some home made tools. It's fun.
Perhaps give that another try? The thickness of the slip likely matters; I'm not applying a thick layer at all. A smooth well behaved slip would likely carve better than something with sand/bits in it...

*I'm also curious what you meant by "fluxed" - what problems are you having? Are you applying thick/thick-ish layers of underglaze?
**Blended red stoneware bits with water, ran through a screen to remove sand and bits, then allowed to dry to the consistency I'm looking for - brushable.

Here there's some carving through red slip, also filled chatter marks.

If I want to just carve into the slip and not into the underlying clay (which does not show glaze colors well), I have to lay on multiple coats and then I have brushstrokes and an uneven surface. Thin enough to not show brushstrokes, it takes multiple coats. Another problem is that the iron in the brown clay seems to seep up into the white slip and stain it brown. It's not reliquifying the brown clay, the surface took fine when it is applied. This happens over time before it gets dry enough to carve, and also while the piece is drying. I'll take a photo of a sample I made that shows this well. 

 

I only used the white Speedball once. I disliked the effect enough that I never used it again. Though I could fire it again - which idea I got on this site, reading through underglaze threads - before applying the glaze, wouldn't that make the surface too vitrified to accept the glaze in the end?   

[Linnea56]

32 minutes ago, Roberta12 said:

@Linnea56  I have to agree with @Bill Kielb about the Stroke and Coat.  I bought a few small bottles last year to use on earrings and ornaments.  I have been pleased with the results at 04 and 6.  It could be worked into carved texture and would be fine at 5/6.  I do not use Standard clay but I have been using  New Mexico Chocolate  which fires dark brown and had success with Amaco white underglaze, Amaco Turquoise, Amaco Flame Orange, Deep Yellow, and Chartreuse.    They contrast quite nicely on the dark brown clay.  They hold their color well, glazed or unglazed.  If you need a bulletproof slip recipe, let me know.  I have one that has worked well by itself or with stains for colorant.  By itself it is very white, final firing.  

Yes, pics would help.  Curious about the fluxing.  

Roberta

Roberta, which Amaco underglazes are you using? Velvets or LUGs? If they show up well on dark brown, that's what I want. Are they matte when not covered with a clear? 

I don't really understand the functions or applications for them having 2 different lines of underglazes. I'm guessing one line might be more translucent for watercolor type applications, but I can't find info for that on their site. I'd want opaque. 

Another question for you: I was looking through the reds and oranges for both lines last night. All the warm tones end up looking rather pinkish on the sample chips when uncoated. Have you noticed that? I understand why (the matte surface scatters light differently), but I don't want any pink tones. Thanks. 

[Hulk]

"...wouldn't that make the surface too vitrified to accept the glaze in the end?"

Good question, idk, having always applied underglaze to bisque, then glazed over it and glaze fired.

[neilestrick]

Most traditional underglazes will remain matte or semi-matte after firing, but some colors do melt out more than others, even within the same line of underglazes. For instance, Speedball 'Red' and 'Royal Blue' melt and get rough/bubbly at cone 6. Every other Speedball color I've tested (and I've tested most of them) work just fine at cone 6, including all of the other reds and blues. Speedball underglazes take glaze better if you bisque fire the underglaze before glazing, if you're using a dipping glaze. With brushing glazes it doesn't matter.

3 hours ago, Linnea56 said:

If I want to just carve into the slip and not into the underlying clay (which does not show glaze colors well), I have to lay on multiple coats and then I have brushstrokes and an uneven surface. Thin enough to not show brushstrokes, it takes multiple coats. Another problem is that the iron in the brown clay seems to seep up into the white slip and stain it brown. It's not reliquifying the brown clay, the surface took fine when it is applied. This happens over time before it gets dry enough to carve, and also while the piece is drying. I'll take a photo of a sample I made that shows this well. 

266 is a crazy clay body. It does things to glazes and underglazes that don't happen with other bodies, so it may just take some testing to find colors that work for you. It may also require a layer of white slip under the underglaze to keep the clay from affecting the color. It's a big ask to expect a body that dark to not affect the glazes on it. Make a white slip and add some zircopax to opacify it. If you really don't want brush strokes, then multiple thin coats are the way to go unless you spray them on. It's just the nature of the materials. The same would be true with slips. You'll also get more even coverage by applying multiple thin coats. Most underglazes are too thick in the bottle, so thin them down with water.

Stroke'N'Coat are glossy, and require 3 coats for opacity, so maybe not what you want.

 

[oldlady]

linnea, could you please explain how you "carve" into an underglaze?   my understanding of carving is that there is depth involved.   what depth do you see in a layer of underglaze?   and why use a dark clay if you are going to cover it with a white slip???

[Roberta12]

6 hours ago, Linnea56 said:

Roberta, which Amaco underglazes are you using? Velvets or LUGs? If they show up well on dark brown, that's what I want. Are they matte when not covered with a clear? 

I don't really understand the functions or applications for them having 2 different lines of underglazes. I'm guessing one line might be more translucent for watercolor type applications, but I can't find info for that on their site. I'd want opaque. 

Another question for you: I was looking through the reds and oranges for both lines last night. All the warm tones end up looking rather pinkish on the sample chips when uncoated. Have you noticed that? I understand why (the matte surface scatters light differently), but I don't want any pink tones. Thanks. 

@Linnea56 Velvets.  They have been opaque for me.  I use them on Dark brown clay, speckly brown clay and porcelain.  I am sort of in love with the Flame Orange. No, not pink.  I have some pics of those colors on dark brown clay and speckled buff.   I may be teaching some small workshops and I am going to try Speedball underglazes.  Lots of thumbs up from people who use them.  I really do not know the difference between LUGs and Velvets.  I wanted a more opaque, saturated color so I have always used the velvets.  In the photo of the little dishes, the orange is flame orange, there is radiant red, turquoise, deep yellow, chartreuse.  And the navy color is Duncan Concepts.  On the planter the ug's are chartreuse and turquoise.  Everything is velvet.

[Bill Kielb]

1 hour ago, Roberta12 said:

On the planter the ug's are chartreuse and turquoise.  Everything is velvet.

Nice work, nice decoration!

[Linnea56]

3 hours ago, oldlady said:

linnea, could you please explain how you "carve" into an underglaze?   my understanding of carving is that there is depth involved.   what depth do you see in a layer of underglaze?   and why use a dark clay if you are going to cover it with a white slip???

Here's an example of what I am trying to do, but with greater precision: the top glazed portion is over white, and the bottom is the dark clay. If I were to attempt to glaze the dark clay, I couldn't get these colors. I think this dark clay is just beautiful unglazed, but I don't want the whole piece unglazed. This is a bit of a goopy result, but it was good to start with. 

[Linnea56]

2 hours ago, Roberta12 said:

@Linnea56 Velvets.  They have been opaque for me.  I use them on Dark brown clay, speckly brown clay and porcelain.  I am sort of in love with the Flame Orange. No, not pink.  I have some pics of those colors on dark brown clay and speckled buff.   I may be teaching some small workshops and I am going to try Speedball underglazes.  Lots of thumbs up from people who use them.  I really do not know the difference between LUGs and Velvets.  I wanted a more opaque, saturated color so I have always used the velvets.  In the photo of the little dishes, the orange is flame orange, there is radiant red, turquoise, deep yellow, chartreuse.  And the navy color is Duncan Concepts.  On the planter the ug's are chartreuse and turquoise.  Everything is velvet.

Are all the underglazes covered with a clear glaze? Since I don't want a gloss coating, but want them to stay matte, the pinkish look may be impossible to avoid. 

[Linnea56]

5 hours ago, neilestrick said:

Speedball underglazes take glaze better if you bisque fire the underglaze before glazing, if you're using a dipping glaze. With brushing glazes it doesn't matter.

Ah. That would explain my messy ugly result in my first attempt to use the Speedball white. I DID use a dipping glaze. The studio manager  told me the Speedball White had fluxed under the Albany Slip brown I dipped over it. He has since left, so I couldn't ask more.

I will test again : 1) using a brushing glaze over the Speedball White.  2) bisque firing the underglaze on first, then dipping. Question: should I bisque first, apply the underglaze, then bisque again? Or apply the underglaze to greenware, then bisque? Thanks. 

 

4 hours ago, oldlady said:

linnea, could you please explain how you "carve" into an underglaze?   my understanding of carving is that there is depth involved.   what depth do you see in a layer of underglaze?   and why use a dark clay if you are going to cover it with a white slip???

The intent is not to carve into the underglaze, but to PAINT the underglaze into the carved or stamped designs. 

Here is a photo of a test I did. I want to paint INTO just the recesses. 

"why use a dark clay if you are going to cover it with a white slip???:" so I can get a brighter color glazing over the white slip, and still exploit the color of the dark clay on a portion. 

[Linnea56]

6 hours ago, neilestrick said:

Most traditional underglazes will remain matte or semi-matte after firing, but some colors do melt out more than others, even within the same line of underglazes. For instance, Speedball 'Red' and 'Royal Blue' melt and get rough/bubbly at cone 6. Every other Speedball color I've tested (and I've tested most of them) work just fine at cone 6, including all of the other reds and blues. Speedball underglazes take glaze better if you bisque fire the underglaze before glazing, if you're using a dipping glaze. With brushing glazes it doesn't matter.

266 is a crazy clay body. It does things to glazes and underglazes that don't happen with other bodies, so it may just take some testing to find colors that work for you. It may also require a layer of white slip under the underglaze to keep the clay from affecting the color. It's a big ask to expect a body that dark to not affect the glazes on it. Make a white slip and add some zircopax to opacify it. If you really don't want brush strokes, then multiple thin coats are the way to go unless you spray them on. It's just the nature of the materials. The same would be true with slips. You'll also get more even coverage by applying multiple thin coats. Most underglazes are too thick in the bottle, so thin them down with water.

Stroke'N'Coat are glossy, and require 3 coats for opacity, so maybe not what you want.

 

Here is a photo of the weird effect I got with white slip over 266.  It wasn't the dark clay dissolving into the slip, it's like it rose up through it. It's like tarnish! (Metals are my original medium). 

I found it like this the next morning after it was all dry.  This has not been fired.

After this, I tried making some pieces in white stoneware, then coating the white with 266 slip. But it's really hard to get it even. Even if it looks perfect after bisque, patchy streaks show up after glaze firing. And since the 266 portion is meant to be unglazed, every streak shows. 

 

[Linnea56]

11 hours ago, Min said:

could you post a picture of what isn't working? All underglazes are going to contain flux, are some of them getting eaten up or changing colour or ?

here is a photo of the white Speedball underglaze "Fluxing" (or something) under the top glaze, which is dipped Albany Slip Brown. Patchy, splotchy.... 

[Linnea56]

I'm adding this test chip photo. The left spot is Speedball White underglaze, the right is white Amaco Velvet underglaze. The speedball is definitely shiny, but it HAS been glaze fired. I ordered the Speedball because is is MUCH cheaper than the velvets (like a fraction of): and if I'm going to cover a large part of a pot and then glaze over it, it would be far more cost effective.  If I could get that to work,  rather than the white slip, it would be GREAT. 

For painting INTO the carved or stamped decoration, I definitely want matte, or at least not shinier than the clay: so the shiny Speedball will not work. It looks like the Amaco Velvets are the way to go for that part; unless there are other suitable underglazes that are matte. 

So, 2 different applications for underglaze; but related. 

 

[Bill Kielb]

Some thoughts Looking at this clay body, I wouldn’t fire it beyond cone 5, try some tests at that temp. I also would try and make sure this is bisqued thoroughly to 04 and double check with standard if they suggest a specific long bisque.

I also would not expect a particular finish from any underglaze but if one finishes suitably after testing then that would be a candidate to test its durability.

Underglazes generally do not fully melt so using it as a final surface on wares for food service is not something I would do either as many of the colorants are encapsulated and intended not to melt. It is sold as an underglaze so I think there is a reasonable expectation that an overglaze will be used to encapsulate it.

I also would definitely try stroke and coat (a low fire glaze that goes to cone 6), just in case you liked the result and think it would stand a chance of fully melting making those areas glazed likely more durable for food service.

I think I would always use a quality liner glaze, fully melted without defects with this body especially for areas that touch food, liquids, peoples mouths etc…..

just some thoughts.

[PeterH]

1 hour ago, Bill Kielb said:

Some thoughts Looking at this clay body, I wouldn’t fire it beyond cone 5, try some tests at that temp

For the record the standard site lists it as c/4-5  https://standardceramic.com/products/266-dark-brown-clay

... although it is listed as cone 4-6 elsewhere - e.g. https://www.theceramicshop.com/product/92/dark-brown-266/

[Bill Kielb]

5 hours ago, PeterH said:

For the record the standard site lists it as c/4-5

My thought: I would take Standard at their word since it’s their clay and test and or maybe call them just to be sure.

[neilestrick]

We use a fair amount of 266 in my studio. It shouldn't be fired above cone 5 or your risk bloating.

13 hours ago, Linnea56 said:

here is a photo of the white Speedball underglaze "Fluxing" (or something) under the top glaze, which is dipped Albany Slip Brown. Patchy, splotchy.... 

I'm not really sure what you're seeing here because I don't know what the glaze is supposed to look like. Are you just trying to get something between the glaze and the black clay so the clay doesn't affect the glaze color? If you're looking for a white that doesn't move, then a slip would be the best way to go, and it would be a lot cheaper than underglazes. Underglazes can move if the glaze on top of them moves. I do that on purpose with my work, letting the fine black lines bleed out to give a little more interest to the surface. If you don't want them to move at all, then you need a stiff glaze on top.

[Roberta12]

14 hours ago, Linnea56 said:

Are all the underglazes covered with a clear glaze? Since I don't want a gloss coating, but want them to stay matte, the pinkish look may be impossible to avoid. 

Yes, in those 2 photos everything is glazed.  The small (bug dishes) dishes were brushed, and the planter was dipped. I used a clear that I mix.    However, I have not gotten any pink on unglazed clay.  In fact, most of the underglaze pinks fade out for me.  The best way for me to get a coral or pinkish color is to blend Radiant Red with Salmon.  As everyone tells us, test test test.  It looks like you have been doing that.  Your clay and firing will be completely different from mine or anyone else's.  But even unglazed, my reds and oranges do not fire pink.  I am firing to cone 5/6.  And, the photos I posted also had the underglaze applied to greenware, then bisqued, then glazed.  I have used underglaze on bisque ware but I have been trying to speed up my glaze process by doing the surface decoration at the greenware stage then all I have to do is apply the clear glaze after bisque firing.  

[Linnea56]

11 hours ago, Bill Kielb said:

Some thoughts Looking at this clay body, I wouldn’t fire it beyond cone 5, try some tests at that temp. I also would try and make sure this is bisqued thoroughly to 04 and double check with standard if they suggest a specific long bisque.

I also would not expect a particular finish from any underglaze but if one finishes suitably after testing then that would be a candidate to test its durability.

Underglazes generally do not fully melt so using it as a final surface on wares for food service is not something I would do either as many of the colorants are encapsulated and intended not to melt. It is sold as an underglaze so I think there is a reasonable expectation that an overglaze will be used to encapsulate it.

I also would definitely try stroke and coat (a low fire glaze that goes to cone 6), just in case you liked the result and think it would stand a chance of fully melting making those areas glazed likely more durable for food service.

The underglaze decoration I want to do is only for exteriors, to enhance the appearance of the bare dark brown 266. Anything inside will be fully glazed.   As I said before, it's been a challenge finding glazes that show up on 266. 

If 266 does not like to go to cone 6, that would explain the suboptimal results with blistering or pebbly surface some classmates have had using some Mayco glazes that need closer to cone 6. I thought maybe using a white slip would help on those, but maybe not? I thought perhaps it was iron interacting with the glaze, not the clay itself. This is useful to know, thanks.  

I bought 2 Mayco glazes, because Amaco was always out; then ran into the person who had been having problems. I have tests tiles with them on white stoneware and 266  being fired today (Sunday).  I'll find out what cone they were fired to. 

I'll ask the firing person about this for the future. He was planning on having some loads closer to 6 and some closer to 5, once kilns are fixed.  It seems like one of three is always down.  I can always just plan on sticking to lower firing glazes, cone 5  on 266. Keep the Mayco for white stoneware. 

[Linnea56]

1 hour ago, neilestrick said:

Are you just trying to get something between the glaze and the black clay so the clay doesn't affect the glaze color? 

Yes. For the pieces where I am covering part with glaze, I am trying to make the glaze show up more like it does on white stoneware. 

So slip might be the answer for future pieces, as long as I can plan the application in advance and get a smoother surface that I can carve or stamp through. I might try lightly burnishing next time before carving or stamping.

I do have a backlog of labor-intensive pieces that are bisqued with no slip on them, though. With the studio shut down for a year, I was able to get pieces bisqued to take home, where they wait for me to have an answer.