Glazing on a Dark Clay Body

[MudNug]

Hey guys! I'm looking to make a sink basin for my bathroom in the upcoming months. I want to use Standard Ceramics 266 Dark Brown Clay with a turquoise/seafoam glaze on the interior while leaving the exterior bare. Attached is an idea of what I would like to do. I have never used a dark clay before, so I don't have experience to work off of and can't make test tiles until it is safe to use the studio again. Would coating the inside of the clay with a white underglaze cause the blue glaze to stand out more? Does anyone have a good glaze suggestion that stands out and reacts well to this clay? Or does anyone have other suggestions for completing this project whether it be clay type, glaze, helpful tips, etc.? Thanks for all the help!!

[liambesaw]

2 hours ago, MudNug said:

Hey guys! I'm looking to make a sink basin for my bathroom in the upcoming months. I want to use Standard Ceramics 266 Dark Brown Clay with a turquoise/seafoam glaze on the interior while leaving the exterior bare. Attached is an idea of what I would like to do. I have never used a dark clay before, so I don't have experience to work off of and can't make test tiles until it is safe to use the studio again. Would coating the inside of the clay with a white underglaze cause the blue glaze to stand out more? Does anyone have a good glaze suggestion that stands out and reacts well to this clay? Or does anyone have other suggestions for completing this project whether it be clay type, glaze, helpful tips, etc.? Thanks for all the help!!

Alternatively you could use the clay body you normally use and just put an iron oxide wash on the outside to stain it brown.

[Min]

4 hours ago, MudNug said:

Would coating the inside of the clay with a white underglaze cause the blue glaze to stand out more?

Yes, or you could use a white slip while the clay is at the  leatherhard stage, getting it on as soon as possible. If you do a search on the forum for Standard 266 you'll come across quite a few posts where people have had bloating and/or glaze issues with it. It's a high iron and manganese body, needs a slow well vented bisque firing. 

4 hours ago, MudNug said:

I want to use Standard Ceramics 266 Dark Brown Clay with a turquoise/seafoam glaze on the interior while leaving the exterior bare.

When only one side of a pot is glazed it's really important to have a well fitting glaze or the force the glaze puts on the pot can lead to the body cracking. I'ld suggest really testing your glaze(s) with test cylinders before committing your sink. Make up some cylinders with the Standard 266, use the slip or underglaze on the inside. After you bisque fire them glaze them with a heavy layer of your glaze(s) only on the inside and fire. Freeze the cylinders overnight then put them in the sink and pour boiling water into them. If they crack then you need to alter the glaze to fit the clay. Make up the cylinders to about the same thickness as you'll be making the sink. Thicker ware is more likely to be okay than very thin ware.

Hi and welcome to the forum.

 

[MudNug]

3 hours ago, liambesaw said:

Alternatively you could use the clay body you normally use and just put an iron oxide wash on the outside to stain it brown.

That's a great idea! I've only worked with a red iron oxide once before on Brown 112. It gave a very rustic look, however it was pretty transparent. That could've been because I applied a thin coat. Do you recommend a certain type of iron oxide that would give the color and effect I am looking for on a white clay body? Thank you so so much!

[MudNug]

1 hour ago, Min said:

Yes, or you could use a white slip while the clay is at the  leatherhard stage, getting it on as soon as possible. If you do a search on the forum for Standard 266 you'll come across quite a few posts where people have had bloating and/or glaze issues with it. It's a high iron and manganese body, needs a slow well vented bisque firing. 

When only one side of a pot is glazed it's really important to have a well fitting glaze or the force the glaze puts on the pot can lead to the body cracking. I'ld suggest really testing your glaze(s) with test cylinders before committing your sink. Make up some cylinders with the Standard 266, use the slip or underglaze on the inside. After you bisque fire them glaze them with a heavy layer of your glaze(s) only on the inside and fire. Freeze the cylinders overnight then put them in the sink and pour boiling water into them. If they crack then you need to alter the glaze to fit the clay. Make up the cylinders to about the same thickness as you'll be making the sink. Thicker ware is more likely to be okay than very thin ware.

Hi and welcome to the forum.

 

Thank you so much for welcoming me! I'm still learning how everything works that's for sure :)

Good to know that using an underglaze could be an option. I will definitely be making test tiles before I commit if the dark clay is the route I take!! I will also be looking through the Standard 266 forum you suggested. I'm loving having a place to hear from people that have hands-on experience with things that I haven't had a chance to work with yet!

[Sorcery]

I used the 266 and 710 with grog and swore the 710 was smoother. I'd use it for a sink. Maybe with half 547 even for more grog.

The 266 is very prone to warping, but the recommended firing temperature has been moved to 4. I've tested it vitreous at 5/6, you should be fine at 4.

This is a pic of Amaco's tourmaline on 266.

It definitely doesn't have the iron content that enhances blues, the 547 does.

I might be able to dig up more photos.

Sorce

 

[Callie Beller Diesel]

Red Art and Alberta slip both make nice iron washes that get a bit glossy, sort of engobe-like if you want to go the dark slip over light clay route. If you want to stick with the dark clay, some floating blues respond better over iron bearing clays than they do over white ones, notably the bases from the Digitalfire site.