Clay darker than expected

[Lara-Poppyseed]

Hello!

I recently purchased some Laguna Speckled Buff (WC-403) and have been throwing some pieces on the wheel. I have been looking for a perfect honey brown/light tan speckled clay and finally came across this one. Anyway, I made and fired some pieces with a Cone 6 cone in the kiln sitter and everything turned out kind of burned (?) looking and darker than I was expecting. I fired some more pieces but this time put a Cone 5 bar in the kiln sitter and got almost the same result My glazes also aren't showing up as well. Does anyone have any ideas of why it is coming out like this or have any advice? 

Thanks a bunch!  

[oldlady]

that is similar to the clay i started with.  i was working with colored slip carved into geometric shapes around thrown pieces.   

your clay looks lovely to me, i like the toasty color of the basic clay.   what disappoints you about the glaze?   do you want an opaque covering to contrast with the clay?   are you making your own glaze or buying it?

[Roberta12]

my speckled buff looks just like yours.  The picture from the Laguna site may not be as accurate as what we get in reality.  I bisque to 04 and glaze at 6.  

 

Roberta

[Mark C.]

Just keep in mind those fired Laguna samples are fast fired and cooled in a small kiln. They color is usually not quite what the tiles look like. Closew but not exactly. I think your sample looks great by the way .

[Callie Beller Diesel]

Clays with a lot of iron or other impurities will bleed through the glaze like that. It looks like I would expect it to. You may find you need to add a thicker layer of glaze, or somehow block the speckles from bleeding through. To do that, you could add a little opacifier to your glaze recipe, or use a white slip under the areas you want glazed. 

If you want a less dense speckle effect but otherwise liked working with this clay, try cutting it with another white stoneware. You’ll have to wedge via cut and slam, unless Laguna sells dry bags of their clay bodies that you can just add water to.

For what it’s worth, the darker speckle is nice, I think.

 

[Min]

3 hours ago, Lara-Poppyseed said:

fired some pieces with a Cone 6 cone in the kiln sitter and everything turned out kind of burned (?) looking and darker than I was expecting. I fired some more pieces but this time put a Cone 5 bar in the kiln sitter and got almost the same result

As a side note, Laguna lists the absorption for that clay at 3% at cone 5. Since it looks like you are making functional pots I'ld stick with cone 6 to try and get that absorption figure down a bit otherwise you can have leaky pots (with or without glaze). I'ld strongly suggest using some witness cones and go by what they are telling you than just using the bar in the sitter. I'ld also run your own absorption tests since the data from clay companies comes with some wiggle room insofar as absorption figures. (info on how to that here if you need it, fairly straightforward)

[Babs]

You may have to use an opacifier in your glazes if speckle isn't what you want of your glazes.

[Lara-Poppyseed]

3 hours ago, oldlady said:

that is similar to the clay i started with.  i was working with colored slip carved into geometric shapes around thrown pieces.   

your clay looks lovely to me, i like the toasty color of the basic clay.   what disappoints you about the glaze?   do you want an opaque covering to contrast with the clay?   are you making your own glaze or buying it?

Thank you! I am used to my glazes showing up brightly and not translucent-ish. I like the speckled coming through but I’d like them to stay strong still. I am only buying commercial glazes as this point, just moved everything to my home studio at this point.

[Lara-Poppyseed]

1 hour ago, Callie Beller Diesel said:

Clays with a lot of iron or other impurities will bleed through the glaze like that. It looks like I would expect it to. You may find you need to add a thicker layer of glaze, or somehow block the speckles from bleeding through. To do that, you could add a little opacifier to your glaze recipe, or use a white slip under the areas you want glazed. 

If you want a less dense speckle effect but otherwise liked working with this clay, try cutting it with another white stoneware. You’ll have to wedge via cut and slam, unless Laguna sells dry bags of their clay bodies that you can just add water to.

For what it’s worth, the darker speckle is nice, I think.

 

I was recommended this clay by another potter. Her work looks so much lighter to me, and less dense speckled. Maybe I can try your idea of wedging in some white stoneware! Thank you for your ideas!

[Mark C.]

All your photos  of that clay look very much alike to me.None seem that much lighter or darker-your 1st photo is just a tad darker but as far as clay varies I really do not see a huge difference .

[fergusonjeff]

This is the same clay I use for most of my cone 6 work.  I usually mix it about 50/50 with other cone 6 porcelain or stoneware.  Laguna makes another speckled clay you might try, but it is sometimes harder to get.  I thin the number is 608.  I think it trows much better than 403 but if anything it has even more speckle.  I think 608 is more brown compared to 403 being more yellow.