Testing (mostly) Amaco underglazes in a soda kiln

Written By Emily Murphy
A sampling of Amaco underglazes in a soda firing.
A sampling of Amaco underglazes in a soda firing.

I love data! In all of my years of teaching soda firing at Lillstreet Art Center and at Northern Clay Center, I always have students asking questions about what underglazes might work in the soda kiln. There is often a desire to get a touch of color that is best achieved with an underglaze. But hard to know where to start! And some of them can be pricey (hello reds!). So I did some crowdsourcing with my NCC classes to test the Amaco underglazes that we collectively owned. Most are the line of Amaco Velvet underglazes (that's what the V is for). But there are a few other lines (DV and SS) that are discontinued. But jars are still floating around out there so we tested the ones we had. Some of the Designer Velvet underglazes are gorgeous! Firing underglazes in reduction, at cone 10 is not a typical use. So you can't get the information you might be looking for out of the maker's test tiles. These test tiles have been invaluable to my students. And I am hoping that this post, sharing them, will help many more!

a guide to Emily Murphy's underglaze test tiles in the soda kiln.
I made this little guide to the test tiles that I made so you can see how each third of the tiles were created. Isn't it cute? I tried to fit as much information on each tile as possible. Although you know with soda firings, the range of possibilities is huge. These tiles are more of a guide to tell you what might be possible.
Please note: the Smooth Orange Flashing Slip recipe is included after the test tiles!

blacks and grays

  • Velour Black V 370
  • Jet Black V 361
  • Pearl Gray V 356
  • Fossil Gray DV 3328
  • Dark Gray V 357

whites

  • White V 360
  • Ivory Beige V 301

reds

  • Radiant Red V 388
  • Tulip Red
  • Red V 382
  • Light Red V 383

pinks

  • Navaho Pink DV 3316
  • Medium Pink V 317
  • Light Pink V 316
  • Rose V 318
  • Rosy Mauve V 371

oranges

  • zinnia orange SS 205
  • Real Orange V 384
  • Orange V 350
  • Marigold Orange SS 203
  • Royal Peach V 374
  • Peach V 315
  • Snapdragon SS 202

yellows

  • Yellow V 308
  • Intense Yellow V 391
  • Deep Yellow V 309
  • Deep Yellow V 309
  • Daffodil Yellow SS 204

greens

  • Leaf Green V 354
  • Light Green V 345
  • Hunter Green V 376
  • Dark Green V 353
  • Shadow Green V 355
  • Cactus Green DV 3359
  • Mint Green V 372
  • Chartreuse V 343
  • Desert Grass DV 3372
  • Turquoise Stone DV 3327

blues

  • Turquoise Blue
  • Teal Blue V 332
  • Royal Blue V 336
  • Medium Blue V 326
  • Electric Blue V 386

purples

  • Purple V 322
  • Lilac V 321
  • Lavender V 320

browns

  • Red Brown V 313
  • Medium Brown V 373
  • Chocolate Brown V 314
  • Terra Cotta V 303
  • Tan V 310
  • Fawn V 369
  • Cinnamon V 385
  • Sandstorm DV 3369
Recipe for Smooth Orange Flashing Slip for the soda kiln
Here is the recipe for Smooth Orange Slip used on the test tiles under the striped area. There is some wiggle room on what clay bodies you use this on, if it is applied to bisque or leather hard clay. But generally, it is best on leather hard clay. And must be fired in an atmospheric kiln to flash. Otherwise it will just be white!

Oval vase by: Emily Murphy (me!)
photograph by: Guy Nichols

I am happy to be back to blogging! Thanks for reading and sharing!

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Emily Murphy
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