Mason Stains in Porcelain Slip

[Jeff Longtin]

As this just came out of the kiln I thought I would share: these are cone 6 porcelain casting slip test tiles.  (Coasters cut in half.) To which I've added various amounts of Mason Stains: Vivid Blue, Delphinium Blue and Zircopax. 

So that I can apply the glaze thinly I add stain to the clay, as well, to add to the opacity of the glaze. (I find that glaze drips/overlaps, become less evident if the clay body matches the glaze.)

Rather than use a total amount of 6% Vivid Blue, in the glaze, on top of a very white porcelain body, I added 3% to the body and 3% to the glaze. 

Its been a tedious process but its really interesting to see how the stains interact with the clay and glaze.

[Min]

Interesting approach, makes a lot of sense to do it like this. Slip casting seems the perfect vehicle. 

[Jeff Longtin]

I certainly didn't think glazing the pieces would be so complicated. I thought about spraying the glazes, for uniformity, but that too has complications.

Here's another photo showing more color tests.  Each of these test tiles represents a Mason Stain that no longer is being produced. The far left tile features Robins Egg 6 with Delphinium 2. The next tile is Delphinium 1.6 with Zircopax 8.4. The intense blue is Delphinium at 3.5% and Zirco 2. The purple tile is an attempt at the Violet and Amethyst. (6001 Pink with Vivid Blue)

The two yellowish tiles represent Peach. (6001 with Praesadium Yellow.)  

Note:  Many years ago Mason sold over 200 different stains. Today they sell 80-90. (guessing) They decided the world probably doesn't need to 10 different types of purple. What they did, instead, is to post the recipes for those discontinued colors on their website. ("Archived Formulas") Its tedious buying several stains, to produce one, but it does lead to some surprising color variations.

Edited January 8, 2023 by Jeff Longtin

[kswan]

@Jeff Longtin Those are nice! Have you tried also just clear glazing over the stained clay body? I wonder if that would intensify the stain color in the porcelain.  I took a class where a student was trying to match the clay body and glaze color, and he discovered that just clear over it made a nice effect. 

I look at all the lovely possible mason stain colors and feel frustrated when they don't turn out right. Purple is still giving me headaches when trying to make my own underglazes. They keep disappearing when it's not applied thick enough, but I don't want it so thick. I can't remember which website it was, but I bought some of the remaining discontinued colors they had. They're sitting in a box waiting for me to try again to make them work. My plan this year is to mix up successful underglazes and glazes. Gotta keep working on that chemistry (not my strong suit).  I don't use it in my clay body though, just painted on the surface. 

Kathy

[Babs]

Are you usng body stains or glaze stain ,or are body stains a thing of the past?

[oldlady]

i have been using colored slips with mason stains for many years.  my clay is white, highwater's little loafers.   i have colored some of the clay as well but prefer to use slip made of my clay and distilled water plus stain or a carbonate.    i am lucky enough to have quantities of some colors, cerulean blue is my favorite color and if it runs out, t i know it is made from a recipe using 2 other stains.   staining slip is so simple and the strong colors come out so well that you might try it.  sieving the slip first and after the stain is mixed in makes a reliable color.  saving slurry gives a great foundation for the slips.  pansy purple works well.

purchasing underglaze has not proved valuable to me.  the bottles dry up before i can use the entire 2 ounces.   i do use  some underglaze colors to make slip, brilliant yellow and some others.

my albums show a number of tests of slips.  

Edited January 8, 2023 by oldlady

[Bam2015]

9 hours ago, Jeff Longtin said:

Note:  Many years ago Mason sold over 200 different stains. Today they sell 80-90. (guessing) They decided the world probably doesn't need to 10 different types of purple. What they did, instead, is to post the recipes for those discontinued colors on their website. ("Archived Formulas") Its tedious buying several stains, to produce one, but it does lead to some surprising color variations.

 

Jeff, thank you for that info about discontinued Mason stain formulas. I had no idea that this info was available. I like a couple of stains that have been discontinued and now I can recreate them without the guess work.

Betty 

[Jeff Longtin]

Kathy,

I appreciate that. Yes, I have tried clear glaze. My experience is that the clear glaze is slightly cloudy and not the clear effect I was hoping for. 

Purple: Mason used to sell 8-10 "purple" variations. Not so anymore. Tin Violet is a really intense purple but owing to the tin its terribly expensive. You could also try Pansy Purple.  That has a good purple color and is not as expensive as Tin Violet.

[Jeff Longtin]

Babs,

Yes, I've been using Body Stains as well.  Alumina Pink 6020 is used in lots of discontinued formulas.  It also does serve well as a body stain. (In a glossy glaze it produces nice matte effects.)

[Min]

2 hours ago, Jeff Longtin said:

Tin Violet is a really intense purple but owing to the tin its terribly expensive. You could also try Pansy Purple.

Cd inclusion stain Violet from US Pigments is running at $30 a pound, might be another option. It's about half the price of Mason's 6304 Tin Violet.

[grackle]

I have had mixed luck with stains, and wonder if it is because i use too much of the powder in relation to water?  sometimes I get thick spots.  or maybe it is just the application?  are stains typically mixed with something else?

[Min]

@grackle, are you using the stains + water as a wash? Typically when stains are used as a wash they are mixed with a frit or gerstley borate to help them bond with the clay during firing. Some people use 50:50 stain and gerstley borate, others use up to 50% frit (3124 or 3134 typically) and some kaolin to help suspension along with the stain. Some stains are more refractory than others so there isn't a hard and fast rule for proportions. Chrome green stains are quite refractory.

[grackle]

Okay, so after mixing the stain with a frit or GB, I then add water, and then my stain will hopefully not sink right to the bottom, but remain in suspension longer and brush on (i usually brush on for design purposes) more evenly.  That would be wonderful!!  And the refractory part means that the color of some stains works more accurately than others?  In terms of heat?

[Min]

7 hours ago, grackle said:

Okay, so after mixing the stain with a frit or GB, I then add water, and then my stain will hopefully not sink right to the bottom, but remain in suspension longer and brush on (i usually brush on for design purposes) more evenly.  That would be wonderful!!  And the refractory part means that the color of some stains works more accurately than others?  In terms of heat?

Stain + frit + kaolin (epk is fine)  or stain + gerstley borate will both suspend better than stain alone or with just frit. Still need to stir it while using it but it won't sink so quickly.

 Refractory means the substance doesn't melt very well by itself. Example would be  the chrome green stains tend to be refractory, that is to say the surface will be dry and resist melting either with or without a covering glaze. Chrome green stains need more "melter", either a frit or gerstley borate in this example to bond with the underlying clay. Some other stains, like cobalt blues are more "melty" and won't need as much frit or gerstley borate. Rough rule of thumb would be 1/3 stain, 1/3 frit and 1/3 kaolin OR 1/2 stain and 1/2 gerstley borate, measured in parts of volume not weight. Like everything else try a tiny bit on a test piece before committing real work to it. If the result is too dry then increase the frit or gerstley borate, if it's too melted then decrease those. If the colour is too intense (cobalt blues probably will be) then decrease the stain.

 

Edited March 20, 2023 by Min
clarity

[Callie Beller Diesel]

Just a word on brushability: if you’re using gerstley borate, the mixture will brush quite easily the first day, or until it dries out. GB will keep your mix in suspension quite well, and is a preferable vehicle from an application standpoint. BUT I found small partially dried quantities can be difficult to reconstitute. Also, GB can affect some stains’ colour response. Worth doing some testing before you commit to a precious piece.

If you’re using kaolin and frit, it’ll settle out a little more rapidly, but it’s easier to reconstitute the next day. If you’re mixing more than a few tablespoons at a time like I was, you might want to add a little epsom salt solution.

[High Bridge Pottery]

In my recent glaze tests I have found 20% kaolin 80% frit will suspend really well for at least a few weeks to a month whereas 10% kaolin 90% frit will be trying to hard pan in about 12 hours.

[grackle]

thank you all so much.  I am in a glazing stage at the moment, and have several pieces that I can use for testing --small bowls that i make to fill out edges in the kiln (if they turn out well, all the better!)  This way, I can see how different methods/recipes work with my clay.

I especially appreciate the clarification on "refractory"--I looked it up, but Your definition, Min, was , for me, more easily understood!!

Now just need to keep really good notes.

[grackle]

another question about using stains.  in the past, i have glazed a white bisque piece with a clear glaze, and then applied the stain designs.  would it work the other way around.  i know with under-glaze, i do the under glaze first and then the clear.  since i am ready to try that, will just go ahead and do 2 one way and 2 the other!