issues with pink Mason Stains

[Studio314]

I work with about 8-10% Mason Stains to color my porcelain  "Audrey Blackman" with it. that works wonderfully. Except for the pinks/pinks, the hue disappears the hotter I fire. Test at Cone 04, 1, and 1, 6. Here's what it says on the Mason Stains website:

WHY DO I NOT GET GOOD PINKS OR CRIMSONS AT CONE 06/2/5/10, ETC.?

Mason's chrome-tin pink series, 6000 to 6006, are stable from Cone 06 (normal "low" temperature) to Cone 12 (normal "high" temperature). This type of pigment requires the correct glaze chemistry, in all temperature ranges, in order to maximize the "color value". High calcium content is the most important. The zinc and magnesia levels must be low to zero and boron should not be too high. These rules do not necessarily apply when "fast-firing" techniques are used. Also, these pigments need an oxidizing atmosphere throughout the firing cycle.

I can't quite figure this out. Do I need to mix calcium into my porcelain clay? I've also already written to support twice, but can't get a response.

Maybe someone of you can explain to me what I can do better.

Thanks

Bjoern

[PeterH]

In case it's any help there is an analysis in

Porcelain body "Audrey Blackman“  https://glazy.org/materials/58805

[Min]

Issue is any chrome + tin stain needs a fairly high amount of calcium in the base glaze plus it helps if the alumina is on the low side. If you were to add calcium to your clay it would increase the fluxing of the body, by it's nature clay needs to contain a lot of alumina, there is no getting around this. Better choice for pink is to use an alumina + manganese pink stain such as Mason 6020 . Other option is to use one of the cadmium inclusion stains which are also suitable to use as a claybody stain. These are expensive. Going forward have a look at the Mason Reference Guide, any of the stains with a number 1 as a reference at the end of the row containing the stain you are looking at means it's suitable for use as a body stain. You will still have to test your glazes over the stained claybodies. Reference numbers explained at the top of the guide page.

Screenshot of the pinks and reds section of the Mason Reference Guide below. See how none of the chrome tin stains in the upper part of the chart are suitable as a body stain but all the cadmium inclusion reds are. (for pink you can use a red stain at a lower percentage)

Welcome to the forum.

[Callie Beller Diesel]

I’ve been finding that magnesium also kills pink at cone six in glazes. I’ve also found that pink and yellow stains also benefit from small quantities of fluxes like strontium, barium or lithium in a glaze. These are impractical to use to adjust a clay body however.

What I did find in some of my tests in adding stain to a white stoneware slip was that Mason Violet (6304) does turn a far more pink than purple colour, and is not violet at all. The bottom colour on the plant pot here is it. I want to say it was probably 10% stain in Plainsman m370 clay. It’s not porcelain by a long shot.

[Babs]

Miggt be less exp. to create a pink slip and apply to yoour pots . @Callie Beller Diesel does this beautifully.

[liambesaw]

Also remember that zinc will bleach out red/pink/purples.

[oldlady]

i have used several of the mason pink stains for years to make slip.   no funny elaborate "recipe" for slip, just my clay body with water added.  and pink stain.   that is all.   works fine, i will look up particular mason numbers in my tests if you are really interested.    my clay is a white stoneware.   who knows, maybe they will work with your porcelain.

[Studio314]

On 3/19/2021 at 11:39 PM, oldlady said:

i have used several of the mason pink stains for years to make slip.   no funny elaborate "recipe" for slip, just my clay body with water added.  and pink stain.   that is all.   works fine, i will look up particular mason numbers in my tests if you are really interested.    my clay is a white stoneware.   who knows, maybe they will work with your porcelain.

Hello Old Lady, 

That sounds interesting. It would be awesome if you would share your Mason numbers with me. I would love to try them.

[Studio314]

Thank you everyone. I think I have to try different stains and different porcelains  and clays as well. 
"update" I researched a little more and maybe Mason Stain 6020 (alumina Pink) could work because it's a Body Stain. That leads me to another problem. This is only to order in the US and not for instance at Scarva in Britain.  

 

[Min]

I'ld email Scarva if that's where you order from and ask them if any of their pink stains are manganese alumina stains or any of the reds cadmium inclusion stains. If they aren't sure then ask where to find the Safety Data Sheets for all their pinks, including their nano particle stains, they will list the oxides used in the stains. Just from a quick look at Scarva's website it looks like they do carry Mason 6088, it's a cadmium inclusion stain, the Safety Data Sheet for it is here. Look at section 3 of it. Mason 6021 is available and a cadmium inclusion stain also. 

[Studio314]

Thanks Min, for this detailed information. I already got in touch with them if they are able to supply Mason 6020. If not I will raise your question aubout the manganese alumina stains if they are not already refer to it. I am not that deep into reading data sheets but as far as I understand searching for cadmium inclusion inside the stains makes the trick right?

 

 

[Min]

1 hour ago, Studio314 said:

I am not that deep into reading data sheets but as far as I understand searching for cadmium inclusion inside the stains makes the trick right?

Cadmium Inclusion Stains are made from zirconium silicate with cadmium sulfoselenide. If the stains are ball-milled or undergo other mechanical treatments they break down and cadmium is released. Cadmium is far more dangerous than lead as a toxin. This cannot be under stressed. I don't know what you are making with the coloured clay, if you are making pots for food I would have a sample or two tested for cadmium release. I don't know where in Europe you can get this done but ask Scarva about it, they should know. If you are just making small amounts for jewellery or some such thing the cadmium stains would probably be fine. Do some reading on inclusion stains, sometimes called encapsulated or inclusion pigments, one place to start is here. Note the maximum firing temperature/cone and don't exceed that either. If you are not comfortable with using them for your situation/needs then don't.

Much better choice for pots for food would be a manganese + alumina pink stain then you don't have to worry about cadmium plus it will be far less expensive.

[Studio314]

15 hours ago, Min said:

If you are not comfortable with using them for your situation/needs then don't.

Hmm, doesn't sound like my type of stuff I would like to go for. But I think the manganese + alumina pink stain is the one that definitely suits my needs. 

Thank you

[Jeff Longtin]

I have been experimenting with "pink" as well. I find Mason Stain 6020 (Body Stain) works great as a body stain in porcelain clay. (8%) I found it not to be a good glaze stain. I found Mason Stain Shell Pink, 6000, to be a great glaze stain but a terrible body stain. (8% as well, with 3% zircopax) The stains 6000 thru 6006 make great glaze stains. They are not bright reds, like the Encapsulated stains, 6021/6088/6097, but there are much easier and much safer to use.

[oldlady]

bjoern, sorry that i did not find this sooner.   i have mixed many colors of slip and have tests to show the fired results, cone 6, in an album found under my avatar.  it is the last one on page 1 under albums.   i just looked at it and se that the last photo of the pink stains has somehow become dark so you can hardly see the colors.   

will get the test tiles and info again and send them here, (if i can make the photos small enough).

[Studio314]

Hey old lady,

 

thank you so much for your effort. And I already can see it from the pictures in your album.