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mason stains aren't steadfast, whats missing?


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#1 kokopelle2012

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Posted 26 May 2013 - 10:21 PM

Hi,


I've been making terra-cotta pots for my plants. The pots i paint with mason stains, then fire. I fire to cones between 03 and 5. What i'm finding is that once these pots have been fired, many of the colors i've applied tend to rub off. I dont want to use an over glaze, its very important to me that the surface remain flat/matt free of sealants. Other times the mason stains turn to dark olive greens and browns and yellows, like rotten bruises. (this is after they've come in contact with water). Has anyone worked with this, come across these problems, or have suggestions on proper mason stain mixtures?


I'm typically measuring by eye, water, pigment, some flint, some light bodied clays and some of the base clay used for the pot thats being painted. (i have an ingredients list at the studio if thats needed)
i've attached 2 pictures, one is of a pot fresh out of the kiln, the other is one thats gotten wet a few times.
what are your thoughts!!!???


-isaac

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#2 justanassembler

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Posted 26 May 2013 - 11:53 PM

Hi,
I've been making terra-cotta pots for my plants. The pots i paint with mason stains, then fire. I fire to cones between 03 and 5. What i'm finding is that once these pots have been fired, many of the colors i've applied tend to rub off. I dont want to use an over glaze, its very important to me that the surface remain flat/matt free of sealants. Other times the mason stains turn to dark olive greens and browns and yellows, like rotten bruises. (this is after they've come in contact with water). Has anyone worked with this, come across these problems, or have suggestions on proper mason stain mixtures?
I'm typically measuring by eye, water, pigment, some flint, some light bodied clays and some of the base clay used for the pot thats being painted. (i have an ingredients list at the studio if thats needed)
i've attached 2 pictures, one is of a pot fresh out of the kiln, the other is one thats gotten wet a few times.
what are your thoughts!!!???
-isaac


If your surfaces are rubbing off, they havent been fired onto the pots to begin with.... Mason stains really arent meant to be used alone, and simply adding silica to a low-fire wash wont flux it enough to stick...

#3 OffCenter

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Posted 27 May 2013 - 07:55 AM

Hi,
I've been making terra-cotta pots for my plants. The pots i paint with mason stains, then fire. I fire to cones between 03 and 5. What i'm finding is that once these pots have been fired, many of the colors i've applied tend to rub off. I dont want to use an over glaze, its very important to me that the surface remain flat/matt free of sealants. Other times the mason stains turn to dark olive greens and browns and yellows, like rotten bruises. (this is after they've come in contact with water). Has anyone worked with this, come across these problems, or have suggestions on proper mason stain mixtures?
I'm typically measuring by eye, water, pigment, some flint, some light bodied clays and some of the base clay used for the pot thats being painted. (i have an ingredients list at the studio if thats needed)
i've attached 2 pictures, one is of a pot fresh out of the kiln, the other is one thats gotten wet a few times.
what are your thoughts!!!???
-isaac


You aren't using the Mason Stains correctly. There are many ways to use them but just painting them on with some silica and clay and firing to a random cone between 03 and 5 is not one of them. Test first.

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#4 Marcia Selsor

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Posted 27 May 2013 - 12:54 PM

A good recipe for an underglaze stain at that temperature is 1/3 stain, 1/3 epk, 1/3 frit 3110

You need a binder and a flux. the epk and frit provide that.

Marcia

#5 Chris Campbell

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Posted 27 May 2013 - 01:34 PM

You would be 100% happier and get nice consistent results if you used underglazes instead of random mason stain mixtures. Amaco velvets work wonderfully and keep a nice velvet like surface. They are not expensive and would save you money in the long run because you would have less failures.

Chris Campbell
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#6 oldlady

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Posted 27 May 2013 - 04:49 PM

You would be 100% happier and get nice consistent results if you used underglazes instead of random mason stain mixtures. Amaco velvets work wonderfully and keep a nice velvet like surface. They are not expensive and would save you money in the long run because you would have less failures.





thank you for saying what i would have. but you are much more polite.
"putting you down does not raise me up."

#7 mregecko

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Posted 29 May 2013 - 12:06 PM

Pretty much already covered, but just going to agree.

Mason stains are usually just colorants. Painting them onto the surface of unglazed clay, especially low fire (e.g. more porous) clay, means that they have nothing to "adhere" them to the clay body. They're essentially just dust on top of the clay and a lot of them will wash off.

You would either need to mix a frit with them (as mentioned, I think 3110 is good around this temperature range) which will flux them to the clay body...

Or -- what I would do -- buy a pre-mixed underglaze that is specced for your temperature range. They come with fluxes already in them and are formulated for staying power and vibrancy.

Hope some of this has helped!




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