emwhid324 Posted September 24, 2019 Report Share Posted September 24, 2019 I’m lost. I used Bermuda green mason stain in my porcelain clay body and it turned dark grey. I fired to cone 6. When I mixed it I used about half pound of stain to 7 pounds of a thick slip once wedged I get about 6 pounds of clay. I mix it with a mixer and then wedge it very well. I’ve never had issues before with any other colors. I used amaco clear glaze on top. I don’t believe it’s the glaze(maybe I’m wrong) because even sections I didn’t glaze are dark grey. Someone please shed some light on this and help me achieve the right color before I lose my mind Link to comment Share on other sites More sharing options...
liambesaw Posted September 24, 2019 Report Share Posted September 24, 2019 You'll need to use a zinc-free glaze over green underglaze (usually). Zinc turns chrome greens brown Link to comment Share on other sites More sharing options...
emwhid324 Posted September 24, 2019 Author Report Share Posted September 24, 2019 6 minutes ago, liambesaw said: You'll need to use a zinc-free glaze over green underglaze (usually). Zinc turns chrome greens brown Forgive me im a little confused, I only glazed one side of this, so does that mean if I used a glaze that contains zinc, even the underside(unglazed) clay body would turn this color? Link to comment Share on other sites More sharing options...
liambesaw Posted September 24, 2019 Report Share Posted September 24, 2019 25 minutes ago, emwhid324 said: Forgive me im a little confused, I only glazed one side of this, so does that mean if I used a glaze that contains zinc, even the underside(unglazed) clay body would turn this color? I don't know if that glaze contains zinc (although they do market a zinc-free version?) I also don't know if the glaze would also mess up the color of the clay, I just know that when people have an issue with a green stain or underglaze it's usually because of zinc. There is a stain compatibility chart that Mason puts out for every color so maybe reference that chart. It has very very specific slot requirements for each color. http://www.masoncolor.com/reference-guide This says you can use with or without zinc and fires to 2300 so I'm unsure. Maybe that is the color of it? It's not a chrome green, so I am gonna guess that's the fired color or maybe you were sent the wrong stuff? Link to comment Share on other sites More sharing options...
neilestrick Posted September 24, 2019 Report Share Posted September 24, 2019 You can't use the same percentage with every stain and expect success. Every color has the potential to behave completely differently than others. Some may be good at 5%, others at 20%. Your best bet to achieve positive, repeatable results is to weigh out both the stain and dry clay in specific amounts, testing the stain in increasing 3% increments. You can do little 100 gram tests and find the perfect percentage in one firing. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted September 26, 2019 Report Share Posted September 26, 2019 I have had a zinc bearing glaze next to chrome green stain bearing glaze and slip tests turn everything brown. I knew a zinc bearing glaze would mess with chrome bearing stain underneath it, but I didn't think it would mess with things next to it, or how thorough the reaction would be. It didn't just flash brown, it was all the way through. Link to comment Share on other sites More sharing options...
liambesaw Posted September 26, 2019 Report Share Posted September 26, 2019 2 minutes ago, Callie Beller Diesel said: I have had a zinc bearing glaze next to chrome green stain bearing glaze and slip tests turn everything brown. I knew a zinc bearing glaze would mess with chrome bearing stain underneath it, but I didn't think it would mess with things next to it, or how thorough the reaction would be. It didn't just flash brown, it was all the way through. Yeah but this is a vanadium pentoxide based green, which isn't supposed to react with zinc. I think in this case there's just too much/little stain and it's not quite what the color swatch was (when is it ever?). I haven't used a lot of vanadium but I do know it's normally yellow, so who knows what kind of craziness is involved with this stain. Too me it looks over saturated with stain now. Link to comment Share on other sites More sharing options...
Babs Posted September 27, 2019 Report Share Posted September 27, 2019 3 hours ago, Callie Beller Diesel said: I have had a zinc bearing glaze next to chrome green stain bearing glaze and slip tests turn everything brown. I knew a zinc bearing glaze would mess with chrome bearing stain underneath it, but I didn't think it would mess with things next to it, or how thorough the reaction would be. It didn't just flash brown, it was all the way through. Cantankerous chrome!!!! Nefarious nickel! Link to comment Share on other sites More sharing options...
liambesaw Posted September 27, 2019 Report Share Posted September 27, 2019 11 minutes ago, Babs said: Cantankerous chrome!!!! Nefarious nickel! What does nickel do? I haven't ever used it in a glaze Link to comment Share on other sites More sharing options...
Min Posted September 27, 2019 Report Share Posted September 27, 2019 @emwhid324, the March 2019 Ceramics Monthly has an article from Allison Cochran on coloured porcelain slips. I can't attach the article here but in the image below test tile E is 5% Bermuda stain. Comparing it's colour to your sample it looks like you have way more than that in yours. To save your dark batch of porcelain you could try slice it up into thin pieces, dry them out and weigh out a test amount of 100 grams. Then take some dry unstained porcelain and weigh it out and do a line blend of the two. I think that if you dilute the current batch with unstained porcelain you'll get the green back. Link to comment Share on other sites More sharing options...
liambesaw Posted September 27, 2019 Report Share Posted September 27, 2019 Welp the original post says half pound of stain to 7 pounds of thick slip, that's probably over 10% stain once the water is removed. Link to comment Share on other sites More sharing options...
Babs Posted September 27, 2019 Report Share Posted September 27, 2019 8 hours ago, liambesaw said: What does nickel do? I haven't ever used it in a glaze Whatever it wants to.test and see what you think but don't trust it. Glazenerd b prob loves it Link to comment Share on other sites More sharing options...
GEP Posted September 27, 2019 Report Share Posted September 27, 2019 12 hours ago, liambesaw said: What does nickel do? I haven't ever used it in a glaze I use a tiny bit of black nickel oxide in one of my gray glazes. It’s a neutral brown, kind of like iron oxide but without the red undertone. When combined with a tiny bit of cobalt carb, I get a pretty pale gray with a slightly blue undertone. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted September 27, 2019 Report Share Posted September 27, 2019 Arg. Sorry, the iPad died before I could edit that post properly. I didn’t read the original post as closely as I should have. @liambesaw Nickel is sort of like Worcestershire sauce: kind of gross by itself, but adds depth and interest when blended with other things. Like Mea said, it’s in the grey/olive/brown range of colours. Link to comment Share on other sites More sharing options...
Babs Posted September 27, 2019 Report Share Posted September 27, 2019 But also blues when it is / can be fickle Used for brilliant blue crystals. Can be surprisingly matte. In places.....firing schedule??? Can give a limey green depending on othrr glaze ingredients and so on. Definitely nefarious and fickle nickel. Liam look for some images and then e xpect the unexpected Link to comment Share on other sites More sharing options...
liambesaw Posted September 27, 2019 Report Share Posted September 27, 2019 Yeah crazy, looks like when you mix it with zinc it goes blue and with barium it goes pink. That's pretty neat Link to comment Share on other sites More sharing options...
Babs Posted September 27, 2019 Report Share Posted September 27, 2019 And something else a lime green maybe magnesium?? Think the crystal forming can make what is sometimes a satin/ shiny blue glaze turn matt and also the blue will " drop " out of the glaze leaving it amber shiny and splurges of matt blue...interesting if not wanted. Nice greys but.... Wish Nerd would chip in.. Link to comment Share on other sites More sharing options...
JRW Posted June 30, 2020 Report Share Posted June 30, 2020 I am having the same issue - although I’m not using glaze at all. So it must be that I used too high of a percentage of the stain. It’s interesting that with stains on other parts of the color spectrum, higher concentrations yield more vivid colors - but apparently not with light greens and blues! They just turn grey Link to comment Share on other sites More sharing options...
glazenerd Posted July 1, 2020 Report Share Posted July 1, 2020 On 9/27/2019 at 6:56 PM, Babs said: And something else a lime green maybe magnesium?? Think the crystal forming can make what is sometimes a satin/ shiny blue glaze turn matt and also the blue will " drop " out of the glaze leaving it amber shiny and splurges of matt blue...interesting if not wanted. Nice greys but.... Wish Nerd would chip in.. Babs: Been running "reaction" tests since last spring on colored porcelains. If the kaolin has higher titanium; there will be A color shirt; but those are fairly subtle. Iron bearing stains react excessively to zinc lazes. Zirconium based stains are the most stable. % of stain matters; but brown/gray result is typically a reaction. "Ody" stains are the most reliable and predictable. When I get a chance, I will snap a picture of some reactions in yellow, purple, and brown. Not been overly active lately- many posts get past me. T Link to comment Share on other sites More sharing options...
glazenerd Posted July 10, 2020 Report Share Posted July 10, 2020 Babs: Threw 6% yellow into a white stoneware (left) and porcelain (right). Even low levels of iron in white stoneware causes major color shifts- mostly headed to the brown/tan area. The stoneware (left) is half glazed, half raw @ C6. Link to comment Share on other sites More sharing options...
Babs Posted July 11, 2020 Report Share Posted July 11, 2020 Quite a difference. So test test test Link to comment Share on other sites More sharing options...
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