Jump to content

Recommended Posts

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

71295235_2481448888558178_1803060058641137664_o.jpg

Share this post


Link to post
Share on other sites
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?
 

Share this post


Link to post
Share on other sites
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?

 

Edited by liambesaw

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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. 

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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!

Share this post


Link to post
Share on other sites

@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.

image.png.a27cbd371f24882fa2d5e8e0f6b2d8b7.png

Share this post


Link to post
Share on other sites
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. 

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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..

Edited by Babs

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.