quampegan Posted May 12, 2010 Report Share Posted May 12, 2010 Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! Link to comment Share on other sites More sharing options...
Denice Posted May 17, 2010 Report Share Posted May 17, 2010 Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! Are you firing with gas or electric and is there a reason your working at cone 10. The higher you fire the fewer variations you have in oxides or stains. Since you are new to clay you might consider working at cone 6. You can purchase underglazes premixed to experiment with, they still burn out some at cone 6 but nothing like cone 10, you can usually get a color chart with them that shows the intensity of the under glaze at different temperatures. I work with a Majolica glaze at cone 1, I want my colors to be fairly bright but also have the pieces vitrified for outdoor use. Denice (Wichita, KS) Link to comment Share on other sites More sharing options...
hansen Posted May 17, 2010 Report Share Posted May 17, 2010 Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! It almost sounds like you are trying to imitate Chinese Blue on White. Which is cobalt oxide or cobalt carbonate tempered with a little bit of other oxides to soften the color, I can't remember the exact formula, suspended in a little clay mixed with water, to make a paint, use a fine camel hair brush with fairly long bristles to get fine lines, paint over the cone 10+porcelain in the greenware or bisque ware stage, the glaze fire with clear cone 10+ porcelain type glaze. Using white porcelaineous stoneware shouldn't be too much of a problem if your brushstrokes are bigger than that. Other colors might be introduced the same way. Basically you paint with pure oxides, even still, some of them burn out. The old Chinese pots, some of them had cobalt decoration and then copper red also. Be careful firing with the cobalt - it will jump in the kilns atmosphere to other pots. You can make a wash of pure oxides too, and spray it on with an atomizer. Be careful, some oxides are toxic. You can get them through suppliersh a n s e n Link to comment Share on other sites More sharing options...
Foster Posted August 16, 2010 Report Share Posted August 16, 2010 So if you are firing your Majolica glaze to cone 1, how are you getting your pieces vitrified? Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! Are you firing with gas or electric and is there a reason your working at cone 10. The higher you fire the fewer variations you have in oxides or stains. Since you are new to clay you might consider working at cone 6. You can purchase underglazes premixed to experiment with, they still burn out some at cone 6 but nothing like cone 10, you can usually get a color chart with them that shows the intensity of the under glaze at different temperatures. I work with a Majolica glaze at cone 1, I want my colors to be fairly bright but also have the pieces vitrified for outdoor use. Denice (Wichita, KS) Link to comment Share on other sites More sharing options...
Denice Posted August 16, 2010 Report Share Posted August 16, 2010 So if you are firing your Majolica glaze to cone 1, how are you getting your pieces vitrified? Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! Are you firing with gas or electric and is there a reason your working at cone 10. The higher you fire the fewer variations you have in oxides or stains. Since you are new to clay you might consider working at cone 6. You can purchase underglazes premixed to experiment with, they still burn out some at cone 6 but nothing like cone 10, you can usually get a color chart with them that shows the intensity of the under glaze at different temperatures. I work with a Majolica glaze at cone 1, I want my colors to be fairly bright but also have the pieces vitrified for outdoor use. Denice (Wichita, KS) Hi this is Denice To answer your question about the vitrification, I am using a Laguna low fire red terra cotta. I did all of the freeze test I could find and made a talavera tile mural and laid it out in the Kansas winter. The vertical installation the tile wouldn't get that much snow and ice covering it like the mural on the ground. I bisque to Cone 02, I have to pour the glaze on the tiles and let them dry, cone 02 is nearly vitrified for that clay. If your going to apply the glaze in a different manner you may have to bisque to a lower cone. I bisque at 02 with this particular clay because it eliminates almost all of the white impurity dots that show up in the majolica glaze surface. I tested clays and glazes for nearly a year before I was satisfied with the results. If you don,t have a test kiln, get one they are a time and energy saver. Denice Wichita,KS Link to comment Share on other sites More sharing options...
Foster Posted August 17, 2010 Report Share Posted August 17, 2010 So if you are firing your Majolica glaze to cone 1, how are you getting your pieces vitrified? Hello...I have been trying to effect a Majolica-like decoration on white stoneware with a clear over-glaze at cone 10. I have been using cobalt carbonate & cobalt oxide hoping to be able to vary the shade of blue. There isn't any difference in the shading and it appears that carbonate is crazing through the clear over glaze. I am fairly new to pottery...and need some advice. Would I be better off trying to use Mason stains? Ultimately I would like to add other colors to my designs...but right now I am focusing on the blues. Thanks for any direction you can offer! Are you firing with gas or electric and is there a reason your working at cone 10. The higher you fire the fewer variations you have in oxides or stains. Since you are new to clay you might consider working at cone 6. You can purchase underglazes premixed to experiment with, they still burn out some at cone 6 but nothing like cone 10, you can usually get a color chart with them that shows the intensity of the under glaze at different temperatures. I work with a Majolica glaze at cone 1, I want my colors to be fairly bright but also have the pieces vitrified for outdoor use. Denice (Wichita, KS) Hi this is Denice To answer your question about the vitrification, I am using a Laguna low fire red terra cotta. I did all of the freeze test I could find and made a talavera tile mural and laid it out in the Kansas winter. The vertical installation the tile wouldn't get that much snow and ice covering it like the mural on the ground. I bisque to Cone 02, I have to pour the glaze on the tiles and let them dry, cone 02 is nearly vitrified for that clay. If your going to apply the glaze in a different manner you may have to bisque to a lower cone. I bisque at 02 with this particular clay because it eliminates almost all of the white impurity dots that show up in the majolica glaze surface. I tested clays and glazes for nearly a year before I was satisfied with the results. If you don,t have a test kiln, get one they are a time and energy saver. Denice Wichita,KS Hi Denise, thank you so much! --Foster Link to comment Share on other sites More sharing options...
MadMudder Posted August 23, 2010 Report Share Posted August 23, 2010 I work with a Majolica glaze at cone 1, I want my colors to be fairly bright but also have the pieces vitrified for outdoor use. Denice (Wichita, KS) Is this truly possible? Can you really get a clay that vitrifies at cone 1 for outdoor use? Please FESS up!! Sincerely, MadMudder Link to comment Share on other sites More sharing options...
quampegan Posted September 21, 2010 Author Report Share Posted September 21, 2010 Thank-you all for your responses. I was pre-occupied the last month with mother-issues. I have continued to experiment and did mix my own cobalt oxide glazes. I am getting more variation on the blues and feel that I have some control. I even started to make my own brushes to get the strokes that I needed. I tried bits of different Mason stains and I am using an over or on-glaze technique with clear as the base. The yellows have not been great. I have not yet tried them as an underglaze...which is my next plan of experimentation. At the moment I am still trying to get better at thinner walls and centering larger amounts of clay. The reason for the Cone 10 is 2-fold: that's my teacher's kiln and I really want long-term dishwasher surviving wares. I understood that the higher the temp of firing...the stronger the pot? In general, how do cone 6 wares fare in the dishwasher over time? Thanks for all of your suggestions and help. ~B Link to comment Share on other sites More sharing options...
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