AndreaB Posted April 18, 2016 Report Share Posted April 18, 2016 Morning everyone hope you all had a good, productive weekend. I've just fired a glaze run and am hoping you can help. I used mason black underglaze to colour ball clay slip. Applied to just thrown items, drying each layer before applying next. A total of three layers. I didn't glaze over the "black" half of the pot, wanting a distinct contrast to a white glaze on the rest of the pot. The result was a matt grey section. Is this because I didn't dip in transparent glaze? Or should I have used an oxide rather than the underglaze. I throw with a stoneware that fires to a light grey. Any suggestions would be greatly appreciated. Thanks and have a great day. Link to comment Share on other sites More sharing options...
MatthewV Posted April 18, 2016 Report Share Posted April 18, 2016 I would use a kaolin instead of ball clay--should have brighter colors. About 10% dry stain, 90% kaolin is a good starting point. If you started with a liquid underglaze (~30% stain I believe), it may be possible to thin it out to about 3 times the volume. A clear glaze would also help, but mostly just in the vibrancy. Sometimes I will make clear very very thin to retain more of the natural feel with just a slight gloss. The black slips I have worked with were black enough after the bisque firing. Link to comment Share on other sites More sharing options...
Celia UK Posted April 18, 2016 Report Share Posted April 18, 2016 I've had similar colour from white clay slip + black stain. I'll watch the replies with interest! Link to comment Share on other sites More sharing options...
Chris Campbell Posted April 18, 2016 Report Share Posted April 18, 2016 Which black stain did you use and what % of stain did you use? Link to comment Share on other sites More sharing options...
Chilly Posted April 18, 2016 Report Share Posted April 18, 2016 My brain says that mixing black underglaze with anything less than black will give you grey! Or am I missing something? Link to comment Share on other sites More sharing options...
Min Posted April 18, 2016 Report Share Posted April 18, 2016 +1 for what Chilly said. You have just diluted the underglaze with the slip. Use the underglaze as is or thinned down with a bit of water and try a test with one, two and three coats. Link to comment Share on other sites More sharing options...
neilestrick Posted April 18, 2016 Report Share Posted April 18, 2016 Underglazes are meant to be used as is. If you want to color a slip, use stain. Link to comment Share on other sites More sharing options...
AndreaB Posted April 18, 2016 Author Report Share Posted April 18, 2016 Thank you all. Didn't really think things through properly. I've a few more pots that I have done the same way. I'll use underglaze on them. Link to comment Share on other sites More sharing options...
oldlady Posted April 23, 2016 Report Share Posted April 23, 2016 andrea, you did not mention the crawling of the white glaze. do you have a way to prevent that or do you need help with it, too? Link to comment Share on other sites More sharing options...
AndreaB Posted April 23, 2016 Author Report Share Posted April 23, 2016 andrea, you did not mention the crawling of the white glaze. do you have a way to prevent that or do you need help with it, too? Thanks, I think it is just a too thick an application of the glaze. My pouring out has been a problem. I take too long to pour out. I've had a little problem with my left hand shaking while I pour with right hand and then taking too long to pour out. I'll switch to pouring with left hand and emptying with right. Although it's a fault in my process I quite like the texture that it brought out. But saying that these items are not going to be marked for sale. Which black stain did you use and what % of stain did you use? I didn't use stain. I just added underglaze to slip. I had done some other pots the same way. I've now covered the applied slip with underglaze and bisqued them and they look much better. These were thrown with a white groged clay and I'll glaze with transparent, so hopefully I'll achieve the result I was looking for. Having said that do you think I should glaze the black sections? I was trying to go for a "natural" textured black as opposed to a shiny one. Link to comment Share on other sites More sharing options...
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