Ozon Posted November 25, 2016 Report Share Posted November 25, 2016 Hi, I would like to ask a question regarding reduction firing of porcelain. After (some of) my firings there seems to be a thin layer on top of my porcelain objects, which is not very white, more slightly yellowish grey. It very subtle though. But I realised when I sand it for a while it goes off, though this is quite labour intense work. I would like to understand better why this happens. Does someone know if it would be possible to avoid this? I have heard earlier that some ingredients also fired in the kiln might affect the porcelain colour. My reduction firing, was reduction from 950 to 1200 and fired till 1250. In about and around 15 hours. Any tips or information would be very welcome. As I would love to understand the reduction firing process better. Thank you so much! Link to comment Share on other sites More sharing options...
Chilly Posted November 25, 2016 Report Share Posted November 25, 2016 Do you have photos? They will help the team to advise you. Link to comment Share on other sites More sharing options...
Ozon Posted November 25, 2016 Author Report Share Posted November 25, 2016 Thank you for the reaction, but it won't be visible on the pictures. As it shows white, but ones you looked close with a loop you can see it only. I'm thinking it might be a chemical reaction but not sur Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 25, 2016 Report Share Posted November 25, 2016 I think it is probably from the gases in the reduction possibly fuming or scumming from the glazes. Marcia Link to comment Share on other sites More sharing options...
glazenerd Posted November 25, 2016 Report Share Posted November 25, 2016 The only possible chemical reaction would be titanium (brookite) but low on the list of possibles. Nerd Link to comment Share on other sites More sharing options...
Mark C. Posted November 25, 2016 Report Share Posted November 25, 2016 When you say on top of the clay is this work fired raw or bisque first? with no glaze on it in final fire?a few more details would help and a photo of a piece even though we cannot see it may help. You also mention you can only see the dust with a loop-In 43 years I never have used my slide loop to view pottery? Are you sanding bisque ware -raw clay or fired wares??? More info is needed Link to comment Share on other sites More sharing options...
neilestrick Posted November 25, 2016 Report Share Posted November 25, 2016 Much more info needed. Is the entire pot raw clay, or are there glazes in use? Is the discoloration on the entire piece or just in certain areas? Other glazed pieces in the kiln? Link to comment Share on other sites More sharing options...
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