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Paint Firing Caused 'bloom' On Glass

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#1 Gilcrux



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Posted 13 May 2018 - 12:45 PM

Hello folks


I fired some painted glass last week using thinfire on my kiln shelves - the paint was Reusche black on various green cathedral glass and brown Tatra,  I took the glass up to 650 Deg Celcius.


Thought everything was looking good before the firing and was careful about handling the glass to avoid fingermarks etc, but after opening the kiln, discovered most of the glass had a 'bloom' on the surface which can be seen.  


I haven't had this before and wondered if it was due to the kilnpaper, my firing, the glass not being clean enough or just bad luck.


Has anyone else had similar problems using kiln paper or have suggestions so I can avoid this again?


Thank you!



#2 Knight


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Posted 14 May 2018 - 09:15 AM

By "bloom" do you mean devitrification? 

Everything that you did should have produced a more positive outcome. I have gotten into the habit of crashing my kiln and racing it back to oven temp around 500 deg F, this keeps that "iffy" temp range of 700-1100 where the devitrification is most likely to happen out of the equation. When my kiln hits 1225F I turn it off and crack it to vent it down quickly. The kiln I have is very small and built to withstand this, not all kilns are the same! 

#3 Gilcrux



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Posted 15 May 2018 - 02:31 PM

Hello ,  yes a bit like devit.  Really disappointing and irritating!  I think perhaps I just need to be more mindful of how clean the glass is pre-firing and perhaps adjust my temperatures slightly.  Thanks for responding :)

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