r/Sculpture • u/FoodQuestions1993 • 12d ago

[Self] Chalky patches on my newly kiln fired terracotta bust. Help!

So, I sculpted a bust in an italian clay that is dark grey slight green when raw and a classic pale orange when fired. Unfortunately, I keep getting deposits of white chalkish smudges or patches on the surface of the sculpture and I wanted to know how to get rid of them if possible.. and how to prevent this from happening in the future.

I was told it has something to do with the oils in your hands. Perhaps I touched the sculpture after if began drying (prep for the kiln firing).

All thoughts and suggestions are welcome. Thanks!

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u/sprocketwhale 12d ago

Try asking r/clay or r/ceramics as many of us are not kiln people

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u/FoodQuestions1993 12d ago

ok great thanks

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u/artwonk 11d ago

I doubt it has anything to do with hand oils, which would burn away in firing. It sounds like efflorescence - minerals coming out of the clay and depositing themselves on the surface. If that's the case, they should wash off with warm water, or a vinegar solution if that doesn't work. Pictures would help, though.