How bad can efflorescence of soluble salts on fired ceramic be?

Saturday 12th October 2013

Like this! This insight-live.com/glossary/88">terra cotta clay matures to good strength around 1950F. Notice how the salts have concentrated on the outer and most visible surface, the more vitreous this fires the worse it looks! The piece was dried upside down so of course, all the water had to escape through that route. A complicating factor is how handling of the piece at the leather hard stage has made it even more unsightly. This problem is common in many terra cotta materials but can also surface in others. Barium carbonate can be used to precipitate the salts inside the clay matrix so they do not come to the surface on drying. There is good news: Solubles salt deposition can actually be much worse than you see here.

Pages that reference this post in the Digitalfire Reference Library:

The Use of Barium in Clay Bodies, Soluble Salts, Terra Cotta, Sulfates, Efflorescence

This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.