Gelling with Gerstley - Not a fun dance routine

by cp dunbar

May 3, 2021

My glazes have been acting ...... peculiar ,   lately.

and I read this on Facebook.  Please consider the source, so I come here for verification.

"Gerstley borate can be substituted for Frit 3134 and is half the price. Today's Gerstley borate tends to cause gelling, so about 1 drop of Darvan per 100 g recipe may be needed during mixing to get it to go through the sieve, or later after it has sat for a while and more solubles have come into solution."

So is it possible that my glazes containing current gerstley are gelling up and covering poorly due to the above?

If so, are we to watch out for this and for the Thixotropic change?    I swear my glazes used to just work.

Appreciate any input as glazes too thick or too thin is a problem.

  • up

    George Lewter

    Tony Hansen has a video on intentionally gelling a glaze, like it's a positive thing.
    https://www.youtube.com/watch?v=Ck_69eGJons 

    Linda Arbuckle has another than goes more into the rationale and differences in glazes and when to do so.
    https://www.youtube.com/watch?v=Uuh1NqLfMzw

    More from John Britt
    https://www.youtube.com/watch?v=fpQns05RdVU

    May 7, 2021

  • up

    Donna Kat

    I had a serious problem with this when they changed the final batch of Gerstley. It had never happened before. It only became an issue though when members would add water to the glaze, thinking it was too thick. Then of course the glaze would still go on thick but would dry up like a lake bed forming large cracks. Once I was able to get people to weigh the glaze and use a deflocculant when needed things were fine. IMO weighing a specified volume of glaze is critical to keeping application consistent. 

    May 26, 2021