Jump to content


Photo

using two company glazes...toxic ?


  • Please log in to reply
7 replies to this topic

#1 Fish Lady

Fish Lady

    Newbie

  • Members
  • Pip
  • 4 posts

Posted 01 April 2013 - 12:13 PM

If I use a matt glaze from company "A" and then add a clear gloss from company "B" will it cause the finish to become toxic or will it stay food safe?

#2 bciskepottery

bciskepottery

    Advanced Member

  • Members
  • PipPipPip
  • 1,255 posts

Posted 01 April 2013 - 12:55 PM

Any time you overlap two different glazes . . . you create a new, third glaze. And, depending on the contents of the two glazes, you could end up with an unstable/nondurgable glaze that leeches a coloring oxide, etc. Doesn't matter if the glazes were made by two different companies or the same company. Putting a "safe" clear over a "problem" glaze will not automatically make the resulting glaze safe . . . you need to test it.

#3 Fish Lady

Fish Lady

    Newbie

  • Members
  • Pip
  • 4 posts

Posted 01 April 2013 - 01:14 PM

Any time you overlap two different glazes . . . you create a new, third glaze. And, depending on the contents of the two glazes, you could end up with an unstable/nondurgable glaze that leeches a coloring oxide, etc. Doesn't matter if the glazes were made by two different companies or the same company. Putting a "safe" clear over a "problem" glaze will not automatically make the resulting glaze safe . . . you need to test it.



How do I test to see if it has become toxic?

#4 bciskepottery

bciskepottery

    Advanced Member

  • Members
  • PipPipPip
  • 1,255 posts

Posted 01 April 2013 - 01:46 PM


Any time you overlap two different glazes . . . you create a new, third glaze. And, depending on the contents of the two glazes, you could end up with an unstable/nondurgable glaze that leeches a coloring oxide, etc. Doesn't matter if the glazes were made by two different companies or the same company. Putting a "safe" clear over a "problem" glaze will not automatically make the resulting glaze safe . . . you need to test it.



How do I test to see if it has become toxic?



Here's a start: http://digitalfire.c...achable_12.html

Also, consider picking up a copy of John Hesselberth/Ron Roy's "Mastering Cone 6 Glazes". The bible for making durable, stable glazes and how to test them at home.

#5 Fish Lady

Fish Lady

    Newbie

  • Members
  • Pip
  • 4 posts

Posted 01 April 2013 - 04:18 PM



Any time you overlap two different glazes . . . you create a new, third glaze. And, depending on the contents of the two glazes, you could end up with an unstable/nondurgable glaze that leeches a coloring oxide, etc. Doesn't matter if the glazes were made by two different companies or the same company. Putting a "safe" clear over a "problem" glaze will not automatically make the resulting glaze safe . . . you need to test it.



How do I test to see if it has become toxic?



Here's a start: http://digitalfire.c...achable_12.html

Also, consider picking up a copy of John Hesselberth/Ron Roy's "Mastering Cone 6 Glazes". The bible for making durable, stable glazes and how to test them at home.



Thank you... I currently have one dish with a lemon and another with vinegar.

#6 JBaymore

JBaymore

    Moderator

  • Moderators
  • 2,460 posts
  • LocationWilton, NH USA

Posted 01 April 2013 - 04:36 PM

Thank you... I currently have one dish with a lemon and another with vinegar.


Note that those are only "rule in" tests not "rule out".

If they fail that test, you have no need to run a lab test. If they PASS that test, it does NOT say that it will not leach components. Only a standard acetic acid leach test will do that. (lab testing)

Note that if the glaze does not contain any toxics, then there is no need to test. It might be "bad" glass...... and deteriorate in visual character over time and use..... but it will not harm anyone.

best,

.......................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#7 Iforgot

Iforgot

    Advanced Member

  • Members
  • PipPipPip
  • 155 posts
  • LocationColorado

Posted 05 April 2013 - 10:35 PM

What color is the matte glaze from "A" company?



Darrel
Derek VonDrehle

Raku, Pit fired, Majolica, and Stoneware ceramic artisit

#8 Fish Lady

Fish Lady

    Newbie

  • Members
  • Pip
  • 4 posts

Posted 06 April 2013 - 05:03 PM

Alabaster




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users