GEP Posted March 15, 2013 Report Share Posted March 15, 2013 One of the glazes at the studio where I teach is behaving very strangely. The sludge that settles on the bottom is gelatinous and sticky. It's very difficult to stir the sticky sludge back into the glaze. Even when the glaze appears to have been stirred thoroughly, it will separate when fired. It will look like the normal glaze, but with blotchy patches of clear glaze here and there. The recipe contains Veegum, which is the only ingredient that I am not familiar with, but I do know it helps with suspension. I'm wondering if this is causing the sticky situation. If so, can this batch be saved? Or, does anyone have suggestions for how to avoid this problem? Mea Link to comment Share on other sites More sharing options...
neilestrick Posted March 15, 2013 Report Share Posted March 15, 2013 It shouldn't be the veegum causing the problem. Post the recipe. Link to comment Share on other sites More sharing options...
Matt Oz Posted March 15, 2013 Report Share Posted March 15, 2013 I've been using veegum and haven’t had that problem. I know you have to add the veegum to the water before anything else, so I'm guessing whoever made the glaze may have added it later. Don't know how to fix it, high speed blender? Link to comment Share on other sites More sharing options...
GEP Posted March 15, 2013 Author Report Share Posted March 15, 2013 It shouldn't be the veegum causing the problem. Post the recipe. OK, I don't have the recipe with me, and it might take a few days for me to drive over to get it. But I will post the full recipe in a few days. Mea Link to comment Share on other sites More sharing options...
GEP Posted March 17, 2013 Author Report Share Posted March 17, 2013 Here's the full recipe. All suggestions and ideas welcome! The studio manager who mixes and maintains the classroom glazes says that this glaze has done this for years, so it is not an accidental contamination of the current batch. Warm Jade Green (cone 6 ox, semi-matte opaque light green) 9 ferro frit 3124 40 custer feldspar 16 whiting 9 talc 10 epk 16 silica 5 copper carb 6 rutile 1 veegum t Link to comment Share on other sites More sharing options...
Mark C. Posted March 17, 2013 Report Share Posted March 17, 2013 I have no cures for you Mea but can say that frit is like heavy stones as far as it settles fast especially with that much in the recipe. With all the colorants and frit I would use magma as a suspension agent as it works better. Hopefully others can help with the other issues. Mark Link to comment Share on other sites More sharing options...
bciskepottery Posted March 17, 2013 Report Share Posted March 17, 2013 John Hesselberth's recipe for Xavier's Warm Jade Green is identical except for the inclusion of Veegum; have they always added Veegum to the recipe? Link to comment Share on other sites More sharing options...
GEP Posted March 17, 2013 Author Report Share Posted March 17, 2013 John Hesselberth's recipe for Xavier's Warm Jade Green is identical except for the inclusion of Veegum; have they always added Veegum to the recipe? As far as I know, yes. That probably is the origin of the glaze, and I don't know why veegum was added. I think bentonite is more commonly used in this studio when suspension is needed. Edit: bciske is this a glaze that you have used? If so, does it have a hard-packing issue without the veegum? Or, does it have the sticky sludge problem without the veegum? Mea Link to comment Share on other sites More sharing options...
bciskepottery Posted March 18, 2013 Report Share Posted March 18, 2013 John Hesselberth's recipe for Xavier's Warm Jade Green is identical except for the inclusion of Veegum; have they always added Veegum to the recipe? As far as I know, yes. That probably is the origin of the glaze, and I don't know why veegum was added. I think bentonite is more commonly used in this studio when suspension is needed. Edit: bciske is this a glaze that you have used? If so, does it have a hard-packing issue without the veegum? Or, does it have the sticky sludge problem without the veegum? Mea Thought I had a bucket on the shelf, but I don't. I don't recall a sludge problem, though . . . I made up a small batch to test the glaze maybe two years ago but really don't remember the details. Bruce Link to comment Share on other sites More sharing options...
neilestrick Posted March 19, 2013 Report Share Posted March 19, 2013 Your sludge is probably a mixture of rutile, frit and copper. The veegum probably isn't involved, however if they didn't blunge it before adding it to the recipe it could be. There's enough clay in the recipe that some epsom salts should do a decent job of keeping it suspended. Has this glaze been tested for copper leaching? That's a lotta copper.... Link to comment Share on other sites More sharing options...
GEP Posted March 19, 2013 Author Report Share Posted March 19, 2013 Thanks for all the help everyone! I'll go back to the studio with the following ideas: Was the veegum blunged before it was added? Can the glaze be made without any suspension agents, given that the original recipe did not include any? Could another suspender be substituted? Has the glaze been tested for copper leaching? Well, if we can figure out how to make the glaze better, I'll post results. Thanks again! Mea Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.