alli Posted October 29, 2021 Report Share Posted October 29, 2021 Hello! Does anyone have advice on how to "fix" a commercial glaze? I mostly use Laguna #65 and make dishware, so crazing drives me crazy haha. I've never made my own glazes, and I rely on the commercial stuff. I always use cone 6 clay and glazes, but every clear glaze I've tried doesn't fit. I've used colored glazes with no problem, but even if I buy the clear glaze of the same brand, it crazes. It doesn't matter if I fire hotter or cooler, apply it thicker or thinner, nothing works. I've been trying to find a clear glaze for over a year, and at this point, I have 4 or 5 brands of clear glaze mixed up. I feel like it would be a waste to scrap it all. If anyone could help me salvage what I have, it would be much appreciated! Other glaze brand recommendations are welcome, or clay recommendations if the clay body is the problem Link to comment Share on other sites More sharing options...
Min Posted October 29, 2021 Report Share Posted October 29, 2021 How far apart are the craze lines? It's tricky to alter a glaze recipe when we don't have the recipe but adding silica and clay (epk) sometimes is enough to reduce crazing if it isn't too severe. The closer the craze lines are the less chance this simple fix will work. Link to comment Share on other sites More sharing options...
Hulk Posted October 30, 2021 Report Share Posted October 30, 2021 Hi Alli! Very likely a clear glaze can be formulated that will fit the clay, however, might be a difficult "find," for crazing involves both the glaze and the clay (that don't fit each other). I went with lower and lower expansion clear glazes, with improvement, but no "win" - then tried a different clay, aha!, which my lowest expansion clear fits very well. Since, have found another mid range white stoneware that my low e clear fits, and, And, the source is on a regularly travelled route (it's three hundred miles away, but it's On the Way! to somwhar we go). On the other end, a clay that I liked, which I had a good clear for, changed dramatically (confirmed by test and re-test; the clay changed), crazely city. Your clay supplier might be able to help - these glazes craze on that clay; can you recommend a clay to try that these glazes may fit better? ^ if/when you find someone who can answer, count your blessings! Link to comment Share on other sites More sharing options...
alli Posted October 30, 2021 Author Report Share Posted October 30, 2021 18 hours ago, Min said: How far apart are the craze lines? It's tricky to alter a glaze recipe when we don't have the recipe but adding silica and clay (epk) sometimes is enough to reduce crazing if it isn't too severe. The closer the craze lines are the less chance this simple fix will work. It’s pretty bad…I’m thinking I need to look for a different clay body. I found a sample cup where I used the same clear glaze on a laguna speckled clay; no crazing at all. If you have any recommendations for another white stoneware clay, let me know! Link to comment Share on other sites More sharing options...
alli Posted October 30, 2021 Author Report Share Posted October 30, 2021 1 hour ago, Hulk said: Hi Alli! Very likely a clear glaze can be formulated that will fit the clay, however, might be a difficult "find," for crazing involves both the glaze and the clay (that don't fit each other). I went with lower and lower expansion clear glazes, with improvement, but no "win" - then tried a different clay, aha!, which my lowest expansion clear fits very well. Since, have found another mid range white stoneware that my low e clear fits, and, And, the source is on a regularly travelled route (it's three hundred miles away, but it's On the Way! to somwhar we go). On the other end, a clay that I liked, which I had a good clear for, changed dramatically (confirmed by test and re-test; the clay changed), crazely city. Your clay supplier might be able to help - these glazes craze on that clay; can you recommend a clay to try that these glazes may fit better? ^ if/when you find someone who can answer, count your blessings! Yes! I think you’re right! I was looking through my test mugs today and found that the clear glaze crazed on all the white clay pieces but not on this other speckled clay. I’ll definitely have to ask my supplier for suggestions. Thanks! Link to comment Share on other sites More sharing options...
Min Posted October 30, 2021 Report Share Posted October 30, 2021 1 hour ago, alli said: It’s pretty bad…I’m thinking I need to look for a different clay body. I found a sample cup where I used the same clear glaze on a laguna speckled clay; no crazing at all. If you have any recommendations for another white stoneware clay, let me know! Have you tried Laguna MS29 clear glaze? It's expensive but good on low expansion claybodies. Underfiring can cause crazing, are you verifying you are getting to a full cone 6 with witness cones? Sorry but I'm not much help with recommending a claybody from your part of the world, I don't have access to many that you probably could get. Link to comment Share on other sites More sharing options...
alli Posted October 30, 2021 Author Report Share Posted October 30, 2021 5 hours ago, Min said: Have you tried Laguna MS29 clear glaze? It's expensive but good on low expansion claybodies. Underfiring can cause crazing, are you verifying you are getting to a full cone 6 with witness cones? Sorry but I'm not much help with recommending a claybody from your part of the world, I don't have access to many that you probably could get. This was actually fired a cone higher because I tried to force the fit :/ I was able to delay the crazing for a few days, but in the end, it's inevitable. I'll look into the laguna clear, thanks! Link to comment Share on other sites More sharing options...
Bill Kielb Posted October 31, 2021 Report Share Posted October 31, 2021 3 hours ago, alli said: This was actually fired a cone higher because I tried to force the fit :/ I was able to delay the crazing for a few days, but in the end, it's inevitable. I'll look into the laguna clear, thanks! Hard to force a fit by firing actually in my experience. Actually can never remember being successful trying to do that. Finding or adjusting a fit (for known recipes) seems to be more successful for me. Link to comment Share on other sites More sharing options...
AmyBurn Posted November 15, 2021 Report Share Posted November 15, 2021 I have been using Laguna B-Mix (without grog) for years with Amaco Sahara Highfire (HF-9) zinc free clear to make craze free mugs and bowls. I decorate them with SMUG's (semi-moist underglazes) while greenware, then bisque fire them to cone 05. I then apply the clear glaze and glaze fire to Cone 5. I hope that helps! Link to comment Share on other sites More sharing options...
Bill Kielb Posted November 15, 2021 Report Share Posted November 15, 2021 @AmyBurn Do you have any leftover from previous batch to test against? Same with the clay btw. Amaco has been fine for me however at one point my bottle of zinc free wasn’t and washed out about a weeks worth of very intricate decorative art. After that we started making our own. Mistakes can happen on all sides though. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted November 19, 2021 Report Share Posted November 19, 2021 Shifts can also occur in the clay batch. Link to comment Share on other sites More sharing options...
shawnhar Posted November 19, 2021 Report Share Posted November 19, 2021 On 10/30/2021 at 12:47 PM, alli said: It’s pretty bad…I’m thinking I need to look for a different clay body. I found a sample cup where I used the same clear glaze on a laguna speckled clay; no crazing at all. If you have any recommendations for another white stoneware clay, let me know! I had to give up on my cone 6 porcelain because it did exactly the same thing with my clear glaze, just doesn't fit that clay. I am using Highwater "Little Loafer's" with no issues and know "Bella's Blend" from them has no crazing with the same clear glaze. Both are white stoneware and very smooth clays. Link to comment Share on other sites More sharing options...
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