April Crowell Posted May 24, 2019 Report Share Posted May 24, 2019 I'm looking for help with a recent glaze issue. I've been using the same clay and white glaze for a couple of years. Now, all of a sudden, I'm getting tiny black specks in the glaze, and it's ruining the clean look I'm trying to achieve. I've used different batches of my perfered clay and glaze, installed new elements, throughly vacuumed the kiln, kept my bisqueware clean. I don't know what else to do to, and don't know what's causing the black specks. Does anyone have any insight on this issue? Link to comment Share on other sites More sharing options...
Min Posted May 24, 2019 Report Share Posted May 24, 2019 Hi April and welcome to the forum. Are you using commercial glaze or mixing up your own? Also, is it happening on all the pots or ones from a certain location in the kiln? What shape is the kiln jacket in, specifically the band around the lid (if it's an electric top loader). Are the specks visible on bisque? Post a closeup picture of the black specks and it might give us a clue as to what the cause is. Link to comment Share on other sites More sharing options...
Mark C. Posted May 24, 2019 Report Share Posted May 24, 2019 Welcome to the forum sieve the glaze thru an 80 mesh vacuum the kiln roof and loading edge-sweep the shelves-top and bottoms photos would help Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted May 24, 2019 Report Share Posted May 24, 2019 +1 for photo requests. Also, which clay body are you using, and glaze recipe, if you can. Did the problem start with a new batch of clay or any glaze ingredients? Link to comment Share on other sites More sharing options...
April Crowell Posted May 24, 2019 Author Report Share Posted May 24, 2019 Thanks for replying! I'm using a commercial glaze. I called the company but they haven't had any other complaints about the two glaze batch numbers I've used most recently. I'm not seeing any visible flaws on the bisqueware. I'm vacuuming the lid, shelves and posts too; it's happening on every piece, no matter where it's been in the kiln; the kiln jacket seems to be in great shape, still fitting snug. Sieving is the only thing I haven't tried yet, so I'll definitely do that. Here's a photo... as you can see, my pottery is starting to look like cookies and cream ice cream, coincidentally, it's my favorite. Link to comment Share on other sites More sharing options...
April Crowell Posted May 24, 2019 Author Report Share Posted May 24, 2019 The clay is Laguna B-Mix and the glaze is Laguna Colonial White. Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted May 24, 2019 Report Share Posted May 24, 2019 are the lids on the glaze containers metal; are you using any metallic containers, tools, brushes, etc. in the glazing steps? Link to comment Share on other sites More sharing options...
April Crowell Posted May 24, 2019 Author Report Share Posted May 24, 2019 I wondered if it was rust too. But all the glaze jars are plastic and my brushes don't appear to be rusted on the bands. As mentioned in another comment, I think I need to try sieving the glaze. Surely that will help. Thank you, everyone, for taking the time to reply. I really appreciate it! Link to comment Share on other sites More sharing options...
Min Posted May 24, 2019 Report Share Posted May 24, 2019 If putting the glaze through an 80 mesh sieve doesn't solve the problem I would contact Laguna. Let them know everything you've done to solve the issue, glaze and clay batch numbers and your results. Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted May 24, 2019 Report Share Posted May 24, 2019 are you adding any water to the glaze? Check to see if the iron (or other trace elements) content has increased since you last had pure white glaze. Our water system is having its routine "flushing" for cleaning the distribution piping from corrosion sediments. LT Link to comment Share on other sites More sharing options...
Mark C. Posted May 24, 2019 Report Share Posted May 24, 2019 Rust particles (iron) can be all over many surfaces. Check your clay cutting wires-jar lids -vacumme the kiln again as well as the bands around the lid and the lid. It would also help by doing your elemnts with a soft brush on the vacume as well. Seive the glaze-Just think like a small ruct particle . I would also test a pice of clay unglazed to see if the specks are in that body as well in a fire. Since you are using a commercial glaze you have ZERO control other than sieving it. The finer the screen the better for those paricles look really small. looks like rust to me. Link to comment Share on other sites More sharing options...
neilestrick Posted May 25, 2019 Report Share Posted May 25, 2019 Do you see the specks on the unglazed foot ring, or just the glazed part? Link to comment Share on other sites More sharing options...
April Crowell Posted May 25, 2019 Author Report Share Posted May 25, 2019 Thanks for all the tips! Based on all the info gathered, my next step is to sieve the glaze. Will check back with results! Link to comment Share on other sites More sharing options...
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