Tsculpt Posted October 16, 2020 Report Share Posted October 16, 2020 Hi, I've been using mainly 06 mayco glazes and noticed the rim's on mugs chipping rather easily. I apply 3 coats of glaze to 04 bisque and not sure why I'm having this issue. Chipped off pieces are often very small. I dont think it's from the surface being too smooth for glaze to attach... Please let me know what possible issues thanks so much ! Link to comment Share on other sites More sharing options...
Bill Kielb Posted October 16, 2020 Report Share Posted October 16, 2020 Pictures for sure on this one. Is this before firing, after firing? If after did the base claybody chip with the glaze or just the glaze? Is this commercial glaze or a mixed from a recipe? Does it look like it fired to maturity? Lots of questions, I think we really need pictures to render a decent opinion. Link to comment Share on other sites More sharing options...
neilestrick Posted October 16, 2020 Report Share Posted October 16, 2020 Chipped when bumped, or flaking off on its own? Link to comment Share on other sites More sharing options...
Tsculpt Posted October 17, 2020 Author Report Share Posted October 17, 2020 Chipped when bummed, but not all that hard. All chips are usually small and happen just when handling them. Link to comment Share on other sites More sharing options...
Bill Kielb Posted October 17, 2020 Report Share Posted October 17, 2020 Sounds like chipping at the raw glaze stage, before firing. If yes, carefull handling is in order IMO. Anywhere the glaze is thick With a limited area of attachment is susceptible. Some glazes more than others. Link to comment Share on other sites More sharing options...
Sorcery Posted October 17, 2020 Report Share Posted October 17, 2020 I'm guessing the rim is too thin, and post fire. Sorce Link to comment Share on other sites More sharing options...
Babs Posted October 17, 2020 Report Share Posted October 17, 2020 Poster says glazed on 04 bisqueware to C 06 @Tsculpt Need photos . Glaze only or clay chipping too. Dont be afraid of folk cvopying, we aste too busy. Wondering here if clay is a high firing body and so fragile. Link to comment Share on other sites More sharing options...
Min Posted October 17, 2020 Report Share Posted October 17, 2020 @Tsculpt, the reason we are all asking for photos of the chipping is because it could well be shivering thats happening. Shivering is when there isn't a good fit between the clay and the glaze and sharp little shards of glaze either spontaneously break off (usually on rims or edges) or it can happen when rims or edges are tapped. Shivering is obviously dangerous, especially with functional ware, can't tell without a photo if it might be that or simply chipping from a weak underfired body or glaze. Link to comment Share on other sites More sharing options...
Tsculpt Posted October 17, 2020 Author Report Share Posted October 17, 2020 Chipping after firing. Sometimes right after when bummed with another ceramic peice. Mayco brand glaze Link to comment Share on other sites More sharing options...
Min Posted October 18, 2020 Report Share Posted October 18, 2020 Thanks for posting the picture, yes, that is shivering. Unfortunately there is nothing you can do to save these mugs, they would be dangerous to use and should be smashed prior to disposing of them. Shivering is the opposite of crazing, the glaze is under too much compression and flakes/chips away from the body. Since you are using a commercial glaze we can't offer a fix for the glaze recipe but you are going to need to try a different glaze or a different claybody. Clay and glaze need to "fit" each other. I'ld suggest just buying a small amount of a different line of glaze and make up some quick simple cylinders (they can just be thin and rough, don't need a base). Glaze them thickly in whatever glaze you want to test then fire as usual. Tap them with the something dense like a screwdriver handle and see what happens. Hopefully your next glaze won't have this fit issue. If you are in love with this glaze then try another clay body. Link to comment Share on other sites More sharing options...
Sorcery Posted October 18, 2020 Report Share Posted October 18, 2020 Yeah those are nice. Smash em well and don't give up! What's your clay? Sorce Link to comment Share on other sites More sharing options...
Tsculpt Posted October 18, 2020 Author Report Share Posted October 18, 2020 I use a white clay that specifically noted works well with commercial glazes. Is there clay suggest to work with these commercial mayco glazes I have invested so much into these glazes it would be better to switch clay at this point. Link to comment Share on other sites More sharing options...
Min Posted October 18, 2020 Report Share Posted October 18, 2020 Get the batch number code from the box and talk to your supplier and/or Standard. Tell them about the shivering and ask if it is a bad clay batch issue. Ask if they have had similar reports from other potters. Link to comment Share on other sites More sharing options...
Sorcery Posted October 18, 2020 Report Share Posted October 18, 2020 13 hours ago, Tsculpt said: invested so much into these glazes it would be better to switch clay at this point. If that's the most economical. It very well could be a faulty batch or box of clay. Or perhaps just one of the glazes. The bad thing is the rest of that batch may be sitting unused in a school somewhere right now, so there may be no word of it being bad. Truth truth, with all "yes it is shivering" in mind for safety, I'm still not convinced. Since according to the text, it could still be them chipping when bumped. No sense chasing gremlins. Sorce Link to comment Share on other sites More sharing options...
neilestrick Posted October 18, 2020 Report Share Posted October 18, 2020 Looks like shivering to me. The shape of the chip on the left end is exactly how I would expect shivering to look. Plus shivering is most commonly seen on the lip, and most commonly seen with low fire white bodies. Link to comment Share on other sites More sharing options...
Bill Kielb Posted October 18, 2020 Report Share Posted October 18, 2020 Interesting in that it looks like underglaze was used to more solidly accent the rim area as well. Most commercial glaze folks will say they only test with all their product for compatibility. Is that Mayco underglaze? Seems the chipped areas have lost their underglaze as well. Link to comment Share on other sites More sharing options...
Mark C. Posted October 19, 2020 Report Share Posted October 19, 2020 It can be many things but a change of clay or underglaze is easiest. Testing needs to happen after that-All the pots you made need to be destroyed as they are unsafe. Real bummer part of the journey-happens to us all sooner or later. Link to comment Share on other sites More sharing options...
Tsculpt Posted October 19, 2020 Author Report Share Posted October 19, 2020 where i order clay from suggested to gloss fire to cone 05 instead of 06 but would this really solve the issue? also wondering if it could be an application error on my part. however looking into switching clay all together to find one that fits these glazes best thanks! Link to comment Share on other sites More sharing options...
Pres Posted October 19, 2020 Report Share Posted October 19, 2020 I am wondering, if you compressed the rims when throwing them, did you use a chamois or other method to compress the rim. If you used a sponge, the clay particles and grog get exposed and do not have as much body adhesion on the rim. Just a thought, best, Pres Link to comment Share on other sites More sharing options...
Bill Kielb Posted October 20, 2020 Report Share Posted October 20, 2020 6 hours ago, Tsculpt said: f it could be an application error on my part. I would suggest to see it tested without the underglaze actually to rule that in or out. Link to comment Share on other sites More sharing options...
Tsculpt Posted October 20, 2020 Author Report Share Posted October 20, 2020 thanks all but i do not use underglazes. Ive been using mayco foundation glazes and it is always the black that chips. i have had more then 1 container of black and also had 2 different lots of white clay. I talked to my ceramic supplier they told me to gloss fire at 05 instead of 06. I then talked to Mayco directly they told me never to do 05 instead of 06 for the gloss fire. Then also stated that standard 105 clay is a recommended clay for their brand. Im pretty overwhelmed. Sorta just getting the run around. Really wondering if i just need to do a overall thicker application to solve the issue. but honestly at this moment I think im just going to look into high fire clay for dinnerware because i dont want to put anyone at risk if this is going to keep happening. Link to comment Share on other sites More sharing options...
Min Posted October 20, 2020 Report Share Posted October 20, 2020 30 minutes ago, Tsculpt said: i have had more then 1 container of black and also had 2 different lots of white clay. What did Standard say when you let them know about the shivering? Did you give them the lot numbers? Could be that you got some that wasn't mixed properly. 30 minutes ago, Tsculpt said: Really wondering if i just need to do a overall thicker application to solve the issue. but honestly at this moment I think im just going to look into high fire clay for dinnerware because i dont want to put anyone at risk if this is going to keep happening. Thicker will just make the shivering worse. Shivering can happen with any claybody but is most common with white lowfire bodies and isn't very common with mid and high fire. Advantage of going to a midrange claybody for functional ware is if you choose a clay that has less than 2% absorption then you won't have issues with pots getting hot in the microwave, crazing and weeping from moisture seeping into the clay and they tend to chip less than lowfire. 30 minutes ago, Tsculpt said: I then talked to Mayco directly they told me never to do 05 instead of 06 for the gloss fire. I think this is a bit of a red herring, many kilns don't fire evenly, especially older large manual ones. It would be easy to get to 05 in the middle of the kiln and 06 in the cooler parts near the floor or lid. Link to comment Share on other sites More sharing options...
Babs Posted October 20, 2020 Report Share Posted October 20, 2020 Thicker won't do it.. Test tiles only way to go Link to comment Share on other sites More sharing options...
Tsculpt Posted October 20, 2020 Author Report Share Posted October 20, 2020 1 minute ago, Babs said: Thicker won't do it.. Test tiles only way to go so i have many test tiles, never had an issue with chipping/shivering. it seems only specific pieces are effected by this. i went back to check a number of lips on mugs and bowls and its either they are completely fine or will chip off when tapped against another. Link to comment Share on other sites More sharing options...
Babs Posted October 21, 2020 Report Share Posted October 21, 2020 Maybe really compress lips as Pres suggested. Looks like you have two sharp ridges to your rims...are the rims chipping on the pots with this design of rim? If so maybe focus n compressing to a rounded top to rim. Worth a try. Link to comment Share on other sites More sharing options...
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