shonnie Posted July 14, 2018 Report Share Posted July 14, 2018 I am perplexed why I get this crawling in about 1 in 10 mugs. The mugs are poured in an old hand built mold, from large batches of slip. At leatherhard cleaned up and sanded when dry. I rinse them all well with a clean sponge after bisquing and allow to dry 24 hours before glazing. The glaze is a large batch I’ve been using for a year. I’ve never seen this on anything but these mugs. Link to comment Share on other sites More sharing options...
Min Posted July 15, 2018 Report Share Posted July 15, 2018 @shonnie, can't tell what crawling you are asking about from your image. You don't mean the wide band of raw clay at the bottom of the mugs do you? Link to comment Share on other sites More sharing options...
Chilly Posted July 15, 2018 Report Share Posted July 15, 2018 Can you post a close-up of the problem please? Link to comment Share on other sites More sharing options...
shonnie Posted July 15, 2018 Author Report Share Posted July 15, 2018 I uploaded clearer pictures of the crawling problem. -Shonnie Link to comment Share on other sites More sharing options...
Min Posted July 16, 2018 Report Share Posted July 16, 2018 If you have a glaze with a high amount of uncalcined clay it is going to shrink a lot during drying. Hard to tell by the pictures but are the mugs thin walled? If so when you combine that with a glaze that contains a lot of clay you have a double risk of crawling. (If there are any cracks in the raw glaze before firing then it's pretty certain to crawl when fired.) Are your pots really dry after 24 hours? If they're still damp this is also going to compound the problem of the glaze not bonding with the pot because of being oversaturated. Other things can cause crawling also, dirty bisque from greasy hand lotion or dust or just putting the glaze on too thickly. On 7/14/2018 at 4:11 PM, shonnie said: sanded when dry Can you damp sponge them instead? Not a good idea to do sanding unless you have super good ventilation, or working outside, and wearing a respirator. Link to comment Share on other sites More sharing options...
Gabby Posted July 16, 2018 Report Share Posted July 16, 2018 I think you will get lots of great feedback here if you can upload photos that allow people to see the glazing on the mugs. Link to comment Share on other sites More sharing options...
shonnie Posted July 16, 2018 Author Report Share Posted July 16, 2018 I downloaded the pictures using my iPhone as I don’t have a computer so they might not work for some of you. But I think Min hit the problem. I’ve noticed it’s more likely with the thinner walled pieces. And only with this tenmoku glaze. Thanks Min Link to comment Share on other sites More sharing options...
Min Posted July 16, 2018 Report Share Posted July 16, 2018 Try glazing the inside only of the mug then when the glaze is dry glaze the outside. Link to comment Share on other sites More sharing options...
Rae Reich Posted July 18, 2018 Report Share Posted July 18, 2018 Looks to me (after "zooming in") that you might just have gotten some oil or dust contamination before you glazed, probably from fingers. Try only touching them on the bottom area where there won't be any glaze applied. Link to comment Share on other sites More sharing options...
Babs Posted July 18, 2018 Report Share Posted July 18, 2018 If glazing all mug are you dipping? Like a bit like finger marks as above answer suggests. Glaze thickening after multiple mugs glazed? I.e. specific gravity issue... Link to comment Share on other sites More sharing options...
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