Iona Green Posted June 28, 2021 Report Share Posted June 28, 2021 Hello everyone! I've just finished a firing of vases, all went well but my glazes aren't what I'd hoped for in exterior colour. I've had flowers with water in a few of them recently, and oddly on the base of them after a few hours is a damp ring/the base is damp.I I poured transparent on the inside and the clay is Scarva Earthstone Terracotta Crank E/S65. Do you think the transparent was too thin and is letting water though? My vases are made well, all sealed and simple in shape. So all I can think of is the glaze thickness being an issue? I'm very new to glazing, it's definitely an area that I'm very cautious around but I'm saving up to go on a glaze course soon. Any help would be so appreciated! Thank you all! Link to comment Share on other sites More sharing options...
Babs Posted June 28, 2021 Report Share Posted June 28, 2021 I think your clay hasn't been fired high enough to vitrify. What do the manufacturers recommend for glaze firing. What is its firing range. Is your firing reaching that temp? Link to comment Share on other sites More sharing options...
Fred Sweet Posted June 28, 2021 Report Share Posted June 28, 2021 Babs- Here’ the link from the Scarva site for the clay cited above. https://www.scarva.com/en/Scarva-Earthstone-ES65-Terracotta-Crank-Clay/m-9.aspx Regards, Fred Link to comment Share on other sites More sharing options...
neilestrick Posted June 29, 2021 Report Share Posted June 29, 2021 Anybody know why the Scarva website has never ever worked for me? I just get blank pages whenever I try to look at their clays, the search function never shows anything but tools, and links just go to their main page. Link to comment Share on other sites More sharing options...
Bill Kielb Posted June 29, 2021 Report Share Posted June 29, 2021 31 minutes ago, neilestrick said: I just get blank pages whenever I try to look at their clays, the search function never shows anything but tools, and links just go to their main page. I don’t think it ever worked for me under IOS and when I use Microsoft edge I get a message that it does not ship to the US. Change your country of Origin to Canada for instance and the search function appears to work and display the basic clay properties. The country setting is the flag, four Icons to the left of the right-most top margin icons I believe. Link to comment Share on other sites More sharing options...
Chilly Posted June 29, 2021 Report Share Posted June 29, 2021 Hi @Iona Green As @Babssays, it's probably underfired. UK clay often is quoted with too large a firing range, which is really unhelpful. Clay needs to be fired to almost/at the highest quoted temperatures for it to vitrify. Even with a good coat of glaze on all surfaces, some combinations will leak when fired too low. What temperature/cone did you bisque fore? What temperature /cone did you glaze fire? (I'm assuming you didn't single-fire.) Link to comment Share on other sites More sharing options...
Chilly Posted June 29, 2021 Report Share Posted June 29, 2021 12 hours ago, neilestrick said: never ever worked for me Works for me, suspect it's too clever and knows you're too far away - lol Link to comment Share on other sites More sharing options...
Pres Posted June 29, 2021 Report Share Posted June 29, 2021 @neilestrick, I get their main header with the diamond tools on it, but when I go to the clays only get a side bar with listings but nothing else. best, Pres Link to comment Share on other sites More sharing options...
neilestrick Posted June 29, 2021 Report Share Posted June 29, 2021 12 hours ago, Bill Kielb said: I don’t think it ever worked for me under IOS and when I use Microsoft edge I get a message that it does not ship to the US. Change your country of Origin to Canada for instance and the search function appears to work and display the basic clay properties. The country setting is the flag, four Icons to the left of the right-most top margin icons I believe. @Pres That worked! Thanks, Bill! Weird that some products would show but not others. Link to comment Share on other sites More sharing options...
Iona Green Posted June 29, 2021 Author Report Share Posted June 29, 2021 9 hours ago, Chilly said: Hi @Iona Green As @Babssays, it's probably underfired. UK clay often is quoted with too large a firing range, which is really unhelpful. Clay needs to be fired to almost/at the highest quoted temperatures for it to vitrify. Even with a good coat of glaze on all surfaces, some combinations will leak when fired too low. What temperature/cone did you bisque fore? What temperature /cone did you glaze fire? (I'm assuming you didn't single-fire.) Hey! Thank you everyone for getting back to me! So handy to know at least what might be the issue, such a silly thing to get wrong. I've checked my firings book; Bisque at 950° Glaze Firing at 1220° It's a stoneware clay, so I my peak re-fire temp is 1280°? Do you think I should just pop it back in at that top temp or maybe as it's a re-fire just do it to 1220° again. Thank you so much again! Link to comment Share on other sites More sharing options...
Babs Posted June 29, 2021 Report Share Posted June 29, 2021 Not if your glazes are low fired!! They may run straight off the pots onto the shelved. If for own use you may be able to coat with a product to make them water proof. For future I'd be lookinh for a lower fired clay 1280 pretty high firing if you are firing your own kiln. What temp is it rated for? Don't want to be firing to the max all the time. Shortens the life ofv everthing, almost and shortenss your bankbalance. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted June 30, 2021 Report Share Posted June 30, 2021 Canadian on an iPad here. I have no issues viewing the Scarva site, although the “postage to Canada for this item begins at $21,160.85“ is leaving me with some questions! For those needing clay specs: Terracotta Crank ES65 Firing Temperature 1080°C - 1220°C ES65 Earthstone Terracotta Crank allows you to create large sculptural pieces. It is a beautifully textured, richly coloured, coarse grogged clay. ES65 Terracotta Crank is produced using a blend of Etruria Marls. This body has the excellent working properties of terracotta with the combined strength of a crank. The result is an exceptional body that is ideal for all types of handbuilding processes. Superb terracotta crank body Coarsely grogged Tremendous plasticity Excellent for creating garden pots Can be fired to stoneware Available in 12.5kg bags So. We have a very porous clay body that has a wide firing range, and is recommend for plant pots. I would suggest that even at top firing temperature. this clay body isn’t going to be ideal for work that you need to be waterproof. If your glaze isn’t perfectly fitted, it will likely weep, as you’ve already discovered. If you’re making functional items, it’s a good idea to do a porosity test on your clay body and make sure it’s under 2%, although the closer you can get to 0, the better. Here is a lovely Digitalfire article on some interesting background info, and at the bottom of the page in the links, it’ll take you to a handy tutorial on how to check it for yourself. https://digitalfire.com/glossary/clay+body+porosity Link to comment Share on other sites More sharing options...
Iona Green Posted June 30, 2021 Author Report Share Posted June 30, 2021 15 hours ago, Callie Beller Diesel said: Canadian on an iPad here. I have no issues viewing the Scarva site, although the “postage to Canada for this item begins at $21,160.85“ is leaving me with some questions! For those needing clay specs: Terracotta Crank ES65 Firing Temperature 1080°C - 1220°C ES65 Earthstone Terracotta Crank allows you to create large sculptural pieces. It is a beautifully textured, richly coloured, coarse grogged clay. ES65 Terracotta Crank is produced using a blend of Etruria Marls. This body has the excellent working properties of terracotta with the combined strength of a crank. The result is an exceptional body that is ideal for all types of handbuilding processes. Superb terracotta crank body Coarsely grogged Tremendous plasticity Excellent for creating garden pots Can be fired to stoneware Available in 12.5kg bags So. We have a very porous clay body that has a wide firing range, and is recommend for plant pots. I would suggest that even at top firing temperature. this clay body isn’t going to be ideal for work that you need to be waterproof. If your glaze isn’t perfectly fitted, it will likely weep, as you’ve already discovered. If you’re making functional items, it’s a good idea to do a porosity test on your clay body and make sure it’s under 2%, although the closer you can get to 0, the better. Here is a lovely Digitalfire article on some interesting background info, and at the bottom of the page in the links, it’ll take you to a handy tutorial on how to check it for yourself. https://digitalfire.com/glossary/clay+body+porosity Ah thank you, I'm so new to it all and it's such a learning curve! I'll have a gander at the article now Link to comment Share on other sites More sharing options...
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