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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!

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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.

Edited by Bill Kielb
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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.)

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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.

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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!

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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.

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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

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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 :)

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