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Kristin_Gail

Super-Old Glaze: Hardpanned?

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I have many, many buckets of glaze in the basement that have sat, untouched, for seven or more years. They each (at least the ones I've checked) still have their water, but the rest of the glaze is an absolute rock in the bottom.

 

When I search online for solutions, I get results for glazes that hardpan within a few days. Looks like the way to deal with this issue is 2 Tbsp of water saturated with epsom salts. Do I apply the same trick to these glazes? Or is there a better way to tackle these monsters?

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I have many, many buckets of glaze in the basement that have sat, untouched, for seven or more years. They each (at least the ones I've checked) still have their water, but the rest of the glaze is an absolute rock in the bottom.

 

When I search online for solutions, I get results for glazes that hardpan within a few days. Looks like the way to deal with this issue is 2 Tbsp of water saturated with epsom salts. Do I apply the same trick to these glazes? Or is there a better way to tackle these monsters?

 

 

you'll need to get stuff off the bottom first. reach in and stir with hand, (some may will protest) , get a wooden spoon and use burr mixer or hand held mixer. john britt uses one so do I.

 

after that then consider other, epsom or whatever isin't going to magically soften 7 year sediment.

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I have many, many buckets of glaze in the basement that have sat, untouched, for seven or more years. They each (at least the ones I've checked) still have their water, but the rest of the glaze is an absolute rock in the bottom.

 

When I search online for solutions, I get results for glazes that hardpan within a few days. Looks like the way to deal with this issue is 2 Tbsp of water saturated with epsom salts. Do I apply the same trick to these glazes? Or is there a better way to tackle these monsters?

 

 

you'll need to get stuff off the bottom first. reach in and stir with hand, (some may will protest) , get a wooden spoon and use burr mixer or hand held mixer. john britt uses one so do I.

 

after that then consider other, epsom or whatever isin't going to magically soften 7 year sediment.

 

 

I saw a video, where the person used a large loop tool, to scrape through the settled glaze. This seems like a great idea, for those really heavily settled glazes.

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Here is what you do;

1.Pour off the surface water into a clean container. You will be returning it to the glaze later.

2. Get you pear corer [large trimming tool] Loosen up all the glaze.

3.You may even have to pour it out onto a canvas.

4. Pour the water back in.

5.Gradually add the glaze, using a drill with a paint stirrer.

6.Once you have all the glaze back in, add enough water to make the glaze the consistency of cream.

7.Sieve through an 80 mesh sieve into a clean pail.

8.Wash original pail. Then sieve glaze back through a 100 mesh sieve.

9. You do not need Epsom salts. The reason glazes go rock hard immediately, is because they do not have enough clay in them. Friitted glazes are the worst for this. I always add 3% Bentonite to my glazes. Also makes the unfired surface of the glaze tough.

Enjoy!

TJR.

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If the hardpan is too hard to chip into pieces, you can decant off and save the water. Dry the hardpan, then ball mix the content until powdered. Reconstitute with the saved water, add 2- 3% bentonite, then sieve.

 

Jed

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Here is what you do;

1.Pour off the surface water into a clean container. You will be returning it to the glaze later.

2. Get you pear corer [large trimming tool] Loosen up all the glaze.

3.You may even have to pour it out onto a canvas.

4. Pour the water back in.

5.Gradually add the glaze, using a drill with a paint stirrer.

6.Once you have all the glaze back in, add enough water to make the glaze the consistency of cream.

7.Sieve through an 80 mesh sieve into a clean pail.

8.Wash original pail. Then sieve glaze back through a 100 mesh sieve.

9. You do not need Epsom salts. The reason glazes go rock hard immediately, is because they do not have enough clay in them. Friitted glazes are the worst for this. I always add 3% Bentonite to my glazes. Also makes the unfired surface of the glaze tough.

Enjoy!

TJR.

 

 

This is about how I do it and works great-The drill is the key-you can also beat up the chunks if they are dry with a hammer then add water.

Mark

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i would try it the way mentioned above, but i would also try removing all the surface water, let sit for a couple days open to hopefully pull away from the side of the bucket slightly, place inside garbage bags and break up with hammer - then try to reconstitute with either a paint mixer or even a stick blender if it's smaller volume, then sieve.

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Thank you so very much, everyone. I'll tackle it today. I only need one glaze (of about 30) right now, thankfully.

 

It's incredible how much has survived this hiatus - both in the physical world, and in my muscle memory. There's an awful lot that *didn't* survive in my brain, however. Taking a while to brush-up. Thank you again!

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looking for something else and came across this.  i was given a pile of old glazes in plastic buckets.  i worried all 26 miles home that the brittle old buckets would break and leak all over the car interior.  

 

my suggestion is that as you reconstitute these older glazes, replace the buckets.  supermarkets that have bakery sections sometimes give them away.  donut shops also.  just ask,  some don't.

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I have a blue green celadon that I mixed a large batch (20,000 plus grams) and it worked beautifully.  It sat for a month and settled to a hard brick on the bottom as others have described here.  After reading a bunch of info on this issue I added about 1.5% (it already had 1%) Bentonite to the glaze and re-strained it.  The glaze no longer settles but it seriously changed the color of the glaze – from a beautiful blue green to a weak light green.  Here is the recipe:

 

F4 Spar                 36.5%

Silica                      32.3

Whiting                 14.6

Zinc OX                 11.5

EPK                          5.2

Bentonite              2.5  (total with additions)

RIO                             1

 

Hard to believe that the small amount of iron in Bentonite would change the glaze this dramatically.  Any ideas on how to systematically bring it back would be most appreciated.

 

Thanks

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I have a blue green celadon that I mixed a large batch (20,000 plus grams) and it worked beautifully.  It sat for a month and settled to a hard brick on the bottom as others have described here.  After reading a bunch of info on this issue I added about 1.5% (it already had 1%) Bentonite to the glaze and re-strained it.  The glaze no longer settles but it seriously changed the color of the glaze – from a beautiful blue green to a weak light green.  Here is the recipe:

 

F4 Spar                 36.5%

Silica                      32.3

Whiting                 14.6

Zinc OX                 11.5

EPK                          5.2

Bentonite              2.5  (total with additions)

RIO                             1

 

Hard to believe that the small amount of iron in Bentonite would change the glaze this dramatically.  Any ideas on how to systematically bring it back would be most appreciated.

 

Thanks

 

I agree that it is hard to believe the Bentonite changed the glaze that much. Maybe drop the Bentonite and add Epsom Salt. I think it has enough EPK in it to work with Epsom Salt. Maybe start with .5% and go up from there.

 

Jim

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The issue is I have 20,000 grams of the now insipid green glaze that I need to bring back to the beautiful blue green.  Since the only oxide in this is RIO, I really wonder if it is the small amt of iron in the Bentonite that caused this (we are talking 600 grams or so out of 20,000 plus).  I want to try and bring the liquid glaze back and want to know if anyone has a good process for doing tihs?

 

Many thanks

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if it is a cone 6 glaze, hesselberth and roy put out the book "mastering cone six glazes".   when i messed up one mr hesselberth was kind enough to fix it for me with a simple addition.   try emailing him the recipe and see what he says.

 

if it is a cone 10 glaze, try doing the same with tom coleman.  he is a sweetheart and will help, too.

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Quick update.  I did contact Tom Coleman and he responded very quickly.  He said he thought that the Bentonite did indeed effect the glaze and said I should add 25 grams of Mason Stain #6600 to bring it back to blue green.

 

He also said he no longer uses Bentonite or Epsom salts to keep a glaze in suspension.  He uses a small amount of muriatic acid like one tablespoon for 20,000 grams.  Says it works great. 

 

I will try both of these over the next month or so and post and update.

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looking for something else and came across this.  i was given a pile of old glazes in plastic buckets.  i worried all 26 miles home that the brittle old buckets would break and leak all over the car interior.  

 

my suggestion is that as you reconstitute these older glazes, replace the buckets.  supermarkets that have bakery sections sometimes give them away.  donut shops also.  just ask,  some don't.

oldlady;

Man,you buy a glaze bucket for 50 cents at a bakery and you expect it to last! My buckets are all falling apart as well.You think they would last 20 or thirty years with old glaze in them, but,no, not the case.I have buckets splitting all the time!

TJR.

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Red Rocks;

I am looking at your glaze recipe,and it does not look correct to me. If it is a cone 10 stoneware celadon, it does not look like it has enough iron to make a celadon. I usually have at least 2% red iron oxide in a celadon.

If you say that bentonite is providing iron to the recipe, you would have more of a green, not less.

Also, what it causing the blue to happen? I do not see any cobalt or copper in your recipe.

TJR.

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Couldn't agree more about the low iron and lack of colbalt.  However as I am learning to work with a new kiln, I first mixed a 5000 gram batch and it came out a wonderful blue green, then a 10,000 gram batch, again the beautiful blue green I expected.  So not sure what causes the blue, just know that it is.  It was when I went to the very large bucket and 20,000 grams plus that it did the hard pan number.  I actually glazed a few pieces that came out blue green from the large batch, then I made the mistake of putting the additonal bentonite and the Epsom salts in the already mixed batch and that is when it turned light green.

 

I think Tom Coleman's idea makes sense as Mason Stain #6600 is a strong black stain and a little should go a long ways.  I will experiment with it before trying to change the 20,000 gram bucket.

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Old Lady:

 

A good question but it was not a new batch of chemicals.  I actually glazed 4 or 5 pieces with the new 20,000 gram bucket and they came out perfect.  I went back to glazing several days later and the glaze was hard-panned.  That is when I added the bentonite and epsom salts.

 

Next firing in a month or so, I will pour out half of the bucket into a a separate bucket and add the Mason Stain #6600 and see how it turns out. 

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I used to have problems with hardpanned glazes in the HS.  Took the lid off, let them dry out if not much water or pour off water. turned bucket upside down on an open pillow case. Dumped out glaze into case, broke up as much as possible with open claw hammer without hitting pillow case, closed up pillow case and ran through slab roller with high setting, then lower.  Turned pillow case inside out in clean bucket, added water, mixed, strained twice, then added 2 tablespoons of saturated epsom salt solution.  This worked for me time and again, as working in a classroom there is not a whole lot of time to dig things out of a bucket bits at a time, never hurt the slab roller, and pillow case worked great-always wear a mask and gloves when using hammer claw. <_<

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