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Katie Piro

How many glazes in a home studio...?

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1 hour ago, Sorcery said:

Thanks @Bill Kielb I thought maybe Gillespie was mined in the East hence why we have it here. I read it is a pound for pound replacement, but note the chemistry quite different.

Are you ordering Gerstley from Laguna direct? 

Forgive my pestery uneccesary questions!

 

Sorce

Yes,

Gillespie for me is significantly different than Gerstley.  We get it from Laguna. I tend to design glazes with known durable flux ratios and then test, so controlling flux proportion and apportionment is important to me. In addition to the normal testing, gloss meter and lots of dishwasher cycles is an ok way to give me some confidence for something I believe will be long term.

Natural materials change so as @Pres said I realize Some just become obsolete and always have an eye for what may become a new best recipe. To get to that point it takes a bunch of testing including practical firing ranges, claybodies etc... so I don’t jump from one goto recipe to the next a bunch though.

Gloss and matte clear base, decent liner white and a few goto colors is it really right now which includes some reduction and cone ten stuff as well.

Edited by Bill Kielb

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5 hours ago, Sorcery said:

I read it is a pound for pound replacement, but note the chemistry quite different.

Gillespie borate is fairly close to Gerstley borate, side by side chart with the data coming from Insight below. Wouldn't take much tinkering to get a recipe with exact same formula. Analysis is using current figures for Gerstley but it's likely that other software could have slightly different figures depending on the materials data.

368248922_ScreenShot2020-05-08at3_00_29PM.png.88220e5557ce5be94988d5d8d0cc1c85.png

5 hours ago, Sorcery said:

I thought maybe Gillespie was mined in the East

Gillespie Borate is a blended material from Hammill & Gillespie in New Jersey.  Laguna bought up the remaining supply of Gerstley Borate from the mine in California, before then there was a period of time when it was thought it wouldn't be available at all. Ceramic supply companies scrambled to come up with a replacement, there were a few substitutes made by various companies, Laguna Borate, Boraq etc, Gillespie Borate being one of them.

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9 hours ago, Pres said:

Gerstley over the years tended to be inconsistent. It was one of the reason I move more towards fris in the 90's

Gerstley memo from 2011 released by Laguna as to Gerstley composition and availability..

Chemical_Composition_of_Gerstley_Borate.pdf

Edited by Bill Kielb

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You all are so helpful!

Thanks!

For me, testing and discovering is winning over doing chemistry.

OP..if you haven't ....oh wait wait... btw...of your last name is actually Piro, that is awesome. Good Potter name! Anyway...

Watch the YouTube series by the Goldmark Gallery. I am amazed at how so many excellent artists have completely different processes and forms, colors.

I find it to be an excellent... insight..lol...to what "finding your voice", or your "body of work", or color palette can be. A lesson in it if that makes sense.

Sorce

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3 hours ago, Sorcery said:

You all are so helpful!

Thanks!

For me, testing and discovering is winning over doing chemistry.

OP..if you haven't ....oh wait wait... btw...of your last name is actually Piro, that is awesome. Good Potter name! Anyway...

Watch the YouTube series by the Goldmark Gallery. I am amazed at how so many excellent artists have completely different processes and forms, colors.

I find it to be an excellent... insight..lol...to what "finding your voice", or your "body of work", or color palette can be. A lesson in it if that makes sense.

Sorce

Thanks @Sorcery!! Piro will be my married name (currently engaged). Flows a lot better than McKeown and I probably won't have to tell people how to spell it as frequently. I'll check out that YouTube series. Thanks guys!

Katie

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Congratulations! My Fishing buddy married a Katie and they have a second on the way! I wish you the best!

I had an Irish cat that used to meow like that! 

Glaze on!

 

Sorce

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Now I get that this forum is largely electric fire and the ones that gas fire mostly do kitchenware.  But really, no one mentions shinos?

I get more different results from one bucket of basic shino with different applications than all the rest of my buckets.

By far my favorite glaze.  I have to consciously select other glazes. 

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2 hours ago, CactusPots said:

Now I get that this forum is largely electric fire and the ones that gas fire mostly do kitchenware.  But really, no one mentions shinos?

I get more different results from one bucket of basic shino with different applications than all the rest of my buckets.

By far my favorite glaze.  I have to consciously select other glazes. 

Shinos are great but I am a believer in using a liner for functional ware if using Shino so a little less functional but cool. Especially the random surprise that got slightly caught in the rain on your way into the studio. Lots of  cool cone 6 Shino being done at Mudfire pottery.

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On 5/8/2020 at 5:27 PM, Pres said:

Gerstley over the years tended to be inconsistent. It was one of the reason I move more towards fris in the 90's

When I was the tech at A.R.T. Clay back in the early 2000's, a rep from one of the big clay suppliers (HC Spinks, I think) stopped in the store to visit, since we bought truckloads of raw materials from them. He was on his way up to Sheboygan, as they supplied tankers of casting slip to Kohler. Anyway, we were talking and somehow the subject of Gertsley Borate came up because this was during the time that it became unavailable for a while, before Laguna started making it again. He was shocked when he heard that potter use it. If I remember correctly he referred to it as 'junk' or possibly something less kind. He said it was so inconsistent that almost nobody in industry would touch it. It was primarily used by the roofing tile industry, but certainly nobody used it in glazes or anything that required precision or consistency. That's when I decided that I would not use it any more.

Gillespie, when substituted directly for Gerstley, tends to be a little bit stronger, and make glazes runnier. I typically start with about 3% less when using Gillespie.

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1 hour ago, neilestrick said:

When I was the tech at A.R.T. Clay back in the early 2000's, a rep from one of the big clay suppliers (HC Spinks, I think) stopped in the store to visit, since we bought truckloads of raw materials from them. He was on his way up to Sheboygan, as they supplied tankers of casting slip to Kohler. Anyway, we were talking and somehow the subject of Gertsley Borate came up because this was during the time that it became unavailable for a while, before Laguna started making it again. He was shocked when he heard that potter use it. If I remember correctly he referred to it as 'junk' or possibly something less kind. He said it was so inconsistent that almost nobody in industry would touch it. It was primarily used by the roofing tile industry, but certainly nobody used it in glazes or anything that required precision or consistency. That's when I decided that I would not use it any more.

Gillespie, when substituted directly for Gerstley, tends to be a little bit stronger, and make glazes runnier. I typically start with about 3% less when using Gillespie.

Gerstley borates primary use was to encapsulate nuclear underground tests. Dig a huge hole, put a nuc in the ground, fill the hole with Nearby mined material ..... Gerstley borate! Very popular for potters as a means to get to cone six. When testing stopped (underground nuclear) mining it was no longer cost effective. Potters did not use enough of it. Hence the mine closure. Laguna purchased  the stored material at the site so it's consistency has  been certified by them.  Still plenty of Gerstley in the ground, just no pressing need to mine it though.  

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Thanks for the confirmation there Neil. I actually know of A.R.T. quite well. In the 70's when switching to ^6 from ^06 I found that Amaco, Minnesota Clay and A.R.T. had good ^6 glazes. I had been using Amaco, but 1# bags wouldn't cut it, where as both of the latter two offered 25# bags, and gallon mixed. This helped me to transition into mixing my own in the later 80's. I also attended a workshop at A.R.T. by John Glick .

 

best,

Pres

 

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41 minutes ago, Bill Kielb said:

Gerstley borates primary use was to encapsulate nuclear underground tests. Dig a huge hole, put a nuc in the ground, fill the hole with Nearby mined material ..... Gerstley borate! Very popular for potters as a means to get to cone six. When testing stopped (underground nuclear) mining it was no longer cost effective. Potters did not use enough of it. Hence the mine closure. Laguna purchased  the stored material at the site so it's consistency has  been certified by them.  Still plenty of Gerstley in the ground, just no pressing need to mine it though.  

Very interesting, did not know this part of Gerstley Borate’s history!

My understanding is that when Laguna bought the remaining stock, they put it through a big ball-milling process before bagging it, therefore making it homogenous. Do you know if this is true? I didn’t start using it until after it became a Laguna product, and have found it to be consistent over the years. 

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46 minutes ago, GEP said:

Very interesting, did not know this part of Gerstley Borate’s history!

My understanding is that when Laguna bought the remaining stock, they put it through a big ball-milling process before bagging it, therefore making it homogenous. Do you know if this is true? I didn’t start using it until after it became a Laguna product, and have found it to be consistent over the years. 

I do not know.  In 2011 they put out the memo I posted  above so they appeared to be  committed to some form of continuity.

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missed this thread until today.

pres,  the green glaze i used to use came from the vanGilder book you mentioned.   it is called Oribe and is  the one that will NOT pass the vinegar test so i started looking for another.  moved on to one with barium in it which put everyone in an uproar.   it turned out to be too tender, it would scratch easily so i dropped it    min kindly gave me one that works with many colors and is a very good clear.  

Edited by oldlady
correction

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On 5/10/2020 at 9:35 AM, Bill Kielb said:

Shinos are great but I am a believer in using a liner for functional ware if using Shino so a little less functional but cool. Especially the random surprise that got slightly caught in the rain on your way into the studio. Lots of  cool cone 6 Shino being done at Mudfire pottery.

What failure do you find in shinos for  kitchenware?  Shino is a big category.  For instance Malcolm Davis Shino, if not exposed to excessive carbon is a nice shiny surface.

You're using the term functional to refer to pottery used for food handling purposes, right?

 

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Hi,

I have about 8 that I bought as powder mix and mixed them, two that I mixed myself.  But I discovered Amaco's Potters Choice glazes and I'm in love. They are brushed on unless you buy them powder and make larger batches. Then you can dip them. They are consistent and play beautifully with each other.  There is a great Facebook group I joined, Amaco Cone 5 6 glazes. Check it out!!

I was a teacher, too, for 27 years. Now retired and back in school. Of course!

Nancy

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1 hour ago, CactusPots said:

What failure do you find in shinos for  kitchenware?  Shino is a big category.  For instance Malcolm Davis Shino, if not exposed to excessive carbon is a nice shiny surface.

You're using the term functional to refer to pottery used for food handling purposes, right?

 

Usually their flux ratio is upside down so for me they would need some testing for durability. Easier for me to just use a liner.

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30 minutes ago, neilestrick said:

I think it depends a lot on the shino. I've got a couple of shino cereal bowls that have been going through the dishwasher for 15 years and they still look like new.

Yeah, I believe it. It’s just not worth me testing. I’m sure there are some great ones. but also not so great so it’s not usually worth my time. Mudfire  had an interesting blog (Was the home of  Malcom Davis I was told). When I visited them a couple years ago in the community with all kinds of tested stuff, even cone six. Don’t know If it’s available to the public anymore though.

Edited by Bill Kielb

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On 5/8/2020 at 10:10 AM, Pres said:

Not completely scientific, but enough for me to change my glaze recipes all around.

Definitely scientific!  It doesn't prove a glaze is durable or safe, but it proves one isn't.

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I get the idea shino is a potter's glaze.  If you're in the general public eye, you probably need a palette with blues.  Yeah, I know food looks good on white/black.  Blue is the anti potter color, yeah?

Probably been discussed to death.

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