Bill Kielb Posted January 21, 2019 Report Share Posted January 21, 2019 37 minutes ago, neilestrick said: From Digitalfire: Gerstley Borate is also very plastic and thus suspends and hardens glazes as they dry. In fact, few clays have the plasticity and the ability to retain water that GB has. A GB slurry can take many hours to dewater on a plaster batt, even in a very think layer. Thus it is common to find Gerstley Borate based recipes having no clay content. I'm not suggesting that Gerstley should be added to anything as a suspender, because it would obviously have other effects on the glaze, but at 35% it will definitely have suspension qualities, and therefore the 5% EPK in the glaze probably isn't an issue. My last attempt at this and just my opinion. Add bentonite (up to 2%) for recipes without sufficient clay to keep your glaze suspended. Limit your boron to about .5 no more even for cone 04 stuff. And finally she has a high percentage of Gerstley already so I am not sure where we are going with this. I mentioned bentonite because some of the previous posts speculated the recipe was not suspended. Mentioning Gerstley as a suspender in my view is not all that productive. just my opinion though so it’s worth the cost charged. Link to comment Share on other sites More sharing options...
neilestrick Posted January 21, 2019 Report Share Posted January 21, 2019 @Bill Kielb You had said that Gerstley is not a good suspender. I was not meaning that bentonite is not. Sorry for the confusion. Link to comment Share on other sites More sharing options...
Grace london Posted January 21, 2019 Report Share Posted January 21, 2019 This recipe is from a ceramic technician at a large uni in Canada...It is also listed here on glazy https://glazy.org/recipes/1966 Link to comment Share on other sites More sharing options...
Grace london Posted January 21, 2019 Report Share Posted January 21, 2019 It is used for sculpture 04. It is a nice matt that just works for me. I am of course willing to improve it. A lot here to take in so I will make notes and report back. Will experiment with the Bentonite. I also add these for variations: Zircopax 10 Tin 10 Titanium 10 Black Velvet stain 15 Copper ox 5 Cobalt ox 5 You can see here in this head below, I layer the glazes, and use wax to inlay .It's an effect I like. Thank you all for your expertise , G Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 21, 2019 Report Share Posted January 21, 2019 Nice work! I’ll see if I can conjure up a very dry flat lithium matte tomorrow in the studio. One With better theoretical chemistry. No guarantees but it would be something you could then experiment with and hopefully be easier to maintain. The only different additional ingredient I can think of that I might use is a small amount of wollastonite. again,, very striking work! give me a couple days to mix and fire so at least I can send the recipe and some close up pictures don't worry about the addition to 95, I see many recipes that add up to less or more as folks have done the math by hand over the years. Link to comment Share on other sites More sharing options...
Grace london Posted January 21, 2019 Report Share Posted January 21, 2019 32 minutes ago, Bill Kielb said: Nice work! I’ll see if I can conjure up a very dry flat lithium matte tomorrow in the studio. One With better theoretical chemistry. No guarantees but it would be something you could then experiment with and hopefully be easier to maintain. The only different additional ingredient I can think of that I might use is a small amount of wollastonite. again,, very striking work! give me a couple days to mix and fire so at least I can send the recipe and some close up pictures don't worry about the addition to 95, I see many recipes that add up to less or more as folks have done the math by hand over the years. Wow, thanks very much Bill. Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 21, 2019 Report Share Posted January 21, 2019 Wonderful Artisty, I love it! Thanks! Link to comment Share on other sites More sharing options...
neilestrick Posted January 21, 2019 Report Share Posted January 21, 2019 4 hours ago, Grace london said: It is a nice matt that just works for me. I am of course willing to improve it. A lot here to take in so I will make notes and report back. Will experiment with the Bentonite. You only need the bentonite if you're having suspension problems. It won't help with crystallization. If the glaze works for you, then go with it. You don't really need to change anything if you're not using it on functional pieces. Reformulating may help with crystals, though. Love those heads! Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 22, 2019 Report Share Posted January 22, 2019 On 1/21/2019 at 6:13 AM, Grace london said: Wow, thanks very much Bill. Just a quick update, I picked two recipes to do a silica progression on. One is durable and reduces your lithium while adding magnesium by way of Talc to see if you like a durable composition (R2O of between 0.2 and 0. 3). The second is basically artistic and attempts to mirror your lithium apportionment To maintain the color influence that you are familiar with. both recipes simply seek to move this from a very undefined underfired recipe to a true matte chemistry. The silica progression we do here should help dial in a level of matte. Expect to mix today along with some other tests and fire within a couple days. no guarantees and first recipes usually point towards adjustment for the next round of tests. just thought I would update you on the progress. Link to comment Share on other sites More sharing options...
Min Posted January 22, 2019 Report Share Posted January 22, 2019 @Bill Kielb, it's good of you to work on this for Grace. Just an idea but you might want to supply the lithia from spodumene rather than lithium carb to reduce the crystal formation problem she was having as spodumene isn't nearly as soluble as lithium carb. Chemistry is very close to your 2 recipes above. Your recipe 1 could then be: GB 42.4 Nep Sy 9.9 Spodumene 47.7 total 100 Your recipe 2 could then be: GB 40.9 Talc 8.4 Silica 1.2 Epk 25.2 Spodumene 24.3 total 100 (The LOI is lower on this than your version of it but it's still very high, I would be concerned with offgassing.) Also, I feel we have gone off track from the original post and the title of this thread, I'm going to start a new one in the Chemistry section titles Jackeeze Matt Alterations. Link to comment Share on other sites More sharing options...
Bill Kielb Posted January 22, 2019 Report Share Posted January 22, 2019 Yes, spodumene better but I committed to trying to stick mostly with the chems she has in stock. We will make a spodumene version at some point I suspect, it will take a bit of thought, or maybe not - you did it! The LOI at this point is an efficiency thing and may or may not be an off gas concern. Epk, Gerstley, silica, and talc, pretty simple. Not a whole bunch to this but we will see if she likes a recipe that is a true matte or if the underfired thing is the winner. Three goals at this point, get some clay in this, get this on the map and keep the sodium low while using her stock chems. oh almost forgot, want to leave her some matte adjustability by way of sliding silica up and down. Link to comment Share on other sites More sharing options...
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