JDP Posted October 16 Report Posted October 16 Hello all, I'm in the northeastern USA and I've been throwing on the wheel for some time but only ever had access to a low fire kiln. The clay and glazes I could use for that weren't very attractive or durable (at least at the time). I just got mildly used Kiln that can do cone 6 and have been throwing up a storm. The interior dimensions of the kiln are 17"W x 22"H I've read some articles and found some glazes I would like to try...so it's time to buy dry glaze material and I have a list but I'm not sure how much to buy. And places like the ceramic shop often don't list the quantity or units y ou are buying? I don't need to buy tons of the stuff but I would like enough to glaze 5 kiln loads or so. Can anyone look at this list and give me a ballpark of how much I want? If you see anything important I'm lacking or something that should be a diff mesh that would be helpful too. Should I pick up some mason stains as well or is what I have here sufficient to get my feet wet? TIA Nepheline syenite 270 mesh Calcium Carbonate 325 mesh Frit 3134 EPK (Kaolin) Silica Titanium Dioxide Cobalt Carbonate Copper carbonate Iron oxide (Spanish Red) Chromium oxide Tin Oxide Bentonite 325 Quote
Hulk Posted October 16 Report Posted October 16 (edited) Hi Claythrow, Welcome to the Forum! You might price compare including nearby ceramic supply shops* - shipping costs against your time and travel. I've found it well worthwhile to stop in to get clay and glaze supplies, particularly wet clay and larger amounts of material, where I save on shipping and get discount price for larger amounts... If your kiln is rated cone 6 maximum, it may struggle to reach cone 5/6with worn elements. A cone 10 kiln should reach cone 6 for a long while before the elements need replacing. On materials, If you pick a few recipes, then get what's required? For quantity, somewhere between enough to mix a batch** and where the price break is. epk and silica are in everything, I get fifty-pound bags. The colorants, buy when the price is down. The copper and cobalt will go quicker than the chrome (chrome is powerful - read up on that one). I've been using rutile for titanium; I don't mind the bit of color that comes with. Your boron source is frit; you'll be using lots of that. You might end up using a few other frits, depending. Silica, recommended you don't repeat my mistake! Get the finer mesh, 325 *looks like there are several near Worchester There is a supplier in our town, and within a hundred miles there's a clay company that carries pottery supplies as well. Clay ends up costing almost double with shipping. **I do two-gallon buckets. I don't remember how many grams that takes; I'll look and double back later today... added: 4-5,000 grams more than fills a 2 gallon bucket at ~1.4 specific gravity with room to dip medium wares without overflow. Last batch I made was 6k grams, ended up with almost two quarts over ... Edited October 16 by Hulk added Rae Reich 1 Quote
Marilyn T Posted October 16 Report Posted October 16 (edited) This link may prove useful to you. https://suemcleodceramics.com/what-you-need-to-mix-ceramic-glazes/ Edited October 16 by Marilyn T Hulk and Rae Reich 2 Quote
neilestrick Posted October 23 Report Posted October 23 Everything is cheaper in larger volumes, so it really comes down to how much you want to store and how much you want to spend. For some coloring oxides like cobalt you may only want to buy a pound at a time, but for others like red iron you may want to buy 10 pounds or more. A lot depends on how much your recipes use. For EPK, feldspars, whiting, etc, it's going to be cheapest to buy full bags, but that means you'll need to store them. If you have a small studio and don't want to store a lot, I'd figure out exactly what you need to mix all your glazes and buy as close to that amount as possible. Even though you won't be getting the best pricing that way, it'll still be a lot cheaper than buying pre-mixed glazes. Hulk 1 Quote
JDP Posted November 18 Author Report Posted November 18 Ok. so I narrowed it down to this list. Is there anything major I'm missing? Anything I've duplicated somehow? And do the amounts look reasonable? This is my first time down this road. I'm assuming the unit prices on the ceramic shop are in lbs and this totals about $310. If I could lower it that would be good but whatever observation you have would be good. Silica 325 (25lbs) Nepheline Seyelite (25lb) Calcium Carb (25lb) EPK (25lb) Frit 3134 (25lb) Gillespie Borate (1lb) This can be subbed for Gerstley Borate? Bentonite 325 (5lb) Chromium Oxide (1/4lb) Copper Carbonate (1lb $$$$) Iron Oxide Spanish Red (2 lb) Manganese Dioxide 20x40 (1lb) Titanium Dioxide (1lb) Tin Oxide (1/4 lb) Zircopax (1lb) Cobalt Carbonate (1lb) Dave Earley 1 Quote
JDP Posted November 18 Author Report Posted November 18 Also, my kiln has a ramp speed. If firing stoneware should it be 300 degree F per hour? Quote
Hulk Posted November 18 Report Posted November 18 Where the vendor prices break is a factor in my decision making. My guess would be that some/several of your 25lb items would be less $$/lb AND more convenient in the 50 lb sack - assuming you are hauling, for shipping cost can be a BIG factor... Consider also: will price likely rise, fall, or remain constant over the next few years*; how soon will I run out and need more; will the material become unavailable... I'm not seeing a MgO source in your list, an important oxide for mid-fire glazes. I use "Texas Talc" (C-98), which is no longer easily found; there are several alternative talcs, see also dolomite and frits. Copper Carbonate is "cheap" right now, I'd get at least two pounds if ordering today**. Chrome Oxide is same price as Copper Carbonate (today) - a little goes a long way, yes. Still, I'd go with the pound. Zircopax is "cheap" as well. I use it in just one glaze - that could change. epk and silica are in everything; I get fifty-pound bags. I've been using rutile for titanium; I don't mind the bit of color that comes with. Your boron source is frit; you'll be using lots of that. You might end up using a few other frits, depending. If you are hauling, load up on clay while you are at it. Have fun, and please do update on your findings/experience. *generally up, however, some material prices have shot way up, then softened (a lot), e.g. Copper Carbonate and Cobalt Carbonate have been much higher **US Pigment's per pound price is half that of nearby vendor, which easily covers shipping, so. Quote
Hulk Posted November 18 Report Posted November 18 Gillespie Borate (1lb) This can be subbed for Gerstley Borate? Good question. Discussion here: Gillespie Borate ...and here: Gerstley Borate I'll say "very likely" you can make good use of glaze calculation software. I'm using GlazeMaster; there are several other choices. Quote
Hulk Posted November 18 Report Posted November 18 (edited) Also, my kiln has a ramp speed. If firing stoneware should it be 300 degree F per hour? Good question! Slower rate on the final approach (the last 180°F or so) to target recommended. For glaze fire, I'm going 500°F/hr to 1000°F after initial warmup 300°F/hr to 1600 250°F/hr to 2000 112°/hr to 2200 ...then free fall to 2060°F, hold, and finally a controlled cool to 1850°F This firing profile approximates what I was getting with the "old" kiln (an ancient "manual" kiln with worn but still functional element set), except the final ramp; the new kiln heats better, especially the last 100° or so. This is bringing cone 5 down and starting to bend cone 6. The hold helps in "healing over" glaze defects, clearing bubbles, et cetera ...but also adds maybe a smidge of heat work. Edited November 18 by Hulk a note Quote
Bill Kielb Posted November 18 Report Posted November 18 17 hours ago, Claythrow said: Also, my kiln has a ramp speed. If firing stoneware should it be 300 degree F per hour? Good question - to try and nail calculated heat work, best to fire the last segment (last 200 degrees f) near the speed published in the Orton cone chart. Prox 108 degrees per hour (center column) would be typical. Quote
Bam2015 Posted November 18 Report Posted November 18 (edited) From personal experience, I would suggest that you find a glaze(s) that you would like to make and buy the materials for those glazes. Add raw materials as you expand your glaze line. A couple of years ago I purchased pretty much everything that is on Sue's list and now I have multiple bags of raw materials that I haven't opened. But that's just my personal experience and maybe not the right choice for you. Just trying to save you a few $$$. Betty Edited November 18 by Bam2015 Min 1 Quote
C.Banks Posted November 19 Report Posted November 19 Alumina hydrate is a good thing to have around too. Min and Dave Earley 2 Quote
JDP Posted November 19 Author Report Posted November 19 Ty all! I compiled that list based on glazes I would like to try, but being my first time buying them I wanted to make sure the amounts weren't too low or too high. The kiln is in good shape but older, a Gare Perfect Fire 1833 (iirc the model #) It's digital but the ramp rate is linear. I can alter it, but if I choose 300 it's 300 for the first hour and 300 for the last. Hulk 1 Quote
Hulk Posted November 19 Report Posted November 19 The "Soft Fire" feature may be helpful: "This feature slows down the latter portion of the firing automatically and maintains a predetermined time/temperature rate. Its use is recommended for ceramic and porcelain." from: Pfmanual.PDF chosen from: Discontinued 2024 | Evenheat Kiln Looks like Evenheat acquired Gare some time ago... Quote
Kelly in AK Posted November 20 Report Posted November 20 And make sure to buy some cones! Hulk 1 Quote
JDP Posted November 26 Author Report Posted November 26 On 11/19/2024 at 11:32 AM, Hulk said: The "Soft Fire" feature may be helpful: "This feature slows down the latter portion of the firing automatically and maintains a predetermined time/temperature rate. Its use is recommended for ceramic and porcelain." from: Pfmanual.PDF chosen from: Discontinued 2024 | Evenheat Kiln Looks like Evenheat acquired Gare some time ago... Yes, I will use that. For the first hour or two I was thinking of just leaving the peep holes open to slow the ascent, any thoughts? I have plenty of witness cones - 5,6 and 7's Hulk 1 Quote
Hulk Posted November 27 Report Posted November 27 Leaving the peeps open allows water vapor (and later, several gasses - some rather noxious...) to escape, and hence some atmosphere in... ...not sure how much cooling the peeps provide. JDP 1 Quote
JDP Posted December 2 Author Report Posted December 2 When I glaze fire I'll monitor the temps to see how close the "soft fire" feature gets me to the Orton chart. Hulk 1 Quote
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