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Min

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  1. Like
    Min got a reaction from Callie Beller Diesel in Crawling   
    Gums will help with the adhesion of the glaze layers if that is the cause of the crawling but there are other things to look at with crawling glaze problems too. Overall thickness of the glaze layers and also how well the top glaze is bonded with the base glaze are things I would be looking at here too. If there are cracks or lifting of the dry glaze then chances are it will crawl when fired. If you add gum try for the least amount you can to solve the problem. I'ld suggest mixing up a very small test batch of 100 or 200 grams of base plus water plus 1/2% of CMC or Veegum Cer. Try it with the gum in just one of the glazes first then layer the other glaze over it. Dip a few test tiles for the same length of time you dip your pots. (test tiles should be same thickness as your pots and bisque fired the same) Now add some gum to the second glaze (again just a small test batch) and dip some more test tiles. Get the second coat of glaze onto the test tiles as soon as the wet sheen is gone and you can handle the pots. Don't wait for the base glaze to dry all the way. Glazes with gum will take longer to dry so using the least you can is a good idea. If the 1/2% isn't enough then double it and try again, it might take up to 2% gum. Decreasing the water content of the glaze sometimes helps with thin walled pots too.
    Since you are using commercial glazes we can't look at the recipes for those and adjust clay content etc.
    If you can get a product called Magma in the UK then I would try that, if not then try either CMC or Veegum Cer.
  2. Like
    Min reacted to neilestrick in Designing glaze blends for colors   
    I like a big triaxial blend when doing color tests. You get line blends along the sides and tri blends through the middle. The bigger the better if you want to get close on the first try. Hyperglaze has a section in the software called Potter's Friend that allows you to put in the percentages of the colorant for each corner of the tri, then it gives you a list of what goes into each tile. It has a nice 66 tile blend that gives you a ton of color variations. If you don't have access to Hyperglaze or some other program that simplifies the process, I'd be happy to plug in your stuff and post the charts here for you. I just need to know the percentage of each ingredient you want at the corner. Attached is a sample of a 66 tile blend with (1) 0.5% cobalt carbonate, (2) 3% copper carbonate, and (3) 4% rutile at the corners.
    66 Tile Triaxial.pdf
  3. Like
    Min reacted to Callie Beller Diesel in Designing glaze blends for colors   
    Biaxial and triaxial blends are great for fine tuning colours, for sure. If you do an initial biaxial blend to figure out intensity of individual colourants, you can then start mixing them together to fine tune the shades you want.
    Use a light hand with the nickel, and keep it out of firings with mason stains you don’t want to shift the colour of. There’s a fine line between muted and muddy with that stuff. The only reason I don’t say leave it out entirely is because you want grey.
    Blues and greens are pretty easy to achieve. If you want pinks and purples, you can play around with chrome tin pinks, but I’ve had great success with mason stains. If you want a sunshine yellow, you definitely want a mason stain.
  4. Like
    Min reacted to ThruTraffic in How Much Grog to Wet Clay for Raku   
    I haven’t, even though I do have some. I just got started with Raku so wanted to do all my learning curve stuff with some reclaim I have which is a scrap mix of B-mix 5 w/wo grog, some Buncombe and other ‘whites’. There’s not a lot of b w/grog in it. So far what I’ve used without adding grog has done well with few cracks; only one explosion so far. 
  5. Like
    Min got a reaction from Callie Beller Diesel in How Much Grog to Wet Clay for Raku   
    Sounds about right, depends on how quickly you are heating and cooling the pots etc. Fine or medium grog? If you guesstimate the wet clay having around 20% water you will be a bit over your 20% grog target but it should be close enough. Have you tried cut and slam wedging to get the grog mixed in? Video below if you need it. When I've added grog (or sand) to clay I make a rough block shape with the clay, slice it up and sprinkle the grog on each layer then slam them together. Add water with a spray bottle as you need. Once the grog is layered into the block then do the slice and slam wedging to get it mixed in. 
    https://youtu.be/HApNjUnI9U4
  6. Like
    Min reacted to Bill Kielb in Potter's Choice True Celedon 5 Gallon Clumping Issue   
    Maybe someone with direct experience will answer but since this is a commercial glaze we have no idea of how much clay it might contain and if it is naturally deflocculated due to sodium. I suggest a good read for this  https://suemcleodceramics.com/how-to-fix-a-hard-panned-glaze-with-epsom-salts/
    You likely will end up using Epsom salt a little at a time to re suspend the glaze. Since bentonite can generally be added up to 2%, you might settle on 1% addition because you will never know the actual clay content, then flocculate with minimal Epsom salt as a start.
    Hopefully someone has direct experience with this commercial glaze for a tried and true solution. Actually a call into Amaco probably gets you the most tried and true solution for this glaze. I am sure they have seen it before.
  7. Like
    Min reacted to neilestrick in Just out of high school   
    All knowledge is good and will help you with your art, so even those non-art classes will be a benefit in the long run. I started college as a math major and ended up with an art degree with an emphasis in ceramics and photography. I use my math skills all the time, both in my ceramics work and in running my business. The sociology and psychology classes I took help me in dealing with customers and students. The science classes help with the technical aspects of clay and glaze development. Art is a reflection of life, so the more you know the better your work will be. It can definitely be a bit of a drag at times having to take non-art classes, but they will make you a more well-rounded person. Plus you'll have some skills that can help you earn money as you're getting started in your art career, or if things get tough (like during a pandemic). So give it a chance before you make any big decisions. It may also be that your school just isn't a good fit for you. But it takes more than 3 weeks to figure that out. Finish out the semester and reflect on it before making any changes.
  8. Like
    Min reacted to Callie Beller Diesel in Glaze making empty round circles   
    @lin_c I think the spots are coming from an impurity of some kind, because there’s a black speck right in the centre of each. The usual place to look for something like that here would be the clay body. If the impurity is silica or feldspar of some kind, it could explain why the spot is glassy instead of bare. One way of testing that theory would be to try the glaze on a different clay.
  9. Like
    Min reacted to Piedmont Pottery in Dealing with wollastonite lumps   
    A quick nonquantitative trial of sucralose vs. wollastonite.  I had two 1kg test batches of glaze with the same base glaze formula, different colorants in each, but the same amount of wollastonite.  Each was added to approximately 120 ml water, 2 g of sucralose was added to one, and each was allowed to slake for about 2 hours with frequent mixing, then filtered through a small sieve.  The image on the left below (or top, depending on your browser) is the residue from the one with sucralose, while the one on the right (or bottom) is without sucralose.  Visually,  although difficult to tell from the photos, the glaze with sucralose appeared to have about half as much wollastonite agglomerates on the filter as the one without.  In each case, the aggregates could be dispersed through the sieve with gentle pressure from a silicone spatula, but the sucralose sample dispersed more readily.  Based on this quick and dirty trial, it seems like it will be worth while to repeat this a bit more rigorously.  I have to admit I was surprised by the apparent effect of sucralose, as I wasn't expecting to see much difference with this test. 


  10. Like
    Min reacted to GEP in Do I need a gas kiln?   
    My advice is to not get a new kiln just for one glaze. At 4 years in, you are still somewhat new to pottery, and your interests in glazes may still be evolving. 
    When I was younger, I was convinced that I would someday build a wood kiln, because I loved the aesthetic and thought there was nothing as good. As I got older and became a more knowledgeable potter, I outgrew that. I still love the aesthetic and admire those who do it, but am very happy doing electric kiln work.
    At 4 years in, your focus should be on improving your forms and pottery building skills. A lot of potters at this stage (including me back then) place too much importance on glazes and firings, thinking that this will elevate their pots to a higher level. But really a glaze cannot do that. And when your pottery building skills have reached a high level, any glaze and firing will elevate your pots. 
  11. Like
    Min reacted to neilestrick in Do I need a gas kiln?   
    I moved the other way, from gas to electric. I think that's pretty common nowadays what with the limitations on where you can set up a gas kiln nowadays. I could have continued to do gas, but there were numerous benefits to switching to electric, which together far outweighed my need to fire shino and tenmoku glazes.
    Oxblood can be done very well in an electric kiln, using silicon carbide for localized reduction. Shino not so much. I've yet to see a convincing electric kiln shino or tenmoku. None of the commercial glazes they call shino are at all close to the real thing. So if you want to do shino, then yes, you'll need a gas kiln. Are there any potters or community studios in the area that have a gas kiln that you could use just for that, and keep using the electric kiln for everything else you're doing?
    If your'e also looking for that earthy, iron-specked look of reduction fired work, then get a good cone 6 brown speckled body and find some glazes that will play well with it. They're virtually indistinguishable from cone 10 reduction when done right.
  12. Like
    Min reacted to Pres in Just out of high school   
    Jack, Welcome to the forum.
    I would say that at this point, it is just too early to know, give it a semester and see what happens. When I say give it a semester, I mean put your heart and head into everything you do. This of course is IMHO, but I spent many years in education teaching at HS, summer camps and College levels. First semesters are rough in a lot of ways.
     
    best,
    Pres
  13. Like
    Min got a reaction from Chilly in Glaze Flaking off   
    @tzylawy, I'm copying the image you posted in the gallery into this thread so it's easier to find.
    Definitely wouldn't fire this as is. Was the glaze frozen at some point or is it really old? Also did you really stir it up before using? Did your brush drag as you were applying the glaze? Reason I'm asking is it looks like the gums that are typically used in brushing glazes are no longer effective. Is that the same glaze on the inside of the pot?
    I'ld scrape off as much glaze as you can (wear a mask), dump it back into the jar and scrub the outside of the pot. I'ld then add a little bit of gum solution and enough water to make a good brushing consistency and try it again on a test tile. If it works on the test tile then reglaze your pot. (it's easy to make your own gum solution if you don't want to buy it)
    Welcome to the forum 

     
  14. Like
    Min got a reaction from Callie Beller Diesel in The last show in the desert   
    Really sorry to hear this Pres. Best wishes for a speedy recovery when she gets her surgery.
  15. Like
    Min reacted to Babs in Glaze making empty round circles   
    800C quite a low bisque, prob too low
    More usual to bisque cone 04 1060degC or cone 06  1000degC.
    Not sure if this will affect the result. Are all the circles in the inside of pots?
    Wipe your pots with a damp clot befire glazing.
    A 30 min soak will bring the heatwork done  to way over 1170 in my op.
    Very frustrating for you
  16. Like
    Min got a reaction from Roberta12 in Glaze Flaking off   
    @tzylawy, I'm copying the image you posted in the gallery into this thread so it's easier to find.
    Definitely wouldn't fire this as is. Was the glaze frozen at some point or is it really old? Also did you really stir it up before using? Did your brush drag as you were applying the glaze? Reason I'm asking is it looks like the gums that are typically used in brushing glazes are no longer effective. Is that the same glaze on the inside of the pot?
    I'ld scrape off as much glaze as you can (wear a mask), dump it back into the jar and scrub the outside of the pot. I'ld then add a little bit of gum solution and enough water to make a good brushing consistency and try it again on a test tile. If it works on the test tile then reglaze your pot. (it's easy to make your own gum solution if you don't want to buy it)
    Welcome to the forum 

     
  17. Like
    Min got a reaction from Bill Kielb in Glaze Flaking off   
    @tzylawy, I'm copying the image you posted in the gallery into this thread so it's easier to find.
    Definitely wouldn't fire this as is. Was the glaze frozen at some point or is it really old? Also did you really stir it up before using? Did your brush drag as you were applying the glaze? Reason I'm asking is it looks like the gums that are typically used in brushing glazes are no longer effective. Is that the same glaze on the inside of the pot?
    I'ld scrape off as much glaze as you can (wear a mask), dump it back into the jar and scrub the outside of the pot. I'ld then add a little bit of gum solution and enough water to make a good brushing consistency and try it again on a test tile. If it works on the test tile then reglaze your pot. (it's easy to make your own gum solution if you don't want to buy it)
    Welcome to the forum 

     
  18. Like
    Min reacted to PeterH in Glaze cracking boiling water   
    From Bisque Direct's mug page https://bisquedirect.com/bisque/mugs.html
    Earthenware Clay - Glazing and Firing.
    The recommended glaze firing temperature is 1000˚C to 1080˚C and soak (hold) 30 minutes + for all our Earthenware bisque items.
    For tableware items firing 1030˚C to 1080˚C produces a more durable product.
    Which is repeated on their dipping glaze page https://bisquedirect.com/glaze/clear-gloss.html
    They offer three glazes all firing "Approximately cone 06 to 05." Also gives Bullers ring ranges for each glaze.
     
  19. Like
    Min reacted to Clay Dragon in Why make functional ware?   
    "I am a functional potter making everyday life a little more beautiful" is my business description. When I came across the question, "Why make functional pottery?" I laughed. I make my functional pottery, go to markets, sell, sell, sell, then I go back to my pottery studio and make more. I enjoy making functional pottery and my customers enjoy buying functional pottery. It's a good business. Obviously there are a few people that ask questions like this. To be honest at sixty years old I have not met one. So I say the the majority, "Thank you".
  20. Like
    Min got a reaction from Roberta12 in Underglaze pinholes and flaws - I don't understand why?   
    Re the debate of a refractory underglaze or not it would be fairly simple to test this theory without altering glaze recipes. Since we know adding flux will make things less refractory and adding alumina the opposite, using this logic I'ld run 2 parallel tests, one adding flux, Gerstley Borate should be a good choice, and the other adding calcined kaolin.  Say roughly 1 Tablespoon liquid underglaze + 3/4 teaspoon of Gerstley Borate or calcined kaolin plus enough additional water to make them brushable. Apply to both a vertical and horizontal surface with the same number of coats and fire them both the same and see what comes out of the kiln. 
  21. Like
    Min got a reaction from Roberta12 in Underglaze pinholes and flaws - I don't understand why?   
    Lovely that you found a solution that works for the potters in your studio but from reading the original post from @carolrossit sounds like she is using a commercial brushing glaze. I think we need to work within the parameters of the the op's usage insofar as commercial versus studio mixed glaze.  Like many things in ceramics there are times we can make things more complicated than they need to be. 
  22. Like
    Min got a reaction from Callie Beller Diesel in pink glaze   
    - Cobalt will make a purple to purplish to bluish colour with magnesium but the magnesium level needs to be quite high to really get the purple tones. I don't think 3% magnesium carbonate will get it high enough. If you are glaze testing anyways you might as well try it, I'ld try 0.2 up to 0.5 cobalt carb. Just do a progression blend, they are fast.
    - Chrome + tin can make pink if the base glaze is very high in calcium. These glazes typically are also on the low side with magnesium and alumina.  For doing test batches a really accurate scale is necessary, especially for the chrome. If you just want a general idea if this base glaze will work then skip the blends and just try 0.20 chrome oxide + 6.0 tin oxide and if you get a red tone you will know if this base supports chrome:tin pinks / reds. If you get pink / red then work on the cobalt to shift the colour.
    - I would also try it as is with the manganese dioxide. Pinks can be made with high alumina glazes + manganese. 
    - You can get pinks from rutile, with and without tin but it's easier to supply the chrome from chrome oxide rather than the trace amount in rutile. 
    - If you do try the chrome / tin be aware that having chrome in the kiln can flash nearby pots containing tin to pink.
    - How much of this glaze did you mix up? Is it in liquid form now?
    Welcome to the forum 
     
  23. Like
    Min got a reaction from Callie Beller Diesel in Underglaze pinholes and flaws - I don't understand why?   
    Lovely that you found a solution that works for the potters in your studio but from reading the original post from @carolrossit sounds like she is using a commercial brushing glaze. I think we need to work within the parameters of the the op's usage insofar as commercial versus studio mixed glaze.  Like many things in ceramics there are times we can make things more complicated than they need to be. 
  24. Like
    Min got a reaction from Callie Beller Diesel in Underglaze pinholes and flaws - I don't understand why?   
    Before doing more work I'ld run some tests with thickness / number of layers. 5 coats seems excessive. Have you tried Spectrum Black 515? I use it watered down and 2-3 fairly thin coats for solid coverage. (it's on the bowl below)
    If there is dust on your pots if possible try using compressed air to blow it off before glazing if you don't need to wet the bisque. This might be another thing to test, unwashed, wiped with a clean sponge, compressed air, dipped in water etc. 

     
    EDIT: I'm going to edit the title of this thread to better reflect it's contents. Going forward it will make it easier to find it when doing a search.
  25. Like
    Min got a reaction from Callie Beller Diesel in Ikea trying for handmade aesthetic   
    The point that bothered me the most was equating "embracing a mistake" with being handmade and unique. 
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