Jump to content

Hulk

Moderators
  • Posts

    2,217
  • Joined

  • Last visited

Reputation Activity

  1. Like
    Hulk got a reaction from LeeU in The Pottery of Sound   
    I do like water.
    A few years ago I tried for a fountain, driven by a small pond pump.
    Credit the FDR Memorial (Washington, DC) fountains, in part, for positive inspiration, a neighbor's drop-in pool kit for negative inspiration.
    The former, a variety of water sounds, each fountain different, each pleasing; the latter, a solid stream, not so pleasing.
    I wanted a soft drip, hence, the water flows over the inverted cone shape, falls a short distance (.8 to 1.2") to the tower base, then another inch or so to the reservoir, producing a gentle gurgling murmur.
    The pump is concealed between the base and tower, wrapped in foam to dull the humming.

  2. Like
    Hulk got a reaction from pottery007 in The Pottery of Sound   
    I do like water.
    A few years ago I tried for a fountain, driven by a small pond pump.
    Credit the FDR Memorial (Washington, DC) fountains, in part, for positive inspiration, a neighbor's drop-in pool kit for negative inspiration.
    The former, a variety of water sounds, each fountain different, each pleasing; the latter, a solid stream, not so pleasing.
    I wanted a soft drip, hence, the water flows over the inverted cone shape, falls a short distance (.8 to 1.2") to the tower base, then another inch or so to the reservoir, producing a gentle gurgling murmur.
    The pump is concealed between the base and tower, wrapped in foam to dull the humming.

  3. Like
    Hulk reacted to Mark C. in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    I use the slip from my hands throwing medium and larger forms. I keep in in tall plastic open container with a piece of light plastic over it. If it gets thick we add  a splash of vinegar. Sometimes no vinegar for months.  Thgis slip is always teh same body we are working with and water is not added. I also collect from splash pan if needed quickly, gthge thicker stuff .Never bothered about magic-I learned ceramnics before those concepts where born and never needed them so never thought about doing them later. Now I will add we handle thousands of mugs every year in porcelain and getting the handles on same day is the norm with the clay all the same moisture content. Handles,  on then cover with loose light plastic sheets that night uncover and let dry. If any small cracks appear I use a thin wood stick to rub them out while loading them in bisque kiln. (pro tip I leaned from another potter in the 80s) then they never show up again. Also if you do this while loading that saves handling them another time which is all about time saving which is what am all about with clay.
  4. Like
    Hulk reacted to pottery007 in The Pottery of Sound   
    Oh my gosh you guys! I was not expecting anyone to be responding to my questions because I thought it would easily get lost. Opened the forum today and I'm seeing all of these comments and learning so much from you all. Thank you so much for taking the time and commenting over here. I've been carrying out a lot of my research based off of Instagram and Pinterest looking through works by various artists and how that connects to their audience. It has started to get very interesting. I will be sharing all that I've learned as things progress forward. It is going to take me some time to read through all of the comments and since it is late here in Melbourne and I'm sleepy I can't comprehend everything, haha! But I shall be back here tomorrow! Thank you so much once again! I'm so very happy! Thank youuu!!
  5. Like
    Hulk reacted to Jarman Porcelain in Warped rims on my porcelain sculptures   
    I made a body of sculptures out of porcelain paper clay that were somewhat similar. I was using a translucent cone 6 porcelain and firing to cone 8. To prevent them from collapsing in the kiln I made a rudimentary saggar that I placed them into, then filled the void, as well as the piece, with silica sand. This went about half way up the side, I stabilized the "handles" at the top by rolling up some fiber blanket into a tight tube and running through each loop. For more complex shapes you can use kanthal wire to bind rolls to each other. Make the saggar (maybe armature is a better word?) out of cone 10 raku clay or fire clay so you can reuse them forever. 

    Good luck, those pieces look great already.

  6. Like
    Hulk got a reaction from LeeU in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    What
    Attachments (in my experience, err, limited experience), almost always one piece is damper than the other.
    The drier bit, I'll pick up half a drop of water with my finger and wet the attachment point - not enough to run, enough to impart a sheen that dissipates as the water is absorbed - add another half drop, as required (credit Ingleton potter Dick Unsworth's teapot process video).
    The wetter bit, I might dampen just enough to bring up a sheen, then score it in two crosses* (like UK flag), pile on a blob of slip, score the pre-dampened landing spot (in no particular pattern), dampen it a touch more, then get to attaching. I don't mind if it slides a bit at first, for it tightens up considerably as the moisture dissipates into the surrounding (dryer) clay.
    For shallow angles, like the top portion of a mug handle's lower attachment, I roll a small coil (2-3 mm, if that), cut to length, wet it, set it aside. After all ends are attached, I'm brushing a bit of slip in there, placing the coil, then smooshing it in. The edge of a loop tool fits in there. A damp brush can help. I don't remember where I saw this, perhaps a Pinnell video clip.
    ...now I do the same on the top attachment as well.


    Why
    Variations on what we were shown in Wheel I class.
    There was talk of vinegar and "Magic Water" - I was curious; what is magic water**, how does it work, what are advantages & drawbacks?
    I was curious, but not enough to dig into it, for my attachments were much less a problem (at that time) than so many other things!
    Adding the tiny coil, well, the radius can be achieved by other means, shaping the end, for example (credit Simon Leach video clip).
     
    * The slip squeezes out along the score lines.
    Nah, but that was the idea, which is now habit.
    **Here's an article and recipe:
    Magic Water (ceramicartsnetwork.org)
     
  7. Like
    Hulk reacted to Roberta12 in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    Magic water. That is how I was trained.  But I think I may try @Min idea of magic water with slip for my porcelain handles.  
  8. Like
    Hulk reacted to Min in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    I've been using slip made with magic water and my dry claybody for years. I use a smooth white claybody and fire to cone 6. I think it makes a difference which claybody is being used, some are far more prone to handles etc popping off than others.
    Magic water helps as the slip made with it is stickier than made with just water, it dries harder than plain slip and during the firing the extra sodium in the slip helps flux the slip a little more than plain slip making a stronger join post firing.
  9. Like
    Hulk got a reaction from Roberta12 in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    What
    Attachments (in my experience, err, limited experience), almost always one piece is damper than the other.
    The drier bit, I'll pick up half a drop of water with my finger and wet the attachment point - not enough to run, enough to impart a sheen that dissipates as the water is absorbed - add another half drop, as required (credit Ingleton potter Dick Unsworth's teapot process video).
    The wetter bit, I might dampen just enough to bring up a sheen, then score it in two crosses* (like UK flag), pile on a blob of slip, score the pre-dampened landing spot (in no particular pattern), dampen it a touch more, then get to attaching. I don't mind if it slides a bit at first, for it tightens up considerably as the moisture dissipates into the surrounding (dryer) clay.
    For shallow angles, like the top portion of a mug handle's lower attachment, I roll a small coil (2-3 mm, if that), cut to length, wet it, set it aside. After all ends are attached, I'm brushing a bit of slip in there, placing the coil, then smooshing it in. The edge of a loop tool fits in there. A damp brush can help. I don't remember where I saw this, perhaps a Pinnell video clip.
    ...now I do the same on the top attachment as well.


    Why
    Variations on what we were shown in Wheel I class.
    There was talk of vinegar and "Magic Water" - I was curious; what is magic water**, how does it work, what are advantages & drawbacks?
    I was curious, but not enough to dig into it, for my attachments were much less a problem (at that time) than so many other things!
    Adding the tiny coil, well, the radius can be achieved by other means, shaping the end, for example (credit Simon Leach video clip).
     
    * The slip squeezes out along the score lines.
    Nah, but that was the idea, which is now habit.
    **Here's an article and recipe:
    Magic Water (ceramicartsnetwork.org)
     
  10. Like
    Hulk reacted to twsincich in First Wood Fired Kiln Build, Problem Stalling   
    The pieces came out really well, especially since this was only my 4th time firing a kiln and first time slip casting anything! I made a cone 10 stoneware body and a cone 10 porcelain body to cast with and made 16 new cone 10 glazes to test out as well. So I definitely risked all my marbles that I'd be able to get the kiln up to temp! Everything in the very front split apart which I am assuming because it was directly near the burning wood and sometimes the wood did hit the pieces. So that is an easy lesson to fix. I'm thinking maybe some kind of bag wall of bricks would help? Ideally I would probably want the firebox and grate to be much lower to prevent this but without a huge rebuild I'm hoping I can figure something simpler out. Everything behind those fired wonderfully! 
     

     
    and some glaze testers 

     
  11. Like
    Hulk reacted to twsincich in First Wood Fired Kiln Build, Problem Stalling   
    As for the firing itself, I started much earlier than previous firings to give myself plenty of time and options to be patient and learn the kiln. After blowing up so many pieces being in a rush last time I let everything dry for a few days after finishing glazing and let it all candle with a heat lamp in the kiln for another day. Started the fire at 10am and wanted to hold it under 200 deg F for at least 2 hrs to make sure everything was as dry as it was going to get. Then I slowly starting to increase the temp until I hit around 500 deg F and then followed my usual climb rate of about 150 deg every half hour. No particular reason for 150/half hour but my first fire followed that and it seems to work. This was all done by simply using little cedar shake strips burning in the air intakes. After i hit 500 I started to put a piece of my cut 2x3x14" pine pieces onto the fire grate and would used splits pieces of those to stoke the air intakes. This rhythm of putting the full piece on the grate and then using split pieces in the air intakes seemed to work well to regulate the climb and get the wood to burn all the way down efficiently. Once I got to around 1800 deg F I started putting the single pieces onto the grate and there was a sufficient coal bed to burn the wood without stoking the air intakes with split pieces. After about 2000 deg F the climb started to slow down and I started to test different damper, air intake stoke and wood addition ratios. I learned that keeping the air intakes clear and allowing the coal bed to burn down allowed the wood to burn quicker. (I'm assuming because it was hot enough and more air intake) I also realized that instead of using full 2x3x14" pieces, if i split them into 3 or 4 pieces and added them onto the fire grate more often they burned quicker and the temp climbed easily. I was easily able to get to 2394 deg F (but NOT 2400 haha and I used a lot of wood and time to try to get there) At top temp I closed the chimney damper all the way and bricked up the kiln. I am fairly confident I can get it up to temp quicker and more efficiently than this time, with less wood now that I have gotten familiar with the kilns habits. 
     

     

  12. Like
    Hulk reacted to twsincich in First Wood Fired Kiln Build, Problem Stalling   
    @Kelly in AK @Russ @neilestrick @Biglou13 @C.Banks
     
    Hello to all who have posted help, just wanted to give an update since my most recent kiln firing with your suggested modifications. Thank you again SO MUCH for your kind words, advice and encouragement! 
    I am happy to report that I believe the firing went very well! I was able to fire the kiln up to a top temperature of 2394 deg F and the cone 10 on my cone packs in the front and back were completely bent. I think I may have even gotten to cone 11 in the very front but do not have cones for 11 so more of a guess. Started the fire at 10am and bricked up the kiln and closed the chimney damper all the way at 12:30 am for a total fire time of 14.5 hrs, which I am very happy with.
    What took so long? Well, I thought if I learned slip casting I could fill the kiln up quicker for another firing to test the modifications but of course that took a few months longer that planned. 
    The modifications I made were:
    1- Enlarged the exit flue to almost double the size it once was. Drilled small holes along the line I wanted to cut and then used progressively larger bits until the block fell right down. Not very pretty but perfectly functional and my major concern was cracking the pieces of brick left, so, success there. 



     
    2- Rebuilt the fire grate with 1 1/4" rebar and T bar steel that I picked up from the local junkyard. Little slump in the front (I'll add a support brick in the middle next time) Worked great as a cheap, replaceable fire grate that raised the wood up about 5 inches from where it was last time and opened up the coal pit area under it significantly. I could tell when I was firing that the coals superheated the wood, which burned better and faster and I only cleared out the coal bed minimally this time whereas the previous firings I would have to constantly rake out the coals once I hit 1900 deg F and would end the firing with a large pile of coals on the ground after. 


    How many firings will it last? I don't know but easily and cheaply replaceable. 
    3- Opened up the air intake space in the kiln door to allow more air in. As the coals seamed to burn down better and faster and the kiln seemed to draw well the entire firing, this seemed to help a lot in connection with the raised fire grate. 

     
    4- Insulated the chimney more up to the damper. I didn't have as many soft bricks as I thought so I just used a mix of hard and soft for this firing with some simple fireclay/sand mortar to see if it worked before I did anything more substantial. (I have to drive 3 hours to Portland for firebricks/clay/most things I need) Seemed to help! There was always a strong pull in the kiln and flames shooting up when I would stoke. 



  13. Like
    Hulk reacted to Beccap in Chrome & Zinc - toxic?   
    Yes I think when I started using 1% chrome I didn’t realise the dangers associated with it, and then looked it up and read the type that potters use is not the super scary harmful one. My over thinking brain has maybe thought in the presence of zinc, if chrome turns brown - is that chemically altering it to something that is toxic? And I can’t see it because there is also cobalt & rio so the colour change is not there? I think I am possibly overthinking the combination of zinc and the use of chromium oxide….

  14. Like
    Hulk reacted to Dick White in Chrome & Zinc - toxic?   
    As others have already noted, neither zinc oxide nor chrome oxide used in reasonable amounts in a stable glaze are toxic. A different issue arises when both are used together in the same glaze - ugliness abounds. Chrome is supposed to be green when in a glaze that does not contain tin. A combination with tin in the right amounts creates a variety of pinks and reds. Zinc with chrome, however, turns assorted shades of brown, when copious amounts are used. It won't hurt you, but you probably don't want to look at it. Perhaps your glaze recipe doesn't have enough for the adverse color reactions.
  15. Like
    Hulk reacted to Min in Chrome & Zinc - toxic?   
    Let's not throw the baby out with the bathwater here. The form of chrome used makes all the difference in the world in regards to toxicity.
    Potters use chrome oxide, it is insoluble in water and gets bound in the glaze matrix in a balance glaze. It is volatile in the kiln so it can cause a pink blush on tin white glazes. Wear gloves if you get contact dermatitis with it. (it's a good idea to wear gloves whenever handling raw materials and glaze slurries to avoid skin reactions)
    We do not use the exceedingly dangerous hexavalent chromium in ceramics. Iron chromate is toxic, stay away from using it.
    Zinc oxide fumes from kiln firing shouldn't be breathed in, zinc can become volatile above around 850C/1560F and like all the materials we use in glazes practice good studio hygiene and wear a respirator while handling dry materials. In a glaze it isn't a problem. 
    Chrome + tin pinks and reds are perfectly safe, whether in a stain or from the oxides.
     
     
     
  16. Like
    Hulk reacted to Rae Reich in Tips for multiple coats of paperclay slip   
    I wonder if some of your breakage during firing is due to the irregular shapes of the branches, so that they do not rest their weight equally on the points of contact with the shelf. Maybe a shallow, silica sand filled tray to nestle them in so that they’re resting on the sand all along their lengths?
  17. Like
    Hulk reacted to Cylena in Tips for multiple coats of paperclay slip   
    Couple of close ups
     


  18. Like
    Hulk got a reaction from Rae Reich in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    What
    Attachments (in my experience, err, limited experience), almost always one piece is damper than the other.
    The drier bit, I'll pick up half a drop of water with my finger and wet the attachment point - not enough to run, enough to impart a sheen that dissipates as the water is absorbed - add another half drop, as required (credit Ingleton potter Dick Unsworth's teapot process video).
    The wetter bit, I might dampen just enough to bring up a sheen, then score it in two crosses* (like UK flag), pile on a blob of slip, score the pre-dampened landing spot (in no particular pattern), dampen it a touch more, then get to attaching. I don't mind if it slides a bit at first, for it tightens up considerably as the moisture dissipates into the surrounding (dryer) clay.
    For shallow angles, like the top portion of a mug handle's lower attachment, I roll a small coil (2-3 mm, if that), cut to length, wet it, set it aside. After all ends are attached, I'm brushing a bit of slip in there, placing the coil, then smooshing it in. The edge of a loop tool fits in there. A damp brush can help. I don't remember where I saw this, perhaps a Pinnell video clip.
    ...now I do the same on the top attachment as well.


    Why
    Variations on what we were shown in Wheel I class.
    There was talk of vinegar and "Magic Water" - I was curious; what is magic water**, how does it work, what are advantages & drawbacks?
    I was curious, but not enough to dig into it, for my attachments were much less a problem (at that time) than so many other things!
    Adding the tiny coil, well, the radius can be achieved by other means, shaping the end, for example (credit Simon Leach video clip).
     
    * The slip squeezes out along the score lines.
    Nah, but that was the idea, which is now habit.
    **Here's an article and recipe:
    Magic Water (ceramicartsnetwork.org)
     
  19. Like
    Hulk got a reaction from Pres in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    What
    Attachments (in my experience, err, limited experience), almost always one piece is damper than the other.
    The drier bit, I'll pick up half a drop of water with my finger and wet the attachment point - not enough to run, enough to impart a sheen that dissipates as the water is absorbed - add another half drop, as required (credit Ingleton potter Dick Unsworth's teapot process video).
    The wetter bit, I might dampen just enough to bring up a sheen, then score it in two crosses* (like UK flag), pile on a blob of slip, score the pre-dampened landing spot (in no particular pattern), dampen it a touch more, then get to attaching. I don't mind if it slides a bit at first, for it tightens up considerably as the moisture dissipates into the surrounding (dryer) clay.
    For shallow angles, like the top portion of a mug handle's lower attachment, I roll a small coil (2-3 mm, if that), cut to length, wet it, set it aside. After all ends are attached, I'm brushing a bit of slip in there, placing the coil, then smooshing it in. The edge of a loop tool fits in there. A damp brush can help. I don't remember where I saw this, perhaps a Pinnell video clip.
    ...now I do the same on the top attachment as well.


    Why
    Variations on what we were shown in Wheel I class.
    There was talk of vinegar and "Magic Water" - I was curious; what is magic water**, how does it work, what are advantages & drawbacks?
    I was curious, but not enough to dig into it, for my attachments were much less a problem (at that time) than so many other things!
    Adding the tiny coil, well, the radius can be achieved by other means, shaping the end, for example (credit Simon Leach video clip).
     
    * The slip squeezes out along the score lines.
    Nah, but that was the idea, which is now habit.
    **Here's an article and recipe:
    Magic Water (ceramicartsnetwork.org)
     
  20. Like
    Hulk reacted to Denice in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    If I just have  short seams I  use the clay body, water and lots of compression,  I am to lazy to mix up some magic water.   When I start on a large pot I will mix up some magic water,  I really never noticed any magic in slip with vinegar.    Denice
  21. Like
    Hulk reacted to Pres in QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?   
    I'm sure we have had this discussion a few years back, but good to return to it for those newbies out there. Over the years I have used all three, and found that I prefer the Magic Water. When teaching HS in the early years, I had used slip as that is what I learned to work with. If you you were diligent about your scoring, and your paddling/compressing the seams along with regular gap filling and smoothing you would have a good seam with no problems. However, being lax in any way could leave a seam that would split, or leave and ugly hole to be noticed even after glaze firing. Students took a long time to discover diligence. Vinegar was the addition that I started adding to my slip containers, as the mild acid did help to work the seams better. However, I came to believe that it was too easy for students to cover up a bad seam with slip of any sort than to get the seam right.  Along came Magic Water, and when I started using it myself, I knew that I had to start using it in the classroom. It did not change everything, but worked wonders with making seams and at the same time it was hard to hide a bad seam.
    QotW: Slip, Slip with vinegar, Magic Water: What is your choice, and why?
     
    best,
    Pres
  22. Like
    Hulk reacted to LeeU in QotW: Where and how do you store your clay?   
    My clay is indoors. It's a low production home hobby studio (I'm no longer doing retail in stores). It's tight at first, but I can fit two 25 lb sleeves in a 5 gal. painters bucket. Those sit on plant dollies. Works great! 
  23. Like
    Hulk reacted to Min in Strontium Crystal Magic Cool- Food Safe?   
    I prefer to use the term "durable" rather than food safe when talking about glazes. There isn't one agreed upon definition of what makes a glaze "food safe". In North America if a glaze does not contain lead or cadmium it can be labelled food safe. This is a very wide definition and adding something along the lines of what Mayco says "Finishedware producers bear responsibility for food safe testing their ware being sold into commerce." IMHO isn't good enough. Like Callie said Strontium Crystal Magic (SCM) is  fine on the outside of pots where your mouth or food won't be in contact with it.
    Re lithium and toxicity, just adding a little bit. Topic of lithium and toxicity has come up in many discussions in many forums etc over the years. My impression of the reading I've done is it might not be an issue for most people but for those on lithium therapy it can be, both in the process of mixing glazes and leaching glazes.  Poison is in the dosage scenario.
    With all due respect to Callie I found SCM quite rough, dry and unmelted. You could try it by itself on a test tile and see how you find it but it's a bit of a moot point because it isn't used by itself.  The overload of titanium is what makes the crystals/variegation when layered with other glazes. A good way to get interesting glaze reactions is to layer 2 or more dissimilar glazes, what one glaze lacks or has a surplus of reacts with the other glaze, this often results in interesting visual texture. SCM is loaded with fluxes to react with other glazes, that's part of the reason why it works.
    Re silica and glaze durability, having as much silica and alumina in a glaze is one of the ways to ensure a durable glaze.  For cone 6 having at least 2.5 molar of silica is a good starting place, if the glaze can dissolve more then it's a good idea to add it if you are looking for a durable glaze. If you look at the screenshot above in the bottom half of the image you can see the silica is 1.68 so at the bare minimum it is about 1/3 short of where it should be. Overloading a matte glaze can quite often turn it into a gloss glaze  and really oversupplying it can turn it back into a matte and crazed glaze so there are parameters within which to work. 
    Another aspect of silica that is often overlooked is the mesh size of the silica being used. When you mix glazes using a 325 mesh size silica more of the silica will likely be dissolved in the glaze than if you use 200 mesh. (not applicable for the SCM)
    One more thing is to look at the colouring oxides used. Don't use crazy amounts of colouring/transition oxides, use the least you can to still achieve the effect/colour you are after.
    There is a good article on toxicity that includes materials here if it helps.
  24. Like
    Hulk reacted to Callie Beller Diesel in Strontium Crystal Magic Cool- Food Safe?   
    Toxicity is a whole entire subject by itself. Mostly we have to start with definitions to help clarify. 
    Tl;dr, yes you can put this glaze on the outside of a pot and it will be fine. It’s not touching food. It melts fine at cone 6, it’s just a “soft” glaze.
    When a raw material is labelled toxic, that means it’s toxic in its current form. Once you put a material into a glaze with other materials and fire it, it becomes another material entirely, with different properties. If you’re using a commericallly mixed glaze that is labelled non-toxic, that means it’s not toxic in the unfired state. (It’s probably not toxic in the fired state either, but you’d have to test it to confirm, and manufacturers can’t say that it is for sure under all circumstances without legal problems. People do weird and unexpected things.)
    When we’re talking about glazes, most often the finished glaze is more safe than, say, raw lithium. So potters should be concerned about their own health and safety first, and the end user second. Materials like lithium can be handled safely with sensible studio hygiene practices, and can be beneficial in a lot of good glazes.
    When knowledgeable glaze chemists talk about food safety, we aren’t talking about whether a glaze will leach Bad Things (TM) into food. This is a very infrequent scenario outside of lead use, and lead hasn’t been used in most handmade pottery for decades now. But we are thinking about craftsmanship and durability. We’re asking questions like Does this glaze have flaws like crazing or pinholing, that can affect structural integrity or possibly harbour bacteria? Does this glaze scratch, or does it cutlery mark? Does it stain easily? Is it easy to clean? If those problems are solved, leaching is usually a non-issue. 
    Re the silica question: You need 3 types of components in the right proportions in a base glaze for durability: silica to form glass, alumina for strength and to make it not run too badly, and different metals that make silica and alumina melt at much lower temperatures than they do by themselves (fluxes). Without enough silica or alumina, or if those things are in the wrong proportions, the glaze may react to acids found in many drinks, bases like in dishwasher detergent, or may scratch or cutlery mark. SCM doesn’t supply enough silica for durability, but the strontium is also a problem.
    Within the flux category, there’s a bunch of stuff that’s a good idea to use in combination, because each material has beneficial and undesirable properties, and mixing them can bring out the best (or sometimes worst) of both worlds. For example, sodium is a strong flux, which is needed to bring down the melting temperature of silica and alumina, and is in most glazes. However, it tends to make glazes craze when by itself. But if you mix it with calcium (or barium or strontium or lithium and a few others), you can still get the melting, but less crazing.
    The calcium/magnesium/strontium etc group of fluxes also give you different colour responses, or can help create matte effects if the proportions are high enough. One of the drawbacks of using strontium or barium though is that neither is very high on the Moh hardness scale, so if you use too much of it, the resulting glaze can be prone to scratching, staining or other flaws. But it helps create that really cool matte surface because it promotes crystallization, so sometimes creative folks make trade offs. 
  25. Like
    Hulk reacted to Caroline E in Strontium Crystal Magic Cool- Food Safe?   
    @Callie Beller Diesel and @Min Thank you very much for your responses! I have some follow up questions. 
    Would the glaze be food safe if it was only applied on the outside? From what I can gather from your response, it is not food safe because it does not properly melt at ^6? I also wanted to ask you about the inclusion of lithium carbonate. I realize lithium carbonate is a toxic material. Does any ingredient labeled "toxic" mean that it can not be included in a food safe glaze? When any material is "toxic", is the concern in the powdered form or the fired form?
    Also, can you please expand on your mention of the glaze not including silica and what that does to the nature of the glaze? 
     
    Thank you very much 
     
    Caroline
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.