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  1. I’m confident you’ll find a solution very soon. When I started most manufacturers where in the process of reformulating leaded glazes (which up to that point many where still considered and labeled as food safe) to make them lead-free and for a while the new recipes were not very good for brushing. These days there are many good options.
  2. It sounds to me like the glaze might need more binding (gum) material… https://digitalfire.com/4sight/troubleshooting/ceramic_troubleshooting_powdering_cracking_and_settling_glazes.html ‘’Add CMC gum to powdering glazes. In industry gums are standard practice, companies know how to deal with their side effects. But potters should be aware of the impact of using a gum. Like bentonite, it needs to be added during dry mixing. Gum is glue, it is very sticky, it hardens. Using gum is a crow-bar approach, a way of 'gluing' a glaze on the ware. Strangely gum also helps suspend. Gum burns away so it has no effect on glaze chemistry (although the decomposition can produce glaze faults like blistering and pinholing). One serious problem: gummed glazes dry slower and drip-drip-drip after glaze slurry pull-out. This can be compensated in most industrial processes, but can be a total pain in pottery. Experiment with the amount, try 0.5% to start. Add it as a gum solution to the water (deducting the amount of solution need from the water requirement). Commercial paint-on glazes often contain so much gum that the recipe contains zero-water (only gum solution and the dry materials).’’ https://digitalfire.com/4sight/material/cmc_gum_228.html Personally I avoid using powdery glazes, adding a gum to a powdery glaze is a solution I use only when there’s no other option. Usually I just mix it with another glaze to make it brush well and then fix the recipe or buy/mix a different glaze. I’m inclined to think that the problem is the glaze and or the application. Not noticing a pattern in the firing also points to the glaze being the problem. If your friend’s kiln is bigger it might have a different ramping curve, but if she’s not doing reduction probably the difference shouldn’t be that big. If you make a tile about 5 inches wide and progressively apply the glaze thicker as you move to the right (one thin coat on the far left, then two coats, then 3, etc.. then scratch with your nail to judge the thickness) you might be able to tell thickness needed and if the glazes is bubbling due to it being layered too thick. The bubbling in photo seems to look like what I’ve usually seen with powdery glazes applied unevenly or needs remixing or an opaque glaze applied too thick. https://digitalfire.com/4sight/troubleshooting/ceramic_troubleshooting_glaze_pinholes_pitting.html My experience with speedball glazes will not translate to your clay and firing methods. I single fire terracotta (red) clay to cone 04-02 in 5.5-8 hours, no hold or slow cooling. It makes me guess that if the thermal expansion of the clay isn’t drastically different from the earthenware average, many glazes are not that finicky and should work great for you as well… My suggestion is to use whatever works best right out of the gate to avoid getting too frustrated. As you get more experience you’ll be able to make most glazes work and know which to avoid altogether. Maybe try whatever you can readily source at a good price. If you are a visual learner, check with local friends, sit down with them and let them show and explain how they go about the process. Or check youtube… https://www.youtube.com/watch?v=_85QWDsIa80 Many 'ifs' and guesses... hope it still helps you in the search for a viable solution...
  3. You’re welcome. I also had a hard time figuring low fire clay/glazes when I started many years ago due to the lack of information available then on web. Is your friend using the same clay? Have you checked if she/he is applying the glaze in the same manner? Would he/she be willing to fire a small glazed bowl of yours and vice-versa? There are several things that can be causing the problem, but if you say that the glaze looks like paste then most likely the problems is the glazes need a suspender/binder and maybe remixing. Does the glaze after a few days of being unused separates with water on top and a hard mass at the bottom? You could try mixing a cmc or xantham gum solution. Cmc is an organic substance and spoils overtime, so mix small amounts (5mg to 1 pint of water is what I usually mix because I don’t use it often). Pour the glaze amount you are going to use in a bowl and add small amounts (few drops at a time) of the cmc solution until it brushed the way you want it. Xantham can be found in bakery shops and online store like Amazon, if your local pottery supplier doesn’t sell it… Big commercial glaze manufacturers use fungicide and the glazes keep they brush-ability better over time. You could search the archive for Neil Estrick’s posts. I think he was the one that explain this to me some years ago… http://community.ceramicartsdaily.org/topic/5582-suspendersbinders-in-speedball-glazes/ Maybe buying one or two 4oz Duncan or Mayco glazes can help you figure out if that is the problem. Most likely you need more practice brushing the glazes and maybe a new glaze source, but possible cause for the pinholes: -The glaze application is too thick - The glaze wasn’t properly mixed or the suspender/binders clumped up. -The bisque had dust -The glaze didn’t fully mature or didn’t had time to heal. Your thermocouple might be slightly off, you could try firing cone 05. - The bisque wasn’t porous enough or to porous and that can make even application more difficult. If you notice the bubbles in the unfired glaze coat, rubbing the bubbles with the finger can solve the problem. You could also try adding some clear glaze to make the glaze more fluid. At one point I used to add 1:5 of clear glaze to Duncan’s downright white glaze to avoid pinholes. Brushing the first coat up and down and the second side to side can help too. To ability to judge thickness comes from experience, making many small slabs or shallow bowls and systematically try all the brushing options could speed up the process of finding out a solution. I slow ramp up because I single fire, don’t hold at top temp or ramp down my firings, just fire to a cone or two hotter (cone 04-02). That is a personal choice since I don’t have time to baby the kilns. I also apply most glazes using a single thick coat of slightly watered down glaze. Focus on the small successes and keep trying until you sort it out…
  4. Not an easy task and most probably not very durable. :( at low firing temperature even many glossy glazes are not durable... Also, at low temperature my experiments over the years have yield whitish/milky transparent rather than clear. You could search for a recipe containing barium (either carbonate or frits like the P-626) or maybe lithium, but I wouldn't use it for functional work. You could try locating this book in a nearby library which has tons of recipes: The Potter's Complete Book of Clay and Glazes: A Comprehensive Guide to Formulating, Mixing, Applying, and Firing Clay Bodies and Glazes Hardcover – May 1, 1991 by James Chappell You'll probably be better off getting a Duncan or similar pre-made glaze if it's going to be used in functional ware... You could try using a watered down shinny clear thin coat and it might give sating enough result specially if there’s an engobe or slip with enough flux underneath it. This standard clear recipe is semi-glossy but almost sating when fired lower than cone 04, but like most glazes with high percentages of boron it can produced a lot of tiny bubbles, not exactly clear. Ron Meyers/Daniel Rhodes cone 04 clear 80% frit f3124 10% Silica 10% Kaolin (EPK) 2% Bentonite Here's one I just found doing a google search... but not clear/clear and it needs a special firing program. I might try it, too... As noted in the comment section: My satin clear glaze uses some weak forms of iron to give it a tone that mutes the colors a little. It softens them a bit. And the glaze isn’t truly ‘clear’. It’s translucent actually. The thing that makes it satin is the crystaline growth. Crystals are opaque. So it’s quite an interesting balance of things that allows the color to come through without making the glaze shiny. A friend who is a ceramic engineer helped me to formulate it. And I fire to cone 1, not 04.' http://www.lisanaples.com/ceramics/recipes/naples-wagner-satin-clear-cone-04/ Naples-Wagner Satin Clear (cone 04) The Wollastonite is your matting agent here so adjust accordingly Frit 3134: 40 Lithium Carb: 7 Wollastonite: 25 OM4: 25 Yellow Ochre: .5 Black Iron Ox: .5 Notes: The Naples-Wagner Satin Clear Glaze should be used at a density of 1.44. Email me if you’d like to purchase a density cup. As a service to the ceramics community, I import the same kind that I use through my ceramic engineer friend, Karla Wagner from an Italian engineering firm. Price bound to change over time (but to give you a ballpark, they were $200 ea. in 2013). For a quote, contact me. In order to get as much satin as possible out of this glaze, it’s best to fire your kiln DOWN. Crystals grow on the cooling cycle between 1900-1400 degrees. I use a final ramp in my firing program that allows for 100 degrees/hour from 1900-1400.
  5. Maybe just get a few small jars to try and see what works for you... I mix most of my glazes, but do use some commercial glazes, among them Duncan, Mayco and Speedball. I have used Amaco glazes too. Speedball glazes are the best ones for brushing, but the color options are very limited and many of them are rather ugly when used on red clay or just plain ugly in any type of clay. I have tried to find which gum/adhesive/suspender they use (smell like a gluestick I used in grade school of which I can’t remember the name ) but no luck so far… They aren’t vibrant in color, probably not what you are looking for. I like the white, black, blue and Purple glazes. Other than that is not easy to generalize the brush-ability of a brand, since some glazes of the same brand might be good for brushing while other might not. Amaco’s non-toxic F line I found really hard to brush, but I’m not sure if the problem was that they were old and bacteria had decomposed the gum or if they are always like that. The Art series was nicer to use. The same thing with Duncan and Mayco, some colors are better than others. Really opaque glazes tend to be more troublesome than the semitransparent ones, but the opaque glazes are the ones that usually achieve even solid colors and stay put when fired. Glazes with crystals are a really fun to use but tricky to apply and give quirky results. It took me a long time to get the process right, and what works for somebody might not work for another. Some of the solutions that either work for me or for people I know: -Using a watered down first coat, adding a small amount of water the glaze or wetting the tip of the brush in water before dipping it in the glaze. -Adding some kind of gum/suspender like CMC/Xantham Gum… but some people add other stuff like bentonite solution/ liquid dish soap/ Glycerin/ Ironing Starch… -Fire a cone or two higher The brush selection makes a big difference too… I like using really soft hair brushes. Some people prefer fan brushes. I think the key is and being able to tell by sight the coat thickness and get an even coat that is not too thin so the color is even and not too thick to avoid pinholes/shivering etc... Regarding what is food safe and what is not, I recommend that you read up on the subject and draw your own conclusions. There are many chemicals that are not regulated that I rather not use. Also, a glaze that is labeled as non-toxic might not necessarily be durable. Vinegar on a glazed bowl will quickly show you that after a couple of days… That’s why I mix my liner glaze. What is microwave and dishwasher safe is another matter you might want to research…
  6. Sometimes I've noticed the recycled clay being short, I use it for small pots... The local supplier doesn't sell the dry clay mix. Would the short clay cause cracking problems with small 4"x 4" terracota slabs? Thanks
  7. Cone 03 and cone 3, not the same thing... But if you actually fire cone 03, the link below has several recipes for slips that can be used on greenware and bisque. www.priscillahollingsworth.com/uploads/4/9/8/3/4983085/lowfire_glaze_list.pdf Btw, underglazes are usually dry (not glossy), is that what you are looking for? Regards
  8. Yes, zircopax can be used to make white glazes. The problem might be it giving a different kind of white, if the white stain sold where you live uses Titanium or Tin Oxide as an opacifier instead of zirconium silicate. Some people feel the Zirconium white is too bright/harsh, you can use half Zircopax, half Tin oxide and or add small amounts of Titanium Oxide or light rutile to tone it down. I think you are firing to cone 5? Not sure how much you’d need to add, because I use cone 03 terracotta clay. Some recipes call for up to 20% of zircopax. I use about 12-15% (but usually 10% is enough) when looking for a solid white and since my glazes are balanced never get pinholes. But according this old link it seems that my experience holds true at cone 5/6. http://www.potters.org/subject21453.htm Pinholes could be caused by different things (zircopax has never given me much trouble). The Recipe, how you mix it, how you bisque and what type of clay can also factor in: https://digitalfire.com/4sight/glossary/glossary_pinholing.html https://digitalfire.com/4sight/troubleshooting/ceramic_troubleshooting_glaze_pinholes_pitting.html Peeling is cause by the clay and glaze having different expansion % . https://digitalfire.com/4sight/education/understanding_thermal_expansion_in_ceramic_glazes_198.html https://digitalfire.com/4sight/troubleshooting/ceramic_troubleshooting_glaze_crazing.html https://digitalfire.com/4sight/education/adjusting_glaze_expansion_by_calculation_to_solve_shivering_199.html That website also has recipes… You could try doing a 3 part line blend. Adding Zircopax starting with 5% up to 10%, and then add 2 to 3% of frit and/or subtracting 2 to 3% kaolin at a time if you get pinholes. Probably bentonite is not needed, because the recipe you listed is very high in clay content … you could try adding 1% if needed… https://digitalfire.com/4sight/material/bentonite_106.html Good Luck!
  9. Hi, I’m ordering zirconium silicate. Through the years the names and manufacturers have changed. It’s been some years since I last placed my last order and would like some help. I used to buy plain Zircopax, the Super Pax, then Ultrox 500 and last time Zircopax Plus. Yesterday, when asked, the store told me that both Zircopax and Superpax where manufactured by Endeka and that they come in the the same bag labeled Zircopax Plus but one has a sticker that says Zircopax and the othe Super Pax. A search in the web revealed that Endeka was acquired by Ferro last year, but no news about what’s going to happen with Zircopax. Digital Fires article on Ultrox mentions a new manufacturer of Ultrox, but don’t know how long it’s been since it was last updated. Though, I’ve been able to use them all with minor adjustments. I would rather order the one that is more likely to be available for the foreseeable future… Does anyone have up to date information that would help me decide which Zirconium Silicate/supplier to use? Thanks
  10. Thanks, that's what I thought. When I get a chance l'll check for a loose connection just in case.
  11. Thanks Neil, the top and bottom elements glow and the two middle ones glow less but seem to be on as well...
  12. Not when I plug it in, but when I turn on the switch. Late last night and again just now I tried again and it worked correctly. Then again I've just kept it on for less than an hour. Don't know if unplugging the kiln when not in use makes any difference.
  13. Thanks for all the replies… No the kiln can’t be manually controlled… no l/m/h settings… The way I found to work around the single segment ramping is to programs one segment for the first 500 degrees and the enter another for the rest of the firing. Pretty easy and straight forward, like Min suggested, but the kiln doesn’t have a fast setting so you have to manually enter the number. The problem I have now is that the kiln is acting up again. When I turn it on it starts ramping the heat, not responding to the controller and making a buzzing sound that gets louder and louder until scared I throw the switch off. The turning it on while pressing the select button trick is not working any longer… Any ventures to guess what might be causing this? Anyone has any experience converting a digital kiln to a switch/sitter or exchanging the controller for a different one? Or know of any links with info on how to go about doing it?
  14. Hi, a friend of mine gave me an Evenheat kiln with a Perfect Fire digital controller. It hasn’t being used in many years. When I turned it on, the kiln started heating like it was on high and it wouldn’t respond to anything I pressed on the controller’s interface. I called Evenheat and was told by the person who answers the phone (not sure if a tech) that it was the relays. Replacing the controller, if also damaged, with a new one would cost $450+/- plus the cost of shipping the panel. When I opened the kiln the relays didn’t look burned out. I looked around the web and found this post: http://www.potters.org/subject44399.htm . The trick bellow seemed to get the controller working again. >>>Hold down the "SELECT" key, while turning the power switch on. The controller enters the programming mode, indicated by the top lamp flashing. <<<< I have a few questions and will also be thankful for any other information on how to use/repair the kiln. This controller doesn’t offer a multi segment ramping. Does anybody know how get around this limitation? I don’t need anything fancy; just want to be able to slow down the first 2 or 3 hours of the firing and then rocket fire the rest of the way. Also how do I check/ calibrate the thermocouple? I still plan on using a small cone on the shelf. Are there any other alternatives (specially cheaper ones) to sending the panel to the manufacturer? I have other kilns, so I don’t really need it. Still, it’ll be cool if I can make it work without spending much, because its 3.3cf is perfect for experimenting… Thanks,
  15. HI, some points to consider… -The bended cone you are seeing doesn’t necessarily mean the rest of the kiln reached the same temperature. I’m not sure what you mean when you say until I see my cone start to slump. You could check Orton’s website if you’d like to see a diagram of what a properly bended cone looks like. Maybe your kiln is not reaching cone 06. - Is the firing time equal in both kilns? - If the kiln you have at home is smaller or less insulated, you might need to fire a cone higher, do a soak at max temp or slow cool the kiln so the glaze gets to melt fully. Some glazes start melting way before the cone drops, others melt fast near the end of the firing, and others bubble and need time to heal. I never fire glazes to cone 06 anymore. I fire with a 04 or 03 cone in the sitter and Speedball glazes rarely give me any troubles. Speedball glazes I think use a different kind of gum and brush differently. I made test tiles big enough so I could brush the whole tile with one coat, ¾ with two coats, ½ with three coats, and ¼ with 4 coats to see the difference in terms of opacity and glossiness…
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