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Min

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Everything posted by Min

  1. It does look good for work that doesn't contain anything that could be harmful, but not for over underglazes. From their FAQ page "No, Liquid Quartz cannot make your underfired or toxic glazes food safe." https://madeofaustralia.com/data/documents/Liquid-Quartz-General-Information-Sheet-V042016.pdf https://madeofaustralia.com/faq/ Welcome to the forum and thanks for letting us know about it
  2. I do sell "seconds" but you have to really look hard to see why they are seconds. I always try and point out why something is a second to a potential customer and 99 out of a 100 times the customer will say "Well that's what gives it character". I smile and think to myself no, you just are pleased to be paying 1/2 price for the pot.
  3. A suggestion re handles, I see your mug on the left has gone oval, if you are okay with that then no worries, if you want mugs to stay round then after attaching the handle true up the rim again. You can do this by pressing in a tapered cup, like the Solo red beer cups, press it in the mug until the rim is pressed back into round then while holding the base of the mug pull the cup straight up and out. Can also make a bisque cone shape to do the same thing. If you are limited in how many pieces you can fire I would practice making a couple dozen handles to start then attach them to some of your already glazed and fired mug rejects. Stick 3 or 4 on each practice mug, go through all the handles then line them up to see what looks better. Take the best handle forms then put 3 or 4 on a practice mug, glaze fire and see which handle works and looks the best.
  4. Vacuum pump is just in front of the screens on mine. Clay is like 1/4" spaghetti after coming through the screens then it's de-aired (for machines with vacuum) and compressed in the end two sections.
  5. 2 for Bailey. I've got this one. Can't say enough good things about the Bailey mixer / pugger and Bailey's customer service.
  6. What a lovely wedding present! Such a nice thing to make for them, hope they fill it with love, wishes and dreams.
  7. Getting the slip on the pot as soon as possible while the pots are still leather hard, or softer if possible, is the safest way to go. If the pots are too dry the slip will likely flake off or develop cracks, or the pot can crack, also the slip won’t bond with the pot as well. On the other hand you don’t want the pots so wet that they sag or soften too much when the slip is applied. Dipping a pot in slip requires really careful timing or the pot will split from all the added moisture. There are slip recipes that are formulated to go on dry greenware or bisque if thats what Becs wants to do. Yes, colouring slips with oxides / carbonates or stains is something you can do. Ball park rough amount for stains would be 10%, then adjust from there, 3 -5% copper carbonate for copper greens, 0.5 to 2% cobalt carb for cobalt blues (if you use cobalt oxide you would use about 1/3 less, cobalt oxide speckles), 5 - 20% red iron oxide for browns. The clay body and the slip need to have similar shrinkage or during drying and firing it may peel or flake off. If you use a light clay body you can use it for making into coloured slips since it will fit the clay body. Yes, cone 6 clay with slips will work too. Your lowfire clays might work as slip or might not. Have to try and see. If they don’t work then a slip from a cone 6 clay will work or a ^10 porcelain or you can mix up a slip recipe. Sieve your slip, mix it up to about heavy cream consistency and try some tests brushing on 1, 2 and 3 coats. I’ld start with some test pots, brush, dip or trail your terracotta slip onto leather hard and see what happens. Check for cracking/flaking while it dries, bisque and glaze fire and check for fit.
  8. Min

    Help!!!

    It will get washed off if it wasn't bisqued on, like Pres said, some left in the recesses of the works might be nice. I'ld wash them off, let them dry out and have the students redo the decorative colour glazing. It can be hard to tell the colour of glazes by the raw glaze colour, if you put some food colouring in your clear glaze you will be able to identify it in future by it's different colour. Welcome to the forum
  9. Where do you start when choosing glazes? Simple answer would be they develop over time or they are the ones that sell but looking deeper than that… Do you use the shotgun approach and mix up test glazes from books or the internet that you like the looks of? Do you take a base glaze that you like and try it with different colourants and opacifiers just to see what you get? Do you have an idea of a glaze colour and surface that you want to make and then build a glaze from scratch or alter an existing glaze? Line blend of glazes, triaxials, Currie grids, overlap existing glazes? Try out different firing schedules to see what happens to the glazes? If you use commercial glazes what do you look for, do you change them in any way? I’m always mixing up glaze tests, lately I’ve been working on a more earthy glaze colour so it had me pondering this question, would be interesting to hear how you choose your palette.
  10. Min

    "dangerous" glaze ingredients

    I've used Brandywine, cost is approx $30- to test for one material plus the cost of shipping a small test piece there. You get results by email in about a week. Directions for making and sending in a test piece here. Agree with Mea, find out one way or the other. I'm not sure that Alfred Analytical is still around.
  11. Min

    Underglaze versus glaze?

    Duncan sells clear sealers, both matte and gloss, that would help protect it. Some underglazes flux more than others and create a better bond with the clay than others. (If you do try the spray I would try it on a test piece first) If you can't get Duncan or a similar product where you live I would try a non yellowing acrylic spray from a hardware store.
  12. Min

    No Swiping

    I heard back from Square re Apple and other contactless payments. Seems they are covered with Squares chargeback coverage unlike swiped chip cards. "The Square contactless and chip card reader accepts chip cards (EMV) as well as contactless payments (NFC). Contactless is a term used to describe the act of paying without touching anything. NFC (near field communication) is a technology that allows for contactless payments. Apple Pay and Android Pay are examples of contactless payment platforms. NFC uses a specific radio frequency so devices, like smartphones, can wirelessly communicate at close range to do things like process payments. This means these payments are very secure, much like chip cards, and do not subject you to an EMV liability shift related dispute."
  13. Min

    Underglaze versus glaze?

    Underglazes can be left unglazed to create a matt look similar to engobes or coloured slip but the surface won’t be as smooth as a glazed surface. I’ve had just a few Spectrum underglazes flux to the point of becoming glossy at cone 04 but mostly they stay matte at that cone. Using a clear glaze makes the colour pop. Underglazes allow you to blend and layer colours in a way that would be very difficult to do with glazes. Some lovely examples by Terri Kern here. edit: for functional pots underglazes should have a food safe covering glaze
  14. I would look at few possibilities, first off the design of the bowls, I would look at how much overhang from the foot you have and the design of the rim. If your aesthetic allows a change in direction with the rim, adding a flared outward small rim flange would help stabilize the rim, if not then beefing up the rim helps. Any small warping that happens during drying the bowls will be magnified during glaze firing so even wall thickness and even drying need to be looked at to prevent warping while drying, as does how you remove the bowls from the batts. Do you put another batt on top of the rim and flip the bowl over while sandwiched between the 2 batts? Also, when firing is the kiln shelf smooth, no crusty bits of wash for the foot to snag? I would use cones to ensure you are not overfifing which can cause warping especially if you use porcelain or porcelain like clay as it gets soft and prone to slumping. You mentioned that this is a new problem, makes me think something has changed in your process, drying speed, humidity, design, something has changed.
  15. Min

    No Swiping

    From an email from Square regarding Square Tap-and-Pay: "If you swipe a chip credit card and the cardholder disputes the payment with their bank as fraudulent, the bank will immediately rule in the cardholder’s favor and the disputed funds will be automatically debited from your account. To avoid this situation altogether, you need to insert chip credit cards into a chip reader, like the Square Reader for contactless and chip." I've emailed Square asking if the same policy applies to Apple Pay and other NFC-enabled smartphones and watches but haven't heard back from them yet, anybody know what the policy on this is? I've used the tap feature for lots of transactions before receiving this email but will be inserting the chip cards now. I don't know if this only applies in Canada.
  16. Min

    Cracks In Bisqued Pieces

    @jknake, as well as pictures would you post your firing schedule? Welcome to the forum
  17. Min

    Porcelain Clay Bodies

    Adding to what Chris said, cone 10 B-Mix is very forgiving and easy to throw. (I find it's a much nicer clay to work with than the cone 5 B-Mix) It's not white but it's a light body, very smooth, generates a fair bit of slip while throwing and you can throw fairly tall with it. Could add a layer of slip to it like LT suggested if it's not white enough.
  18. Last pot on the bench today, carved vase.
  19. Min

    First glaze tests down the drain

    Yappy, if you put cone packs inline with the spyholes you can monitor the cones towards the end of the firing. Wear glasses meant to be used for looking into a kiln to protect your eyes from both UV and IR radiation, they will be green #3 lenses. Shut it down before it overfires and do the tc or cone offset if necessary.
  20. @Gokul, have you run through some clay testing procedures? My first thought is you are experiencing water splitting, the split in the wet pot on the wheel in your first photo appears to show this. Simple to test for water splitting, about half way down this link there is an explanation of how to go about this. Have you done a sieve analysis?
  21. Any chance the darvan has expired? (approx two year shelf life)
  22. Min

    is this glaze food safe?

    Lots of debate on this forum as to whether or not copper leaching is an issue or not. Here is one of the discussions that is worth reading. To make a stable glaze there are "limits" for the necessary amounts of silica and alumina (and other oxides) for glazes. If you fall far below the limits for silica and alumina the other oxides in your glaze are more prone to leaching out of the glaze. Have a look at column one in the chart below, it is the formula for your glaze (without the copper), now have a look at the last column, it is the "target limits" from Green & Cooper for a cone 10 glaze.
  23. Min

    Old Gold Albany Flakes off

    3110 instead of Neph Sy, I'ld run tests with both. The 3110 has a higher COE (coefficient of expansion or sometimes called coefficient of thermal expansion) so it will raise the COE of the glaze more than Neph Sy will. One might look better than the other or the 3110 might actually be too high a COE and cause crazing, don't know until you run some tests. I don't know how much you have done this type of tinkering before so apologies if you already know this but to do this testing quickly and to get as much info as you can from it this is how I would suggest doing your tests: Mix up glaze 1 as 78 Albany plus 5 lithium carb plus 12 zirco plus 5 Neph Sy. Dip a test tile and double dip the top of it. To the same container of glaze 1 add another 5 Neph Sy and dip a second test tile, double dip the top. Mix up glaze 2 as 78 Albany plus 5 lithium carb plus 12 zirco plus 5 ferro 3110. Dip a test tile, double dip the top. To the same container of glaze add 5 ferro 3110 and dip a second tile, double dip the top. Since you already have those 2 glazes mixed up I would then take equal parts of both of them, just by volume is fine, mix them together and try this third new glaze. Take your best result and before using it on real pots make a very thin walled cylinder, it can be just a thin slab or thrown, doesn't matter but make it thin then glaze the inside plus the rim very thickly with glaze. Get it on as thick as you can without it crawling (cracks while drying will be crawling when fired) and fire it. Freeze it then pour boiling water into it and see what happens.
  24. Min

    Old Gold Albany Flakes off

    If you have frit 3110 I would try that also, reduce the lithium carbonate to at least 5 and adding up to 10 of the 3110. Apply the glaze thickly on the rim of the test tiles.
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