Callie Beller Diesel

If you’re wanting to mix a large master batch that then gets divided out, leave out the dry mixing entirely, but weigh the water. If you know how much water went into the batch you can divide it out evenly. If you keep to metric measurements, this will be easier, because 1 ml of water weighs 1 gram. It doesn’t work like that for all fluids, but it does for water. If you are used to using a measuring cup, check how accurate it is by filling it to a given measurement line and weighing it to make sure it’s close enough for your purposes. For instance, if you add 2500 g of water to your 5000g batch, the whole thing will weight 7500g, so a quantity of slip that weighs 1500g will contain 1000g of slip base. (Numbers made up off the top of my head for ease. You may have to play with your water additions to get your consistency right. Just record what you did.) From there, you can add your colourants to portions of your master batch. To mix thoroughly, you will need to use a stick blender that rotates really fast. If you use something slower like a jiffy mixer, you’ll have to let it mix a lot longer to get everything distributed properly. For some colourants that don’t break up easily, you may have to sieve the mix again.

@High Bridge Potterymostly they’re meant for things like antique/vintage housewares and detecting lead paint. They measure anything you can dissolve with the reagent supplied. So if there’s some lead there but it doesn’t dissolve, or if it’s below a certain amount, you could get a false negative from the home kits. They’re only meant for a quick yes/ no answer.

Hi and welcome to the forum! Sorry about the wait, we’re usually quicker than this. The number of pictures you uploaded is 1) absolutely marvellous, and shows all the good details we need, and 2) would have been too many for our server to handle. But in looking at them, I hate to say it, but the person who sold you that should have paid you $75 to haul it away. Cress Kilns is still in business, and still sell A series kilns, but only smaller sizes as testers. They haven’t sold A series as large as yours for a very long time. The serial number on yours says it was built in 1965. The electrics are very outdated, and may have never have had things like relays or switches replaced. Judging by the state of the rest of it, I’d be worried about internal corrosion. Replacing and upgrading the box is a project that people here have taken on with good success, and you mention you have the time and money for it. I wouldn’t have chosen it as a first project, but I fully respect anyone who loves to jump in with both feet. You’d learn a lot. BUT. Before you start, get a lead test on those bricks. Nothing fancy, just a swab from that website we all love and hate. Proceed accordingly.

Price check what they’d cost you from Euclid’s vs from Cress, including shipping and exchange. It might be less to order from Ontario. If you’re having trouble figuring out which elements you need and you’ve got a weird model either talk to Arturo at Cress (some of the others aren’t as knowledgeable) or call Euclids. Either one will get you sorted.

If it’s bone dry and you try to re-wet it, any water applied will work pretty rapidly to dissolve the clay. So surface texture will be altered somewhat. Readsorption may also cause small matrix cracks. If the piece is dear to you and you really feel like it can’t be re-made better, hollowing it out as Pres suggests is an option. The only thing I’d add to that would be to make sure you’re using a drill with low speed. Going too fast can cause structural issues from vibration. You will still have to leave the piece on the thick side to avoid damage, so you’ll have to go really, really slow on the bisque. Allow lots of time for the piece to absorb heat energy evenly. If the piece is truly bone dry and has been for months, explosions from water vapour expanding too rapidly aren’t a big possibility, but breakage due to uneven heating is.

While there are some commercial glazes that have lumps out of the bottle that will melt and smooth out, Stroke and Coat isn’t one of them. So, picking any visible bits off any unfired glazed pots is a delightfully simple solution to this problem! If the bottle has got a lot of dried stuff clinging to it, depending how bad it is you might want to clean it off or reincorporate the bits back into the bottle. You might have to sieve it, or spend some time breaking up the lumps with the back of a spoon. Stroke and Coat was designed to be used in teaching settings with children, or in paint your own ceramic places. Scenarios where you need something colourful and beginner proof. Most people aren’t used to working with how unintuitive glaze application is but they’ve worked with paint, and in these intro classes you need to get good results in a short timeframe. So the manufacturer adds dye for a what you see is what you get experience, and the glazes get glossy but don’t run when someone puts it on too thick. It was discovered pretty quickly that a lot of the colours could be successfully fired at higher temperatures without too much colour loss, so that’s why Mayco shows info on how to use some of them at cone 6. The people I now IRL that use stroke and coat on the regular use them at earthenware temperatures. My friends who own a paint your own ceramics place add an extra coat of clear glaze on top as insurance for customers, and the professional artist who uses them does the same to smooth out any appearance of brushstrokes. But I have to stress that’s at cone 06 (1000 C-ish). If you try this solution yourself at the temperatures you’re working at, put a waster slab under a test piece, and check the results for durability if you’re making kitchen ware for sale.

My dog Bruiser is a blanket baby, being possessed of little fur. (He’s a boston/pug cross). So he doesn’t like coming into the basement studio unless it’s high summer and too hot anywhere else. He’s not much of a studio assistant. This thing here, however, keeps trying to sleep on the reclaim bed that’s covered with a sheet, is deeply fascinated by both throwing and trimming, and keeps trying to go for a swim in my slip/glaze buckets. I present to you all my first-ever cat, Nippet. She would like to be deeply involved in all pottery processes, and has appointed herself official studio cat.

A drill that can stand up to grout mixing and a paint mixing bit if you’re going to do slurry reclaim.

The only way to know is to try it on one and see what happens. When you sand them down, look at the inside of the lumps to see what that tells you. Is it hollow? Does it look like a grog spec? See what you can see. In terms of picking a clay body, I can tell you what I’d do. That Witgert brochure is translated to English and Spanish it has a LOT of really handy information that I wish all suppliers gave out. I think there could be some candidates if you can get your hands on the right one. I’d suggest getting a hard copy of that sheet and lining it up properly though, lol! If you don’t go with a Witgert clay, look at the spec sheet from the manufacturer, not your supplier. Especially when translations are involved or the supplier is using their own product ID numbers that may differ from the maker, the manufacturer is probably more accurate. Check the top temperatures and the absorption rates of the earthenware clays. There are a few on the Witgert site that seem to be labelled as earthenware, but have absorption rates listed at <1% at 1200 C. Those are your candidates for cone 6 tableware. You could maybe fudge 2%, but make sure your glaze passes a hot/cold shock test if you don’t want coffee mugs with slow leaks. You may also be able to push a clay that’s close but not quite, but be sure to take precautions so you’re not wrecking kiln shelves when you test. Stroke and Coat is meant to be very user friendly for kids and other teaching situations. It goes on like paint and doesn’t move. The colour you’ve chosen is pretty easy to replicate in a lot of different glaze bases.

@k77 they could be related. According to the digitalfire article that I linked to in the post just above. grogged clay bodies can create more off-gassing issues because of the air pockets that the grog creates. This effect can be worsened if the glaze you’re using is not very fluid and don’t release gasses easily. That last describes Stroke and Coat very accurately. Stroke and Coat glazes are surprisingly not mobile for something that should be very over-fired at the temperatures you’re using. In North America, it’s best practice to match the glaze maturation point with the clay body you’re using because it prevents a LOT of problems. If you had been local to me, I’d have said to not use that clay/glaze combination at all. But we also have more stoneware clay bodies that are formulated to mature at 1200C/ cone 6. We notice here on the forum that suppliers in most other places tend to tell their customers to just use their high fire stoneware clays at medium range. It’s fine to do IF you are making sculpture and don’t have to worry about food grade durability, OR if you’re willing to do a lot of glaze troubleshooting to make it work. But it’s a lot less work to find a similar looking glaze that will mature at the same point as your clay, and fire both to that top point.

@Hulk K mentions in their first post that the bumps are raised. If it’s any consolation, I spent half an hour trying to figure out what might be causing pinholes before I re-read the original. I found the reference to the possibility of the clay body drawing flux from the low fire glaze on the digitalfire article on pinholing though. Which is why I thought it might be the grog.

If it’s your forming method, see if burnishing the grog back into your clay a bit with a silicone or other soft rib helps. Another easy test would be to see if the version of your clay without grog also causes these lumps. If it doesn’t, there’s your answer. Another thing I’d advise, whichever clay body you wind up with, is to do a porosity test to confirm your clay’s water absorption at your chosen firing temperature. In an ideal world, it should be under 1% for functional ware. If it’s less than that, you may find that things like coffee cups will weep.

Hi and welcome! Raised bumps are not pinholing, no. Unless the bumps are hollow, they’re not from off-gassing. The first thing that I’d check is if there’s anything that could have fallen into the pieces from the kiln shelves above them. If you’re using sand to place pieces on, or if there’s kiln wash dropping from above, that’s the first place I’d look. It took me a bit to decipher the spec sheet because of the brochure style layout, so I’ll transcribe here for the rest of the discussion. EDITED TO ADD: this clay body seems to be the one without grog, not the one with. This will affect water absorption and probably shrinkage. Assuming it’s plastic body #11 on page 6, then the specs are: Analysis: SiO2: 73.4 AlO2: 21.6 Ti.02: 1.2 Fe2O3: 1 CaO: 0.1 MgO2: 0.3 Na2O: 0.1 K2O: 2.3 LOI: 7.0 (If anyone wants mesh numbers, let me know, they’re on there, but I don’t think they’re necessary yet.) Plasticity: 24.4, Modulus of rupture 4.6, Dry Shrinkage 6.2 Fired Shrinkage: 1000C: 2.1 1100: 4.5 1200: 6.1 1300: 6.6 Water Absorbtion: 1000C: 11.8 1100: 7.2 1200: 2.8 1300: 0.6 If the bumps aren’t something that’s falling from above, the only other thing I can think of is a reaction between your clay that matures at 1300 C (cone 12) and your chosen glaze, which was only formulated for 991 C but happens to not run at all. Stroke and Coat is a weird animal. It could also be reacting with pieces of grog that are close to the surface on your pieces. Did you trim the surface of your plates or was there some grog on the surface that wasn’t burnished in?

Just a word on brushability: if you’re using gerstley borate, the mixture will brush quite easily the first day, or until it dries out. GB will keep your mix in suspension quite well, and is a preferable vehicle from an application standpoint. BUT I found small partially dried quantities can be difficult to reconstitute. Also, GB can affect some stains’ colour response. Worth doing some testing before you commit to a precious piece. If you’re using kaolin and frit, it’ll settle out a little more rapidly, but it’s easier to reconstitute the next day. If you’re mixing more than a few tablespoons at a time like I was, you might want to add a little epsom salt solution.

What context have you found this kaolin wash in? I think we need a bit more context I can’t think of a technique that would involve applying a wash made only of kaolin, unless someone was trying to create glaze “flaws” on sculptural work. The added dust is mostly going to make glazes applied over it crawl a bit. In some atmospheric firings like soda or wood, there are some bisque slip recipes that use different kaolins, but you need a thicker application than you’d get with a wash. The only other thing I can think of is that there are many kinds of kiln wash, some containing kaolin and some that don’t. If you’re going through someone’s old stash of materials, it could just be their shorthand to differentiate between 2 types.

It’s better to make the pots you can now than wait for ideal circumstances. It will extend your skills and your creativity. Also, build a business plan for yourself, not the kind you’d send to the bank. The starving artist trope is a steaming pile, and earning money at this is kinda fun! Make for the now, not posterity. History is unlikely to remember you, and that is a VERY freeing thought. You have ADHD. You need to find different working methods than the toxic work habits you learned in school if you don’t want to burn out. (That one’s personal.) You aren’t lazy for not wanting to make the work right now. You’re tired. Go rest and try again in a bit.

+1 for Min’s suggestion about making a support piece, or even building additional support feet into the design. I’d think it more unusual if a 14” long, 1/4” thick slab on feet didn’t warp.

Please, double check to see if your kiln is set to Celsius or Fahrenheit. You may not need to re-bisque at all. But if this message hits you too late, re-bisquing shouldn’t hurt anything. Depending on your clay, the extra heat work may or may not affect the porosity you’re used to, which can affect glaze application if you’re dipping, but I can’t see it being anything drastic. Pick one piece to test out and adjust your dipping times accordingly before you dunk the whole load.

How old is old? Some Cress kilns have a weird system where it’s an infinite switch that Dick describes, plus a thumbwheel that will turn the kiln up for you at varying rates.

If your supplier is willing to share when they took delivery of the stuff you bought, you might be able to figure out which one it is with this timeline.

You didn’t even get to cone 022. Yes, I would rebisque after you sort out your ventilation issues. Although, just because I deal with Celsius numbers a lot more, that 1045 number is suspicious to me. 1045 C is close to a cone 04 bisque. Double check which scale your kiln is set to before you do anything.

+1million for all clay not being created the same. I think the best thing anyone can do when they’re working in clay is to make their own observations about the materials they’re using. Supplier practices, material availability, recipes and user expectations do vary heavily from one location to another. The more specifics we get, the better help we can be. Links to product specs can be really helpful too.

If they’re not going to be in a freeze/thaw, then sealing them might not be necessary. The clay itself shouldn’t discolour, and most glazes won’t either. The exception being something like raku.

So, it sounds like you’re trying to figure out how to manage customer expectations, and figure out where your policies are in relation to your booth neighbours. If other vendors are setting the expectation that customers get a discount on venmo transactions, that seems odd, because it’s all electronically recorded even with the personal account option. Most farmers I work with deal with million dollar operations, so they’re subject to RevCan scrutiny and I can’t see it being that different in the US. So it’s probably worth talking some shop with your booth neighbours. Are they in fact giving discounts, or is the sales tax buried in their sticker price? As long as it’s documented and recorded on the receipt properly, that could be a viable possibility, or a workaround for yourself. As long as your area doesn’t have a rule against it, that is. If the other vendors aren’t setting an example of cash or Venmo discounts and someone gives you side eye about taxes, this usually means that you’ve got some customer audacity on your hands, and there’s a lot of ways this can be dealt with. If anyone ever needs help with scripting, I’m pretty good at it, and I can walk folks through the principles of how to do it yourself. You can set boundaries and hold them firmly without being rude or harsh. Personally, I don’t discount the sales tax percent for cash sales. I don’t offer my customers explanations, because that leaves wiggle room for arguments I’m not interested in having. “It’s not my policy to do that,” or “RevCan takes a dim view of that,” is the most they usually get. Your customers aren’t entitled to your financial practices.

So much this! While I do advocate for social media as a valid business tool, it’s not one that I think everyone needs to pick up. If ANYTHING doesn’t suit one’s constitution or life or business model, it makes no sense to use it. It’s like a Giffen grip: some people love it, some people hate it. Both are valid. Social is one way of building an audience, but not the only way. Circumstances and nuance need to be considered.