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GiselleNo5

Weird Liquefied Slip ....

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I use a lot of slip trailing on my work. I had originally been using casting slip for my slip trailing because it was easier and at the time I had no place to mix slip, but now that I've made my own I'm never going back. 

A few months back I made up a big half gallon jar of B-Mix slip that I use both for slip trailing and for painting inside cups and bowls of dark clay so I can do a bright color inside. I like it really thick, like sour cream, just thinned out enough that it will come out of the slip trailer, but when it's thick like that, it holds its shape really nicely and gives a beautifully defined line, which I love. It was mostly just B-Mix and water, but I used a little vinegar so it wouldn't get stinky and it had maybe 8 oz of white stoneware casting slip too, just because I thought it would help my slip set up nicely. It worked out really well on every single clay I'm using right now. Over the next few months I used all but the last 1 1/2" of slip in the bottom of the jar, then I went a few weeks without using any.

 

On Saturday I went to slip trail some things and it had turned liquid, like heavy cream, and it looked, felt, and behaved like pure casting slip and was very runny. It did not hold its shape when used at all. I didn't add anything since the last time I'd used it. I wouldn't have been surprised if it was thicker or dried out but this was just weird. 

 

The only thing I can think of is that perhaps the vinegar had something to do with it? Or is it possible that the casting slip had settled to the bottom of the jar somehow and that was mostly what was left? 

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The vinegar you added made your slip flocculate, and now it has deflocculated again.

 

http://digitalfire.com/4sight/glossary/glossary_flocculate_flocculation_flocculant.html

 

This isn't exactly what your doing but it pertains to getting slip back to the state it should be.

 

 

 

There is also a lot of topics on here about adding epsom salt and water to things. Look that up for more information. 

 

I think the normal recipe is 1 cup of water to two table spoons of epsom salt.

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Man I am always getting these two confused. So vinegar suspends and gels AKA flocculates along with epsom salts? I remembered watching Tony's video about gelling glaze with vinegar but still couldn't remember properly xD

 

 

My second time watching this, and this time I'm coveting the drill press mixer! Just what I needed - and so quiet!

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Man I am always getting these two confused. So vinegar suspends and gels AKA flocculates along with epsom salts? I remembered watching Tony's video about gelling glaze with vinegar but still couldn't remember properly xD

 

 

My second time watching this, and this time I'm coveting the drill press mixer! Just what I needed - and so quiet!

 

 

Best part is it will never scrap the darn bucket and leave plastic in the glaze that you have to sieve out. I do that nearly everytime I use my drill mixer lol. I really need to get a better one that doesn't do that, but I just don't mix large buckets enough anymore. Use my hand blender thing from my wifes kitchen, muahaha.

Rae Reich and Karen B like this

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The purpose of the video above really has little to do with suspension. It's all about the gelling, which in my opinion isn't at all necessary for everyone. It's just one way of doing it. He said that the glaze has 20% kaolin in it, which would keep the glaze suspended quite well without adding anything to it, as long as he didn't add so much water to it. Add enough water to any glaze and it will settle. While the gelling does prevent drips, the down side of the method he's using is that he's now got a glaze with a high water content, which means it will dry very slowly. For someone like me who makes thin pots with up to 4 layers of glaze, that kind of drying time wouldn't work. If you watch closely, his mug stays shiny and wet the whole time he's talking after he dipped it, and he only dipped the outside.

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I would think the vinegar. Are you sure it wasn't too thick the last time you used it and you added some extra that after the few weeks has thinned more?

 

I am 100% positive I had not added anything to it. In fact, I kept expecting to need to add water etc. but the slip was absolutely perfect for months of use till it went thoroughly bad at the end! 

 

So basically the vinegar lost it's "oomph" (do you like my use of technical terms?) and the slip got runny again. That's fine, next time I'll just add some more clay from my scrap bucket and a little more vinegar. I was just afraid I had created some kind of strange chemical mess somehow since I hadn't touched the slip in weeks. 

 

Side note: The vinegar makes a definite difference when I add it to the slip. It gels up like whipped cream almost and it holds its shape just beautifully, although it does shrink down later. The first time, I was just adding it to keep bacteria down, and it kind of floofed up like marshmallow cream. I was so surprised. The jar was already pretty full and when I added the vinegar it suddenly got really thick and poofy and started this slow lava flow out the top of the jar that just seemed to keep going and going and going. LOL SURPRISE! Your gallon of slip is now 1.5 gallons and most of it is on your apron! You're welcome! 

 

 

clay lover, Karen B and Priscilla like this

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Neil you are totally correct. I think that video was aimed a previous article he had put on digital fire which references bisqueing pots as high as cone 03-02. To burn out impurities and help with surface defects. 

 

http://digitalfire.com/4sight/glossary/glossary_bisque_bisquit_firing.html

 

He has an image in that article related to bisqueing to cone 02. 

 

 

 

The buff stoneware mug on the right was bisque fired at cone 02, the one on the left at cone 06. The cone 02 mug was immersed in the clear glaze for 1 second and allowed to dry. The other was glazed on the inside first, allowed to dry, then glazed on the outside with a 1 second dip. Of course, the cone 02 one took longer to dry. In spite of this, the glaze is thicker and more even on the one bisque fired to cone 02. How is the possible? The secret is the thixotropy of the glaze. When that is right, a one second dip will give the same thickness and evenness whether dry or bisque, 06 or 02. Why bisque fire to cone 02? To get a glazed surface free of pinholes on some stoneware clays.

 

gixxapefyx.jpg

 

The video I posted about slips is much more related to this topic. I think HBP was just relating to a previous post where we talked about using that method on higher temp bisque clays where the glaze doesn't adhere very good and a good gel can help, sometimes it isn't needed though in high clay content recipes. Of course the drying time is much longer, but if you want the surface in much better shape it's something you have to consider. As shown above in the picture. I gel some of my glazes using this method and some I don't. Depends on the slurry after I mix it up, if I find it is plenty thick, I don't adjust it, if I find its not as thick and more runny, then I add the vinegar to gel it. I bisque to cone 03. When I bisque my black clay, I bisque it to cone 02.

 

Of course this only applies to the dark stoneware bodies I use. When I worked with porcelain everything was much easier. Super fast bisque to cone 06.

 

I think the main thing that Giselle needs to do is just add small drops of the epsom salt like John Britt does in his video. It should get her slip back to the workable state.

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I would have thought a glaze that has gelled is super-suspended. Maybe I am thinking about it in the wrong way. I suppose there probably is a difference between how particles float in the water and how viscous/jelly a liquid is.

Complicated.

 

I was relating to the vinegar in the slip maaan :D and my backwards advice for not remembering the facts properly. 

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I have a glaze that is super gelled, it won't dry on the pots and won't run off the hot waxed bottom. I have tried taking the standing water off the top and adding sodium silicate, but it doesn't get any runnier. Add MORE Sodium silicate?  What would be the results of adding too much SS?

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B-mix by itself is thixotropic to start with (read slightly deflocculated). Do you really need the vinegar? If you were using it to keep the stink down, peroxide also works without doing anything weird to suspension properties.

I took a workshop from Steven Hill years ago when he was still working cone 10, and all his slip work was done with watered down b-mix on his b-mix pots. He was careful to say that he did not deflocculate the decorating slip because it messed badly with his reclaim.

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I think the main thing that Giselle needs to do is just add small drops of the epsom salt like John Britt does in his video. It should get her slip back to the workable state.

 

I wish I had tried that to see if it worked, but before I posted I had already dumped out the 12 oz or so of weird slip, cleaned out the jar, and remade it just with reclaimed clay, water, and a splash of vinegar. It's absolutely lovely and I've been slip trailing like mad. 

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Diesel: I dont reclaim the slip. I'll try hydrogen peroxide though instead of vinegar, that's a good tip. I didn't want to use bleach, but I can't handle the stink.

 

What did the vinegar do to the reclaim?

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The purpose of the video above really has little to do with suspension. It's all about the gelling, which in my opinion isn't at all necessary for everyone. It's just one way of doing it. He said that the glaze has 20% kaolin in it, which would keep the glaze suspended quite well without adding anything to it, as long as he didn't add so much water to it. Add enough water to any glaze and it will settle. While the gelling does prevent drips, the down side of the method he's using is that he's now got a glaze with a high water content, which means it will dry very slowly. For someone like me who makes thin pots with up to 4 layers of glaze, that kind of drying time wouldn't work. If you watch closely, his mug stays shiny and wet the whole time he's talking after he dipped it, and he only dipped the outside.

Agreed, this is not always necessary. It should be noted that Tony Hansen is troubleshooting his own formulations for Plainsman clays, and is showing work arounds for problems that can be encountered with them. He likes to do two things.

1) formulate clays with a high percentage of native materials particular to southern Alberta, Sakskatchewan and northern Montana that can be heavy on the sulphur and carbon that do indeed play havoc in the form of pinholing (loves me that Plainsman box in the background!)

2) formulate mid-fire glazes heavy on the chemically consistent materials like Frits, as opposed to minerals like Gerstley Borate. The Ferro frits we get here settle like crazy.

He shows one way of getting around the problem, but I know not everyone works the same way. The dude isn't a production potter, he's a chemist. Fortunately for us all, a darn good one.

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Diesel: I dont reclaim the slip. I'll try hydrogen peroxide though instead of vinegar, that's a good tip. I didn't want to use bleach, but I can't handle the stink.

What did the vinegar do to the reclaim?

He talked about sodium silicate, but deflocculants would build up over time and they'll do what your first batch of slip did. Clay that absorbs too much water too rapidly is a pain on the wheel.

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Hmmm. Okay. I use vinegar a LOT in home and studio, and now I'm trying to remember if I dumped some in my reclaim bucket awhile back. That may have been why I was having so much trouble with my first reclaim batch. I'm drying it back out to start over, 40# of clay that I already slaved over.

 

Well if it's funky even after that I'll just use it for plant pots then and do crazy things with texture etc. Use it as a canvas to fearlessly experiment and play. :)

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Joseph: I've been learning to throw since late October. I had so many hangups about throwing that not giving up was a huge effort and I could actually feel the tension ruin pot after pot after pot. I scraped everything I made off the wheel until mid-Feb when I overcame all that mental junk and had my first successful pots. The good news is that NOW almost all my reclaim is from trimming, not failed attempts at throwing. :)

 

P.S. What an awesome last name you have for a potter! Unless that's a screen name. Lol

clay lover and Joseph F like this

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Joseph: I've been learning to throw since late October. I had so many hangups about throwing that not giving up was a huge effort and I could actually feel the tension ruin pot after pot after pot. I scraped everything I made off the wheel until mid-Feb when I overcame all that mental junk and had my first successful pots. The good news is that NOW almost all my reclaim is from trimming, not failed attempts at throwing. :)

 

P.S. What an awesome last name you have for a potter! Unless that's a screen name. Lol

 

I did something very similar when I started throwing. I would just take every pot off the wheel, ball it up, clump it up into arches and let it dry with plastic over it, then wedge it and throw it again. 

 

I am glad your having so much success with throwing, your pots in the gallery look great. 

 

My current last name is Rosenblatt. It is an adopted name from my father's father. My wife and I made a family decision to change our name. One of the main reasons was discrimination, and a lot of hate was aimed towards me as I grew up because of that last name. It only made me stronger as a person, which developed me into who I am now, but our son is a lot more tender hearted like his mommy, and we figured he would have enough issues growing up, much less adding another one, so we made a decision.

 

We wanted a name that didn't have an origin or nationality. We also wanted a name that wasn't religious. So we started coming up with names and then googling them to see if there was an ancestry to them. We had a list and we went down the list with our son, who is 4 almost 5. When we said Fireborn he got really excited about it, "Yea SOLOMON JOEL FIREBORN!". We discussed the meaning of it, it relates to birth of dragons, and pheonix's who rise from the ashes and are born again. That is how we feel about giving our son his own legacy and a new name that he will forge his families future with. So we went with Fireborn. I didn't realize until later after we filed the paper work that it is a really cool name for a potter as well. We should be Fireborns by the end of September/Ocotober. I just went ahead and changed it here because that's who I will be in the future. He already tells people, "you can call me Solomon, or Fireborn." hahah. It is pretty nerdy/awesome last name, but it just sounds unusual because no one has ever seen it used as a last name before.

 

It fits my son well....

 

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This topic always makes my head spin! Can a glaze get so messed up ,flocculated-deflocculated ,that you have to trash it and start over?

 

Yes a glaze can get too flocculated that you have to throw it out. Tony mentions that if you flocculate a glaze to far it is nearly impossible to get it back to the state it should be and it will never give consistent results. As far as deflocculated, I have no idea. No experience there yet. 

 

I once flocculated a glaze on accident and it was like marshmellow cake in the bucket. Literally could pick it up out of the bucket with your hands and hold it and it stayed in form... 

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