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Glaze Mixing Question - Small Batch Vs Large Batch Differences, Because Of Mixing Technique?


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I have been mixing small batches of glaze like 1500-2500 gram batchs with an immersion blender or hand blender. It mixes fantastic.

 

This is my process:

 

I put in 2/3 the amount of water needed into bucket. I weight and pour each ingredient into water. I then let it soak in until its fully submerged or all clumped up nice. I then mix with hand blender for a long duration. I add water and continue to mix until I can stick a tile in and there are no differences in surface or any grit or ingredients showing. I then sieve this batch and repeat process. I wait 24 hours then use the glaze the next day only stirring it up with a mixing tool by hand.

 

My question is, when I mix a larger batch of glaze say 5000-7500, I get variations in the glaze, like minor speckling. The base glaze always comes out pretty much the same but I have some iron speckles in the larger batches always. I am very careful to measure exactly right so it isn't that I am adding to much iron in the larger batches or anything like that. It puzzled me for a few months now, but I think I know the answer, but I just wanted to run it by you pros.

 

When I mix the larger batches I use a drill mixer, but I repeat the same process as above. However for some reason I think the drill mixer isn't doing the job as good as the immersion blender is. Does this seem like it could be the issue? Cause I have mixed numerous buckets and had subtle differences that I don't really want, but I am ok with the mistakes because I use them as under layering glazes that produce some beautiful results.

 

I am not sure how to bypass this, I have been thinking about doing extra work and mixing up 3x2500 gram batches with the immersion blender then pouring them all together in a big bucket and mixing again with a drill as I can't stand some of the speckling on my white glazes that I want to only have the clay body specks showing.

 

Have any of you noticed anything like this? Or am I just insane? I am literally at the point where I get differences between a 5000 gram batch and a 2500 gram batch and the only thing I am changing in my process is the mixer. That has to be it?

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Is the paint peeling off your drill mixer at all? Contamination from that, perhaps?

 

I've found that some materials like red iron oxide need to be sieved more than mixed. What mesh are you using?

 

I weigh out my materials into half the water I'll need, and allow to slake for an hour or two (usually over lunch or some other break) and then mix it enough to get it to a pouring consistency. I run it through a sieve twice, adding water to the mix to rinse the sieve and bucket. I give it a hand stir for good measure, adjust the flocculation and consistency as needed and it's good to go. I don't use a drill mixer when making a fresh batch, because mixing through the sieve seems to combine everything enough for even my celadons.

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You know, maybe it is my mixer having a little rust on it in the crevasses or the paint I am not sure, I just know it only happens when I do a larger batch, and the mixer is the only thing I am doing differently. I have never tired not using a power mixer to make glazes. That is interesting I might need to try that method. 

 

I wish they made cheap immersion blenders with longer shafts. I know they make expensive ones, but I burn them up about every 3-4 months mixing so many test glazes I just get the cheap ones from walmart for 20 bucks.

 

I feel so absurd if its just a little rust of paint flaking off. Makes me wanna kick myself. I guess I need to invest in better sieves and better drill bit mixers.

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I use a 80 mesh sieve. But I only use it on my larger batches. I am not really sure I even need to use it with my immersion blender as I never get anything in the screen anyways. I just do it to be sure. However when I use the big jiffy drill mixer I don't get as pure of blend so I have to sieve it. However there still isn't much in the sieve. 

 

I really think its either the mixer isn't working as good as the immersion blender or its small rust coming off into the mix, there isn't any visible rust, but I don't know if in the joints there might be a little. 

 

This is what I have: http://www.axner.com/jiffy-hs-2mixer.aspx

 

I have been thinking about getting this: http://www.axner.com/turbo-mixer-s-24.aspx

 

It seems expensive, but if it really works as good as it claims I am more than happy to spend the 50 dollars on it. At this point I am either going to mix two 2500 gram batches with the immersion blender to get 5000 gram batch, or I am going to buy one of those mixers. 

 

I found a few people on clayart that spoke about the turbo mixers in the past and they said it was 1000x better than the other mixers they had used. I am always skeptical of things so I am not so sure what to do yet. 

 

As always DECISIONS must be made.

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gosh, i learn something new every day.  years ago, i had a stainless rod welded onto a stainless chain.  3/8 in rod, 18 in long.  chain was a little thinner than 3/8 in metal, links about 1 1/2 inches long,  chain about 9 links long, rod welded in the center of the middle link.  

 

that thing spun so fast and so well that the glaze was mixed faster than any other way i had tried.  never tore the plastic bucket, never took more than a fast rinse to clean it. 

 

i think it worked like the turbo gizmo.

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I will let you all know how the turbo gismo works. 3 people on clay arts swore by it and never use jiffy drill mixers anymore. I am ordering it tomorrow and making production batches after I get it. 

 

I am going into production, making pots to sell. So hoping it works well and gets rid of my problem. I can't figure out anything else it could be. Literally the only thing I do different besides larger amounts of glaze materials, but the same %'s. 

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If you have a way of knowing the difference in RPM of the immersion blender versus the Jiffy mixer HS-2, then that could be a clue. Also when you have a larger volume, the container to mixer dimensional characteristics may change enough to make the difference. The Axner description of the Jiffy mixer said it is 304 stainless steel, so I would discount the idea that it is contributing enough iron to make specks in your glaze. The turbo mixer is probably a good route to go since you want to get into production right away. Experiments take time. Best of luck with the new mixer.

 

I sieve through 100 and 80 mesh and never have this issue, although frustration with the 100 mesh can take a toll too ðŸ˜

 

John

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It's more that the 80 mesh sieve breaks up the really teeny clumps, it's not removing (much) particulate. Use the sieve if you have it before you go drop a bunch of cash on something you might not need. My mixer is not stainless steel as yours is, which is why I asked about it. For reasons in the post above mine, the problem is likely not the mixer.

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I have used 

Jiffy PS-1 Mixer

for 35 years-I wear them out=I'm on my 5th or 6th one. I have all the sizes of Jiffys-use them in a 1/2 inch dedicated drill as well as the small ones in a pot shop cordless

They always wear out the outer bottom ring after years of weekly use.

I also use another brand harder to find for hard settling glazes they are Stainless shaft and cast bottom.

I'm a production potter and never have seen any rust on a all stainless jiffy.I make my living selling pots-lots of pots and you do not want any chunks in the glaze

I would run all glaze thru a 80 mesh no matter what. The time you do not is the time that will matter-I know this from the school of hard knocks.

Immersion blenders work great for testing.

Let us know how the turbo works.I have never considered one.

My guess is its not the mixer as to the spots.

Mark

Mark

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Thanks for the idea. I have already ordered the equipment. Got to get the ball rolling. If it doesn't work then I might do that. I don't think it won't work though. My other glazes that don't use iron never have this issue. So I think it is the iron not getting properly mixed because of the blender. I also got the 100 mesh sieve which I don't mind doing the effort if it solve the problem. So I am attacking it from every angle possible.

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I have used iron from 3 different sources. Same issue. USpigment, axner, and a local supplier. That was my first assumption. 

 

I tried high purity, synthetic, and natural and spanish. lol... im a bit of a nut. but i love iron based effects and glazes. All of them left speckles. It has to be the blender, or the fact that my 80 mesh sieve isn't enough. I am just going to use that 100 mesh and get the job done right, besides a big bucket goes a long way its worth the effort.

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The stick blender is a high-shear type mixer. It runs very fast, with very sharp blades that are intended to cut and shear particles into smaller sizes. The drill mixer is just a mixer. It moves stuff around enough that things that are clumped up tend to fall apart, but it runs much slower than the blender, and does not have any shearing action. If you're getting speckling, you need to use a smaller screen.

 

Commercial glaze suppliers have larger volume high shear mixers than can reduce particle size in such a way that they don't have to screen the glazes.

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The stick blender is a high-shear type mixer. It runs very fast, with very sharp blades that are intended to cut and shear particles into smaller sizes. The drill mixer is just a mixer. It moves stuff around enough that things that are clumped up tend to fall apart, but it runs much slower than the blender, and does not have any shearing action. If you're getting speckling, you need to use a smaller screen.

 

Commercial glaze suppliers have larger volume high shear mixers than can reduce particle size in such a way that they don't have to screen the glazes.

 

Thanks Neil. 

 

I think the combination of the new mixer and the 100mesh sieve is going to solve the issue. I am so happy to finally have this issued solved. If you remember I was dealing with this back a while ago and I just sorta settled for it, but when I mix smaller batches with my blender it is beautiful, large batches not what I want.

 

I also need to PM you a quick question about two things. Going to do that now.

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I got my sieve and mixer yesterday. I re-mixed a previous bucket of glaze and that thing makes a huge funnel, you can see the bottom of the bucket that's 3/4 full. I then sieved my glaze with 100 mesh sieve and I had to brush it through with a brush. I then sieved it again, 100 mesh is tiny compared to 80. 

 

Thanks for the help guys. I will let you know the results middle of the week. Going to mix a bunch of production batches tomorrow.

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