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Mixed My A First Batch Of Glaze


Pugaboo

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I mixed my first batch of glaze from scratch today, with oldlady holding my hand over the phone. LOL

Using the speaker on my phone was great EXCEPT that I was wearing a mask.

Mmffhrrmddsserfffvnmm.

Oldlady was very good at deciphering my muffled talking. 😀

I mixed up a 1000gram batch of Shiny White Old Lady < giggle> that's what I am calling it anyway. Oldlady was kind enough to share her glossy white glaze with me. Dhpotter and Min have also been generously helping with my glaze education. I've been learning by leaps and bounds with all of their help. The true test, of course, will be glazing a test bowl with the white and firing it.

 

I'm kind of nervous about that... Will I pass or will I fail?

 

T

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You will save so much money making your own glazes,  it will give you great satisfaction.  Every once in a while I will buy a premixed glaze because the sample is interesting,  I am usually disappointed.  The glazes I make are much more reliable.    Denice

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Thank you everyone, it's a BIG step for me. Just ask oldlady who has been trying to get me to do this for 2 years!

 

I'll let you know once I've put it on a test piece and fired it whether it's a no biggie or not!

 

I started with white since I had most of the ingredients already and I am almost out of the coyote white I have been using. It was basically a choice to either buy the missing Minspar or buy more of the commercial coyote white. If I got this right the next I will try is a clear since that is the other glaze I use a lot of.

 

Will glaze a bowl tomorrow and fire it my test kiln then we will see!

 

T

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it is true that i sent several 100 gram batches that only needed water added to make glaze.  never happened.  fortunately i sent 100 grams of bentonite so terry used that and new ingredients she bought and really did it.  sieved it 3 times and all.  CONGRATS!!!!

 

now to see what it looks like tomorrow.  the addition of water is always a "it depends" situation.

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You will save so much money making your own glazes,  it will give you great satisfaction.  Every once in a while I will buy a premixed glaze because the sample is interesting,  I am usually disappointed.  The glazes I make are much more reliable.    Denice

I always thought mixing my own glaze would save money Denice - until I costed it out and even a basic low fire transparent was barely cheaper AND I calculated the costs proportionately to the quantity in the recipe! The only advantage I could see is if anything goes wrong, you do at least know the glaze ingredients and might be able to adjust the recipe.

ALSO my experience of a premixed transparent is contrary to yours - I have one that is virtually foolproof and totally forgiving of any poor application techniques. If I could find a recipe that achieved the same success I'd go for mixing my own again, but I'm still looking. At least, having gone through the exercise of costing out a recipe I now know which ingredients are the expensive ones and which the cheaper ones!

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LOL.... yes oldlady sent me some pre mixed sample packets of her glazes, what she didn't tell you was I STILL managed to mess up the one I tried. Hence the other couple packets are still sitting in the cupboard. But now you know why I have a fear of mixing my own. I am hoping this time is different.

 

The Bentonite was a welcome surprise since I didn't have any then remembered a packet of that was in the box she sent as well. Oldlady to the rescue once again!

 

Heading down now to glaze and fire a bowl in my test kiln.

 

T

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Go team OldPug  :D Keep mixing and melting those rocks Pugaboo.

 

Celia it probably costs more for lowfire glaze ingredients but I can get a 10kg glaze bucket for £8-12 using raw materials when it is £40 and up for premixed. I think cone 10 is cheaper on ingredients but it sound strange that you can't make it for less.

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Here is a picture! Not an A+ result but I'd say a solid B-. I got the scalloped rim a little thin as you can see OR the test kiln didn't stay hot enough at the end to let the glaze flow a bit more to fill in the scallops equally. I brushed this time, next I will dip a mug and hope for improved results. The glaze brushes on differently than the commercial stuff so will take some getting used to that and allowing for it as well. This white is actually whiter than the coyote white I have been using and I like that. This is a glossy white yet doesn't seem harsh either.

 

The next test for this glaze will be to put a small transfer on the test bowl and fire that. Some glazes play better with transfers than others. Will be exciting to see the results.

 

T

post-22921-0-19757200-1469650142_thumb.jpeg

post-22921-0-19757200-1469650142_thumb.jpeg

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Go team OldPug  :D Keep mixing and melting those rocks Pugaboo.

 

Celia it probably costs more for lowfire glaze ingredients but I can get a 10kg glaze bucket for £8-12 using raw materials when it is £40 and up for premixed. I think cone 10 is cheaper on ingredients but it sound strange that you can't make it for less.

Think I must have opted for a complex recipe to do my comparison exercise. Will look for another recipe and go through the exercise again!

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...I got the scalloped rim a little thin as you can see OR the test kiln didn't stay hot enough at the end to let the glaze flow a bit more to fill in the scallops equally.

T

 

I am not so sure from the photograph.  It may be the other way around; one could interpret the image as the glaze moved away from the tops of the scallops and it is thin because the glaze moved.  Note that there seems to be some additional glaze just below the rim on the outside.  I can't quite make out the inside situation. 

 

Make several more pieces just like the one in the photo and glaze one the same way as the one reported here.  Another were you add more to the high points and repeat the firing time temperature profile as the one reported.  Compare the results. 

 

Overall I think the glaze prep is better than a B. 

Application is always the most difficult part of glazing. 

 

LT

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Here is another angle of the dish. The only time I had something like this happen with the commercial glaze was when I had thinned it too much with water so the lip of a cup was shiny but had the clay peeking through. The dish is a quickie test dish that I keep a stack of in my studio. They take 2 seconds to make and I don't even try to make them perfect since I just use them for testing glaze colors for custom order requests.

 

T

post-22921-0-44278600-1469656469_thumb.jpeg

post-22921-0-44278600-1469656469_thumb.jpeg

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If you are going to be brushing glazes on I would mix those glazes with a brushing medium rather than water. Glaze dries slower and flows from brush to pot easier. But once you get the hang of dipping or pouring glazes I doubt you will want to go back to brushing since it takes so much longer.


 


My guess would be the glaze is too thin on the high points of the scallops, maybe application, maybe overfired?


 


If I may make another suggestion, if you are not already doing it, for your dipping test I would measure the specific gravity of the glaze and make note of that plus the length of time you dip the pot for. Makes it easier to replicate successful glazing on future pots until you get to know the glaze well.


 


What is the pink tint from? 


 


Good stuff for your first go at this!  :) 


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My method of mixing glazes is to measure the amount of water I use for each 100 grams of solids in the recipe.  I start with a water to solids weight ratio of about 0.6 and then measure each addition of water until I reach a mixture that seems right.  I record the ratio of the total water used to the weight of solids used in my glaze notebook.  If the application is easy and the glaze fires fine, that ratio is the target for all future batches.   Scaling the recipe to larger batches is easy now  since I know how much water will be required for any size batch. 

 

Measuring the SG of the final glaze mixture is gives you a way to check if a glaze has lost water from either use or evaporation. 

 

LT

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Min, YES! Oldlady said to ask you about specific gravity and how to measure it and all that. Do I need to get a hydrometer or something?

 

I tend to brush the first coat of glaze on because I use a lot of textures in my pieces and found I got lots of pinholes if I just dipped them. A thin coat of glaze brushed on then a quick dip works well. I also tend to use different glazes inside than outside of pieces as well which make dipping difficult. I do dip my mug bodies dry then dip the handles in the contrasting glaze. I also pour the inside of some items and then brush the outside. Some pieces there is just no way to simply dip them so brushing has to be done.

 

The pink is just reflected light from my cellphone most likely the shirt color I had on reflecting back into the dish. Did not color correct or use my photo set up just plunked it on the table and snapped the shot. The dish is pure white except on the edge where you can see the creamy color of the clay showing.

 

T

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thanks min for reminding me that i did not even mention the length of time of a dip.  someone with real experience in dipping bisqued pots should chime in here to tell terry to count to ?  while dipping the pot in the glaze.  and specific gravity and all that other technical stuff.  she has the smarts to understand it, i do not have any smarts re it so please, min and anybody else, chime in.

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For specific gravity testing there is more than one way to do it, this is what works for me. 

 

Take a see through tall skinny container, if you can get a graduated cylinder then that would be perfect, if not then just a clear plastic throwaway cup is okay. Put it on your scale and tare the scale to zero. Now add water until you have 100 grams exactly. (when you get close to 100 grams you can use a wet sponge and just squeeze in a drop at a time). Now get down to eye level with the water level and mark a line on the container. Next dump out the water and dry the container then fill it up with well mixed glaze to exactly the same line and re weigh it. It will weigh more than the water, probably in the 140 to 160 gram range. Divide the weight by 100 and you have the specific gravity. 1.45 to 1.5 is the common SG range, glazes with a large amount of frit in them can be higher than that.

I would just go with what OldLady suggested for water content and measure that SG and go from there if you find you need to change it.

 

How long you dip your pots for depends on a few things. How hot you bisque your pots, if they are bisqued to 08 they are going to soak up more glaze than 04 for example. Also, pot wall thickness for the same porosity reasons. Plus, the type of glaze it is makes a difference too. Some clear glazes like a quick dip, other glazes like a longer dip or 2 quick dips, multi layered glazes are usually thinner too. Just have to try it and see what happens. 

 

What I would suggest is to take a bunch of test tiles and glaze 2 of them with 1 dip for a count of 3 seconds, let them dry then take one of them and scratch through it to see the glaze thickness. Now take another couple test tiles and do the same thing again but this time dip for a count of 6 seconds. Could do again for 8 or 9 seconds. Also double dip and see what happens. (if double dipping do the second dip just as soon as the sheen is off the glaze from the first dip). Fire the unscratched test tile and keep the other one with raw glaze on it for a visual reference of how thick the glaze is. (use tall test tiles about the same thickness as your pots tend to be and leave room at the bottom for running) You could add a stripe of underglaze colour or slip on all the test tiles while you are doing them to see how it plays with the glaze.

 

Sounds more complicated than it really is, doesn’t take long to run the SG weight test or do the test tiles.

 

I'm wondering if you slightly dampened your textured bisque then dipped it if that would solve the pinhole problem? Or a thinner glaze but dipped for longer? Could also try deflocculating it but maybe we should put that on hold for a bit.

 

Do you need a brushing medium recipe?

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Min - I do the SG test with glaze I know is mixed correctly... Yes? Then record that and use it to verify that "most" of my glazes are within the correct parameters before using?

 

To glaze, this is my current process:

 

Bisque to 04

Wax bottoms if needed (I like to do waxing first so then its easy to see if I missed a spot or have a spot I don't want)

Rinse quickly with water (either in a bucket or more often a quick swish under running faucet)

Let sit while I get my glaze ready (open containers, mix, etc)

Then either brush a couple thin coats on ( I brush east to west then north to south)

Or dip (I have found a count of 1001, 1002, 1003 works for most of my current glazes. There are some Mat glazes that this is even less since they tend to be chalkier in their application)

Or pour along with brushing or dipping (mugs, vases, pitchers, etc I use a plastic pitcher and pour the glaze inside then immediately pour it back out. Let this glaze dry which is usually pretty quick then either dip if I have an even rim or brush if it's variegated.

Set to dry

Use a use a piece of carpet glued to plywood to clean off the bottoms

FIRE!

 

YES I would like the brushing medium recipe you are so kindly offering. I really appreciate it.

 

T

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PugaBoo,

 

For the test tiles I sent you, all of them were dipped for 1 second then the R top corner was dipped for another 1 sec. Making it 2 sec on the top R hand portion of the test tile.

 

I initially put 3 ounces of water per 100 grams of dry material. I let that sit overnight then mix really well. While I am mixing is when I determine to add more water. When the glaze goes to production is when I will take the SG - the way Min says to do it.

 

Personally, I think the glaze moved away from the scallops. On the inside of the plate right under the scallops it looks thicker.

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