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Mark C.

Specific Gravity-Glaze Thickness Tools

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Every week or two I mix glazes ,lots a of glazes. Having the right tools makes this a snap

There are basically 3 tools to aid you in getting glaze the right thickness.

˜One is the hydrometer

Another is the Graduated ML cylinder-this is filled to 100 ML and weighed

The last is the viscosity cup

I gave away my cup recently and have yet to buy another

They can be had here

https://www.amazon.com/TCP-Thickness-Viscosity-Measuring-Viscosimeter/dp/B00IL7DVNW/ref=sr_1_2?ie=UTF8&qid=1495322530&sr=8-2&keywords=viscosity+cup

 

A good electronic scale is also a must

Here is one that works fine and is cheap

https://www.amazon.com/gp/product/B004164SRA/ref=ox_sc_sfl_title_48?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

this one weighs up to 15#s

https://www.amazon.com/gp/product/B009EUPMFK/ref=ox_sc_sfl_title_47?ie=UTF8&psc=1&smid=A37RGE1MLU3I6K

I have and use this scale and it works great

https://www.amazon.com/gp/product/B001NE0FU2/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

With all these devices you mix up the glaze well and then use the tools.

If you have a hydrometer like the small one on right in photo and the photo with the orange type you will need to go buy another as this type is for making beer and alcohol and is not the right scale.

I only included this to show its the WRONG TYPE of hydrometer

 

Speaking of scales I use the one in the close up photo. Many glazes fall into the 1500ish  range

 

I have really like the ML cylinder and weighing it as its very quick and less errors. I use it almost weekly on a few glazes.

Most of my glazes have a range and do not need the fine-tuning of these tools but a few are very touchy and I use them every time I make them

A few other notes mix your glaze and let it sit as it take about 6-12 hours for all the small particles to get wet-then remix and measure.

If you have a glaze that settles out do yourself a favor and buy some magma

It,s the best product I have ever found that cures settling

You can get it here

http://www.bigceramicstore.com/tools-supplies/glaze-making-equipment/magma.html

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Edited by Mark C.

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Good Info Mark

 

It seems I was mistaken in thinking I needed a scale that measured 0.1 of a gram

One gram is smallest measurement you should ever need in glaze making

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I find a scale that measures in tenths of grams very useful for glaze testing. Less than a gram of chrome for chrome/tin red tests, often less than a gram for copper, cobalt, stains, and other colourants when the base for the test glaze is 100 grams. Agree with Mark when you are doing up a large batch of glaze you don't need to go with less than a gram.

RonSa and Callie Beller Diesel like this

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I find a scale that measures in tenths of grams very useful for glaze testing. Less than a gram of chrome for chrome/tin red tests, often less than a gram for copper, cobalt, stains, and other colourants when the base for the test glaze is 100 grams. Agree with Mark when you are doing up a large batch of glaze you don't need to go with less than a gram.

Min how small are these tests-less than 500 grams total?

I have used my old triple beam for those smaller tests.

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I find a scale that measures in tenths of grams very useful for glaze testing. Less than a gram of chrome for chrome/tin red tests, often less than a gram for copper, cobalt, stains, and other colourants when the base for the test glaze is 100 grams. Agree with Mark when you are doing up a large batch of glaze you don't need to go with less than a gram.

Min how small are these tests-less than 500 grams total?

I have used my old triple beam for those smaller tests.

 

 

Yup, usually 100 or 200 grams for first test glaze then work up from there. For chrome/tin reds as an example since the chrome is usually only 0.15 I go to the hundredths. Even at 500 grams for the base the chrome would only be 0.75 so go to the hundredths even for that amount. My fake celadon uses 3 stains, all in tiny amounts like this. Yeah, I use an old triple beam for small amounts too. (makes me appreciate the digital scale even more) 

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ok you guys, i am ready to consider one of the scales mark recommends.  i have looked at the words, pictures, videos and do not see any measurements on the flat platforms on several of them.  customer comments include some references to being unable to read the numbers if the plate is too big.  

 

i usually weigh things using a thin plastic cover that supermarket bakeries use for large round cakes.  it measures just over 7 1/2 inches at the bottom.  if i fill it, will i be able to see the numbers?

 

mark, the one you use has an electric cord which i would prefer.  did you buy it?

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Ron

Thats the one I use-the battery has lasted for 4 years.

Never needed the charger.

Its got huge letters and a tare function -Incrediabliy accurate -super light

its smallest measurement is 1 gram

I tend to use it in the house a lot as my Ohaus electronic (5,000 grams) is in studio

I do a lot of mail weighing and ups with it.

Edited by Mark C.

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The thing about the electronic scales (and I should say I learned about them here) is they about a zillion times quicker to use than any triple beam-have larger weight limits and great easy to use tare functions 

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Mark, I have that scale too and had it for a good few years, still using the original batteries that came with it. I was showing old lady that its easy to read the numbers with the large cover she was talking about and where to get the adapter she was asking about - Sorry, I didn't mean to step on your toes.

 

When I realized I needed a scale that reads 0.1 of a gram I purchased this one (for 100 gram tests glazes). Its about the size of a paperback book.

https://www.amazon.com/0-1g-Mini-Electric-Back-Lit-Stainless-Batteries/dp/B01DGEWHN4/ref=pd_sbs_79_6?_encoding=UTF8&pd_rd_i=B01DGEWHN4&pd_rd_r=5SQ9489CE8CZT3KHVRBH&pd_rd_w=srHVi&pd_rd_wg=nfIaJ&psc=1&refRID=5SQ9489CE8CZT3KHVRBH

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From a big discussion we had on scales back in December.

 

Saki, on 08 Dec 2016 - 12:41 PM, said:

Hmm, I am intrigued by popularity of digital scales. I had learned that they weren't as accurate as mechanical scales (which are accurate to 0.1g). But I guess that is not so anymore? I ask because I am still testing glazes, so with small batches I feel more comfortable with the extra precision. Also, can digital scales be calibrated like a mechanical scale?

 

My reply:

 

Digital scales are very accurate. I have a 300 gram one accurate to .01 grams. Got it off EBay for about $5 USD. This level of accuracy is useful when measuring out small quantities of very powerful (and usually very expensive) colouring oxides.

 

How do I know it is accurate? For a couple bucks more on EBay you can get a calibration weight to test the accuracy whenever you want. I do this regularly so I can verify that it is accurate.

 

I have found that after 3 years of hard use and banging around in my toolbox it has lost a few hundredths of a gram of accuracy. I can put up with that, but I got another one just in case it goes kaput.

 

Also, I have found that when weighing hot objects (eg, test bars right out of the kiln) it gets a bit flaky. These issues are minimal in any case.

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For you small glaze testers out there back in school (ceramics ) we learned that 500 gram tests are so easy to screw up that you really need to be careful. Most of my tests are 1000 grams.

As the test gets smaller the errors get larger -just keep this in mind

Pres likes this

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I just received  a package of Magma to try out & it mentions to follow the directions carefully. Hope I can find them online as there was no instruction sheet in the box. I have the scales and a hydrometer & the graduated cylinders so I think i'm all set- after I find those instructions!

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1 hour ago, terrim8 said:

I just received  a package of Magma to try out & it mentions to follow the directions carefully. Hope I can find them online as there was no instruction sheet in the box. I have the scales and a hydrometer & the graduated cylinders so I think i'm all set- after I find those instructions!

http://shop.brackers.com/MAGMA-Miracle-Anti-Gravity-Multipurpose-Additive-P3316.aspx

terrim8 likes this

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A few tips on Magma use-I mix some up and keep in in a sealed container. Its looks and feels like snot.The small amount of copper keeps it from going bad.

I make it with HOT water. It mixes in glazes best with warm water.You can add it to say a small amount of hot water then into the cold water in a glaze bucket once it diluted. Just make sure your glaze is already not top thin to add water to. I often heat a little glaze in an old pan and add this to that if the gravity is already right.Then it dissolves well and add that back into larger batch.

terrim8 likes this

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