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AlanJanzen

Glaze Question - Strontium Crystal Magic

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First of, I did see a few posts about SCM from the past, but it seemed most of them sputtered out before it got into some of the questions I wanted to ask here.  Hope that's ok that I started a new thread.

Does anyone have any pictures or info on how SCM cool or warm look on their own?  I'm mixing glazes myself for the first time and I think I was given some wrong advice as to how much water I should start with.  After reading through the glaze section in John Britt's book I'd say I started with about 4-5 times more water than the 1 pint recommendation for 1000g of dry materials.  I've been cutting water off the top of the glaze, but it still seems runny to me and the second set of glaze tiles still looks like more of a stain than an actual melted glaze at cone 5. 

So I have a few questions related to that:
 - Should I start over with a pint of water or continue to cut water off the top?
 - Is this just what it's supposed to look like? (SCM cool on left, SCM warm on right; dipped 5 seconds at a time in 4 layers getting thicker towards the top)
 - Do I need to be firing to Cone 6 instead?  I'm in a studio where I don't control the firings, but I know it's to Cone 5 with a 30 minute hold at the top.
 

Any advice or comments would be appreciated.  Thank you!

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Really rough ballpark figure for water would be 70-80% of the weight of the glaze materials. So 1000 base would take approx 700-800 grams of water. If you added 4-5 times the original pint called for that would be around 2100 grams of water. Two to three times as much as you probably need. Strontium is mildly soluble, don't know how long it takes to leach out of the material and into the water. (I find it way easier to work both glaze materials and water in metric, 1 gram of water for all intents and purposes is 1 ml.) 

Biglou13 likes this

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Good to know, so the pint may be a little low to begin with, but will give me more room to add water on the other end?  

Thank you for the info.  Had a feeling it was just way too thin for application at this point.

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6 hours ago, AlanJanzen said:

Good to know, so the pint may be a little low to begin with, but will give me more room to add water on the other end?  

Yup. I would mix it with enough water to get it through a sieve but not so thick that it's a pain to do. Then start thinning it down to where you want it. When you get it sorted out take the specific gravity so you can replicate your results.

I played around with this glaze a few years back, by itself it seemed  under-fired and matte. I think it would be more accurate to think of it as a glaze modifier rather than a glaze that could be used alone. (silica levels are low so it wouldn't be durable on it's own either)

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Keep in mind that Steven Hill (the author of the common iteration of this glaze) uses it as a base, and sprays a whole bunch of things on top of it.  It's magic because of the way it reacts with other glazes, not because it's particularly special by itself. 

 

(Although I agree, your tiles look a bit thin.)

clay lover likes this

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I have the video series by Steven Hill. I bought it mostly for spraying knowledge, but he did talk about SCM. He said it makes up a large portion of the glaze he puts on his pots. I think somewhere between 30-50% of the total glaze is SCM. So it needs to be thick. I tried it for a bit, but I never really had much success with it so I just quit using it. @dhPotter has more experience than me. I tagged him so he might come read about it. But I agree with the best. Your SCM is very thin and it is never pretty by itself anyways.

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Thanks for all of the advice.  I went ahead and remade the SCM yesterday starting with a pint of water.  I mixed them up and left them sit overnight. I will sieve them this afternoon when I get some time in the studio.  I do have a spray set up ready to go, but I'll probably dip the first tests and maybe I'll do a few other tiles with something layered over the top just to see how they turn out.  

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SCM warm has more personality than SCM cool, I apply it on the thick side.  I like to play with it, I will glaze some pots that I am not crazy about and then layer different leftover glazes on it to see what will happen.  I keep them around for my relatives to pick from when they come around asking for a piece of pottery.  Have fun!  Denice

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hey AlanJanzen, 

SCM by itself is not attractive. The surface will be dry and scratchy.

Yes I use SCM warm and cool on nearly everything I glaze. Spray the SCM first and make it about 30-40% of your total glaze thickness. I have specific gravity set at 1.47 for both the Warm and Cool. Test every glaze you have over SCM. You will be amazed at the color variations with your different glazes over SCM. Any glazes with Strontium Carb in them will react better over SCM. Remember, copper and cobalt containing glazes go over the Cool. Iron glazes over the Warm.

Steven Hill pairs (JJF) Jen's JuicyFruit Warm and Cool with the SCM. After all glazes have been sprayed on your piece, hit the piece with short spray bursts of JJF Warm or Cool depending on the other glazes. I give the banding wheel a spin and no more than two revolutions over the whole piece. Be sparing with the JJF. The JJF will make the surface soft and smooth. I have found without the JJF the surface is scratchy. On your test tiles allow room at the bottom for glaze runs especially if overspraying with JJF. It is not called Juicy for nothing! 

Sometimes, I will spray both Warm and Cool on a piece because I want to use a green glaze to accent an otherwise iron red glazed piece. Take a look at my Evolution gallery. You will see examples on some mugs with cool and warm on the same piece.  

Use SCM as accents to create different colors from your glazes. You don't have to spray the whole piece with SCM. 

The RO8 is Red Orange that I have added 8% more silica. HFAI = Hannah's Fake Ash Iron, C= SCMCool; I = SCMWarm; PSF = Pete's Sea Foam.

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Edited by dhPotter
AlanJanzen, Joseph F, Babs and 1 other like this

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