Newbie Tweaking Flocculation

[mrcasey]

I'm new to glazing and mixing up my own glazes.  I've recently
been experimenting with a clear cone 6 electric base (5X5) with
added mason stain.  My intention is to dip.

 

I was just reading a Pete Pinnell article in which he states that,
"I need to flocculate almost all my glazes, if only just a little."

I can see extreme cases of over flocculation and deflocculation -
but how will I know if my glaze needs just "a little" as Pinnell
suggests lots of glazes do? 

 

I've watched the John Britt video.  The deflocculated glaze
clearly needs flocculated.  The over flocculated glaze, though,
doesn't look that much different to me than regular glaze.

 

Experienced potters can tell by looking and touching.  Is there
some measurement I can take to tell me if my glazes need a little
tweaking?

 

Casey

[neilestrick]

Post the recipe. Generally, if the clay content is under 12% or if it's high in frit, I would flocculate with epsom salts. Ultimately it's all about whether or not the glaze is settling out quickly.

[clay lover]

I think I have the opposite issue, a glaze that seems to be over flocked.  Thick in the bucket, adding water does not thin it, goes on thick, no matter how fast I dip, stays wet on the pot, runs a lot, is fluffy and loose when dry on the pot. 

Are these symptoms of over flocking?  How does a glaze get that way?   Other glazes I have used Epsom  salts in to cure settling and hard panning with good results, this glaze I am flummoxed with.

 

This seems to be a confusing question for lots of potters, and the articles don't seem to clear it up much.

[High Bridge Pottery]

To thin a glaze out you can use sodium dispex or similar deflocculant 

 

I think the slight changes in the floc/defloc equilibrium are all down to personal preference of how you like your glaze application to be.

[neilestrick]

I think I have the opposite issue, a glaze that seems to be over flocked.  Thick in the bucket, adding water does not thin it, goes on thick, no matter how fast I dip, stays wet on the pot, runs a lot, is fluffy and loose when dry on the pot. 

Are these symptoms of over flocking?  How does a glaze get that way?   Other glazes I have used Epsom  salts in to cure settling and hard panning with good results, this glaze I am flummoxed with.

 

This seems to be a confusing question for lots of potters, and the articles don't seem to clear it up much.

 

Post the recipe.

[mrcasey]

Here's the recipe:

 

20%  WOLLASTONITE     
20%  FRIT 3134        
20%  KAOLIN  (EPK)         
20%  SILICA           
20%  POTASH FELDSPAR 

_______

+ 10% Mason Stain (either Lavender, Praseodymium, Bermuda, or Hazelnut Brown) 

 

I'm using about 70% water by weight and going with a specific gravity of 55

 

 

thanks,

Casey

[neilestrick]

With 20% EPK it shouldn't have much problem staying suspended. But if it does settle more than you'd like, dissolve a tablespoon or two of epsom salts in a little water and slowly add it until you see the glaze thicken a little bit.

[mrcasey]

Might it need deflocculated?

[Min]

 

 

I'm using about 70% water by weight and going with a specific gravity of 55

 

 

thanks,

Casey

 

How are you measuring your sg? 55 doesn't sound right, approx 1.5 to 1.7 range for dipping. My guess is you are not adding enough water for this recipe. 

[neilestrick]

Might it need deflocculated?

 

Probably not. Glazes needing deflocculating are not nearly as common. If they are really high in feldspar or clay, like 40-50% feldspar or 25-30% clay, then they can dry very slowly and need deflocculating if you don't want to wait on them, but this glaze should go on nicely. The only 'if' factor is how the mason stain affects it. They all behave differently as far as how they suspend and take water.

[Chantay]

I keep a bunch of test tiles in my glazing area.  I will check the glaze after stirring by dipping in the test tile. Hold for a three count. Look at it closely as you pull it out of the glaze.  You can see the thickness and how it adheres and flows down the tile.  With practice this will tell you all you need to know.

[mrcasey]

Min - I think that those 2 digit numbers are degrees baume.  I find the "units" you're talking about more intuitive (1.55 X density of water, etc.) but my buddy seemed more inclined to use degrees baume; so that's what we used.  In their mixing instructions web page, Laguna also uses baume.         

 

Casey

[clay lover]

 Neil, this is the glaze that  I wonder  might need to be de- flocculated.  I appreciate an y assistance. other that it's difficult bucket behavior, I also notice the standing water on the glaze is the color of ice tea.  The fired results looks fine. 

 

F-4 feldspar    38

Whiting            14

Zinc oxide        12

Ball clay             6

silica                 30

 

 

add

Copper carb     2

Bentonite          1

[Babs]

Claylover, you could maybe just take a jugfull of your glaze and  add a drip at a time of your defloc., agitate and see if it stays insuspension. If so do the bucketful. Drip at a time though, pos to go over with defloc.