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Member Since 10 Nov 2010
Offline Last Active Dec 15 2014 01:42 PM

Posts I've Made

In Topic: Bubble Glaze Experiment With Close Ups.

13 December 2014 - 07:52 AM

Outgassing of the frit? I don't think there are any volatile components in the frit    (SNIP)


Matt, it would be interesting to know the firing and cooling schedules....

I meant that the frit was probably the ingredient that was becoming liquid at the lowest temperature thus trapping the outgassing of other chemicals. I did not word it very clearly. Sorry.


It would be nice to know the firing schedules.

In Topic: Bubble Glaze Experiment With Close Ups.

12 December 2014 - 02:00 PM

Do we know what causes these bubbles?

It might prove helpful to be able to control this effect to one's liking.

I hypothesize that some parts of the glaze are becoming molten at a temperature below the temperature where the others are finished outgassing. Im thinking the frit.

Have you tried reformulating to eliminate the frit?

In Topic: Huge Pots

17 November 2014 - 09:07 AM

They make roof tiles in China with a similar internal mold method. Their mold is more like a roll top desk top with cloth and sticks but they've been doing it that way for a long time.

In Topic: Grinding Clay, Use A Hammer Mill?

17 November 2014 - 09:03 AM

I vote for the wet method and here's why, time.

get your 5 gal bucket and add 5~10 lbs of clay and will with water (5 minutes) then GO AWAY for a day

get your drill mounted paint mixer and stir the hell out of it (5 minutes) then GO AWAY for a couple of hours

carefully pour off the top layers into another bucket, straining through window screen if you want (5 minutes)You can add water back to the first bucket if you want and repeat the next steps, then GO AWAY for a day

pour the water off the second bucket then pour the slip into a goodwill pillow case (5 minutes) then go away til its ready


20 minutes work time for usable clay that is properly hydrated.


Keeps dust down too though I do this outside for that reason.



This is an excluding process. If there are things in the clay that you don't want and they are large particle or will settle this method will exclude them.

Some particles may be excluded that you don't want excluded fyi (mica etc) so be aware of that.


I have a local earthenware that is full of limestone and pops out pretty badly unless I use this method to get the limestone sand out.


have fun!

In Topic: Store Bought Clay Slip Is Way Too Thick...

13 November 2014 - 08:38 AM

You need to measure the specific gravity. Even if it was commercially made slip you need to be able to check to see of it was made right. Sometimes mistakes are made and checking things like SG can save you from using faulty materials and wasting a whole production cycle. The material supplier can readily replace faulty materials but may be less likely to compensate you for lost time and firing costs.

If the SG is correct and it is too thick then as mentioned it is either thixotropic and needs a good stir or it is under deflocculated (in which case the supplier messed up)

Check the SG.