whitehart_designs: porcelain (Default)
Still searching for a yellow glaze recipe. It has to be compatible with cone 10 reduction firing and and be relatively non toxic.I think I have been through every database on the internet looking. I even found a glaze that claims to be very similar to Otto Heino's, lol! I am not a chemist, so reading the technical books on glaze chemistry has been hard  for me and of course you read about one topic or definition, giving you hints and nuggets of information and it leads you to connect the dots.
Things that  i have found in sources  that  say will contribute to making a true iron yellow.
An alkaline base such as Custer feldspar
A Calcium-magnesium additive such as dolomite.
Zircopax to brighten the iron colour
Epk to add more silica, a trace of iron
Possibly a little more silica (flint) to make  it less dry.
3.5%  red iron oxide
I done 3 other tests so far and the have turned out a  either a muddy yellow greenish runny mess , or a dark dried mustard looking thing with black bits where its thick.

The glaze i have had best results so far is the yellow salt .
Nephline syenite   63.9
Dolomite                 21.1
Zirconia (zircopax) 16.
ballclay (om4)        4.2
Add Bentonite 2% and Red iron oxide 1.%

It has the Calcium-magnesium thing going ,And the zirconia content.( Zircopax)
Although it has a great butter colour when thick, thin it is a musard colour. :(
also too shiny. I want a satin finish.
Makes me wonder if i should change to  ball clay to EPK  and to and neph sye to custer just to see what happens.
I think i'll run it through my glaze program to  check the oxides.
I suppose we could do oxidation firings i can't find the perfect reduction yellow.
Not giving up yet, though.

The new studio has a a garage door on it now. It was installed this morning.  The  walls have been taped an the first layer of plaster has been sanded .Waiting for the drywall workers to come back and finish, so we can paint. D also cut back all the vegetation away from our house so it can be painted the same colour as the studio.

School; Well glaze class is zipping along. I need to get more 500 gram bach containers, probably will wind up recycling the ugly yellow glaze results. As for pottery, I have been focused on making some larger pieces than i have been accustomed to.  Discovering some engineering tricks , and  been inspired by the larger area to paint  or carve.  Been turning out about 3 large bowls, and pedestal  plates a week . My most favorite bowl  stuck to the shelf last week an it damaged the feet. I have to pour the glaze over sections of the bowls so i managed t get too much glaze around the feet leading to stuck feet on the shelf. Have to scrape around the foot creases to rid it of surplus glaze in the future!
I have had fun with the Afgani wood textile  blocks making impressions in the clay slabs, glad i bought them. :) Thinking of buying anothe batch. The pieces i have made turned out absolutely stunning, I surprised myself!  some of the blocks i have are like new, the fellow who sold them to me said  some of the blocks are 50 to 100 years old. They are made of a super hard wood and blackend with age, use, and dyes.


whitehart_designs: porcelain (Default)

May 2017

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