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How To Use Frits, Gerstley And Gillespie Borates For A Satin Finish


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#1 sandra b

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Posted 25 November 2010 - 01:10 PM

I made some tests by brushing 3110, 3124 and 3134. I used 1 tsp in a cup of water. The solution showed a lot of brush marks; and after firing at cone 5, it showed more sheen where it was more thickly applied. I made another test spraying frit 3124, it showed some sheen after firing at cone 5, but not the satiny finish I was hoping for.
Next test was spraying Gerstley/Gillespie borate solution using 1 tsp in about 3 cups of water. I fired again at cone 5, which is the lowest standard temperature for glazing at the community college where I fire my pieces. The result was a very dry harsh finish.
My intention is to find a finish that adds a slight flux to the stained and underglazes I use to finish my pieces, something that doesn't look neither too dry or too shiny. I can fire at other temps if I can gather enough work to fill a small kiln. I would appreciate some ideas in how to apply these or other materials to obtain that satiny, smooth finish that I dream of. Thanks and Happy Thanksgiving!

#2 Marcia Selsor

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Posted 26 November 2010 - 05:08 AM

Why don't you use a satin glaze for your base with a brush work additive like a cmc mix?
Are you brushing on top of a glaze?Are you simply trying to cover the underglazes for a finish only in certain areas?
Marcia

#3 sandra b

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Posted 27 November 2010 - 11:24 AM

Thanks, Marcia.
A while ago I made some tests with a satin glaze under and on top of stains and commercial underglazes. I liked it best with the color on top of the glaze . The finish was really nice, but some of the underglazes and stains peeled off. I have not tried it using a commercial glaze yet. It's on my list.
I like color and the depth you achieve by layering underglazes and the possibility of multiple firings, having a glaze somewhat limits the process. I read of a Gerstley Borate washes, frit finishes and/or mixing some fluxes to commercial underglazes, but with my tests I have not obtained good results so far. Any other ideas?

#4 Marcia Selsor

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Posted 27 November 2010 - 03:14 PM

I guess much depends on the clay. What are you using for a white base? White clay? White Slip? If your underglaze is peeling off , is that where the glaze was on top?
Reaaly not clear. Can you post a jpg in the gallery?
marcia

#5 Deb Evans

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Posted 06 December 2010 - 12:26 PM

If you go for a satin glaze and just want a surface - thin the stuff down a lot so that it just gives a white veil to the stains -



#6 sandra b

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Posted 11 December 2010 - 05:45 PM

Hi Marcia & Deb,

Thanks for your answers.

It took a while, but here are some of my tests.

Mid range red clay fired at cone 5. Left of tile shows 3 coats of Amaco underglazes over studio glaze, and right side shows them under.
Left tile has Paul's White (A), Middle has Satin White (A) and right has French White ©
1)Colors from top to bottom:
LUG 43: Dark Green, bubbled on A & B Left
LUG 21: Medium Blue, bubbled on A left
LUG 26: Turquoise
LUG 22: Dark Blue
LUG 1: Black
http://picasaweb.goo...562219560356242

2) Colors from top to bottom:
LUG 60: Light yellow, bubbled on A, B & C Left
LUG 65: Orange
LUG 61: Bright Yellow, bubbled on A & B Left
LUG 40: Chartreuse, bubbled on A & B Left
LUG 55: Purple
http://picasaweb.goo...562233424094338

3) Colors from top to bottom:
V 315: Peach, bubbled on B Left
V 382: Red
V 372: Mint Green: peeled off on A&B left
V 320: Lavender
V 380 Violet
http://picasaweb.goo...562235847313666

4) Colors from top to bottom:
V303: Terracotta, peeled off on A left
V 382 Red
V 381 Amethyst
V 370 Velour Black , bubbled on A, B & C at left
http://picasaweb.goo...562240135736850

5) Grey Stoneware, painted with underglazes and sprayed with frit 3124, fired to cone 5
http://picasaweb.goo...562275082881474

6) Grey Stoneware painted with underglazes and sprayed with Gerstley Borate, fired to cone 5
http://picasaweb.goo...562288754556370

#7 Marcia Selsor

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Posted 12 December 2010 - 07:35 AM

These look like you are getting what you were after. Great!
Good luck with getting the results on your larger pieces.
Marcia

#8 Deb Evans

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Posted 12 December 2010 - 01:11 PM

your experiments look great! remember that some glazes and stains react to red clay body, looks like it's more stable w/ the gray stoneware.
happy holidays.



#9 sandra b

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Posted 12 December 2010 - 08:52 PM

Thanks to both of you for the encouragement.
Happy Holidays:)




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