Clear Glaze Application

[Katie S]

I’m still new to the ceramics process, I only started throwing early this year and am finally starting to work on glazing. One thing I’m uncertain on is clear glaze (brush) application.

How many coats do I need to do if I’m applying clear directly to bisqueware? 

If applying on top of other colored glazes, do I need to do multiple coats?

Thank you all for helping me learn!

[Callie Beller Diesel]

The maddening answer to just about everything in glazing is “it depends.”

IF it’s available to you, clear glazes are usually much easier to apply thinly and evenly via dipping. If it’s not, then brush away. 

If you’re mixing 2 glazes, this can often result in special effects that are partially due to running. When starting out you might only want to apply 3 layers in total, however you want to divide it out. Usually you don’t need a clear glaze over other glazes, unless you’re hoping it’ll do something interesting. If that is what you’re going for, make sure you have a waster or a cookie under your piece to catch any drips. Cleaning kiln shelves is not fun!

 Learning how to apply glaze is another skill that takes experimentation and practice to get the hang of, and it’s a good idea to do some test tiles before you start glazing your favourite piece. Recommendations on the label should be considered starting points. Your idea of a thick coat and someone else’s might not be the same thing, and you have to play around with it a bit to find your sweet spot. 

Generally clear glazes want a thinner application than other things for best results. An overly thick clear glaze will go a bit cloudy. This effect is more noticeable on dark clay or underglazes than it is on lighter coloured things. 

 

[Chilly]

On 9/8/2023 at 3:00 AM, Katie S said:

How many coats do I need to do if I’m applying clear directly to bisqueware? 

It depends.....  Some people are heavier appliers than others.  Commercial glaze usually says apply 3 coats.  I have seen people apply three coats that look like my 1 coat, and others whose 3 coats would puddle all over the kiln shelf.

At our community centre, I get newbies to do a "number of coats" test tile, before they do any glazing or underglazing.  A square tile of clay, marked into 4 smaller squares.  Corner 1 gets one coat of underglaze, corner 2 gets 2 coats, corner 3............etc

This gets bisque fired and then they apply 1 coat of clear on half of corner 1, 2 coats on half of corner 2..........

Second fire to earthenware, (we don't do any high-fire) then they (I) can determine if they are a light applier or a heavy applier.  This gives them a guide for future applications.    

We often repeat with a vertical tile with texture.

Edited September 10, 2023 by Chilly

[neilestrick]

There's no reason to apply a clear glaze over a colored glaze unless you like how it alters the look of the colored glaze, and it will alter the look of the colored glaze, sometimes just a bit, but often quite a lot. The clear will not just sit on top of the colored glaze. Whenever you layer glazes, they mix and mingle, and often become runnier. To what degree all that happens depends entirely on the formula of the glazes, the thickness of the application of each glaze, and the order in which they are applied. Test, test, test.

[oldlady]

katie, are you using bottled glazes exclusively?   i have found that a number of the potters in my guild use only bottled glaze and it behaves differently than anything made by a potter for individual use.   there is a website for cone 6 users of bottled glaze but i do not know its name.