All Glossary

Liner glazing

How to apply inside and outside glazes to a pottery mug and get them to meet at a clean line at the rim.

Key phrases linking here: liner glazing, liner glazed, liner-glazed - Learn more

Details

This is a technique of glazing pottery (as opposed to the choice of a safe glaze for the insides of functional pieces). Different glaze colors on the inside and outside meet in a clean line at the rim. The technique is common in commercial ware and requires precision to execute well.

• Use glazes that do not have too much melt fluidity (run too much during firing) or they may bleed into each other across the join.
• Use a thixotropic dipping glaze, don't put up with problems of excessive dripping, settling in the bucket, slow or drying.
• Form the mug (on the wheel) such that the lip flares out a little, this will reduce dripping down the outside on the outpour. Also round the lip so the glaze join line occurs on a rounded contour.

Step-by-Step

1. Fill the bisque mug with liner glaze. Pour it out in a circular motion and then dip the lip. Hold it there long enough to get the thickness needed:
2. After the glaze has dried sufficiently, use a banding wheel to wax up the inside (starting about an inch down) and just up around the top of the lip.
3. Using a sharp knife (e.g. Olfa cutter) in one hand and rotating the mug with the other, cut away the glaze (down to the bisque) up to the highest point on the lip (the best cut with the least dust is done when the glaze is still damp). Clean up any remaining glaze down around the outside of the rim using a fettling knife. Now the inside glaze terminates at a perfect wax-covered edge at the lip. It may be necessary to clean any remaining glaze off the outside up to the wax line using a damp sponge. This is important if the outside glaze is not going to be applied right away, otherwise the dried glaze residue will cause adherence problems.
4. Let the mug dry a while and glaze the outside (if it is thin-walled an extended drying time may be needed). Keep your hands damp so they will not stick to the wax (and pull off sections as you touch it). Push the lip of the mug into the glaze 5-10mm (be careful to hold the mug level as you do this). Immediately turn it over, put your hand inside and clamp against the interior surface and push it into the glaze right down to the rim (to overlap the lip dip just made). It may be tricky at first to push the mug down far enough and avoid glaze spilling inside.
5. Set the mug on a turntable to sponge away any drips left over the wax-covered liner on the inside top of the lip.
6. Clean the foot and set it out to dry.

Related Information

Liner Glazing a porcelain mug

The process of applying a liner glaze to a piece (by pouring), applying wax emulsion and terminating it at the rim, then immersing the outside of the piece into a dipping glaze to apply another color to the outside.

Wax emulsion enables liner glazing and much more

This technique enables the use of a liner glaze, in this case GA6-B. These are most valuable where the outer glaze is reactive (melt-mobile, crystallizing or heavily pigmented) and therefore potentially leachable. Not only are liner glazes less likely to leach but they are less likely to craze, this assures water tightness and eliminates any potential for bacteria growth in the cracks (especially if the body has porosity). Liner glazes are also less likely to stain and cutlery mark, adding to the durability of pieces. The straightness of the dividing line is affected by the degree to which the two glazes bleed into each other. Liner glazing also adds a decorative element to pieces. This technique is also practical where mug walls are thin and cannot absorb enough water to dry the glaze quickly after dipping or brushing.

Beautifully finished mugs from Tim Hortons

Notice they have a liner glaze. The outside decoration has been done using wax resist and transfer techniques.

Mistake when liner glazing a mug

The white inner liner glaze (that wraps over the rim) was not removed after the wax was applied. The outer glaze thus overlays patches of it near the rim. The meeting line has been blurred and the other glaze has run downward and crawled somewhat revealing patches of the inner one.

Which liner glazing looks better to you?

With the proper technique of applying a liner glaze you can make the outside and inside ones meet in a straight line at the rim rather than just have one spill over the other.

A fluid melt glaze bleeds much more into adjoining ones

The outer green glaze on these cone 6 porcelain mugs has a high melt fluidity. The liner glaze on the lower one, G2926B, is high gloss but not highly melt fluid. Notice that it forms a fairly crisp boundary with the outer glaze at the lip of the mug. The upper liner is G3806C, a fluid melt high gloss clear. The outer and inner glazes bleed together completely forming a very fuzzy boundary.

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