How to............... Line blend andBiaxial blend

Lineblends

If you make up one glaze, test it and you don't like the result, you have few clues as to what you should do to get a better result. If you blend together two different glazes, you immediately get a range of glaze tests and can clearly see the effect of one glaze on another. Sometimes the effects can be very interesting. This technique can be used to explore existing glazes you have, or to develop colour blends, to see the effect of increasing a particular ingredient on a glaze, or even blending stoneware and earthenware glazes to develop midfire glazes.

All you will need is a jug, small seive (120# or around that), disposable cups, marker pen and a 60ml syringe (these can be hard to find, but vets have them and may give/sell you one).

Mix up 100g of glaze A and 100g glaze B to the SAME VOLUME (use the jug). The volume will vary depending on the glaze, but should be around 200ml, with the glaze being the consistency of single cream. Make sure that you mark the cups with pen to avoid mistakes.

The lineblend can have as many intermediate glazes as you like between A and B. Here I will show a 7 glaze lineblend. The top line shows percentages, the bottom row shows syringe volumes.

Glaze 1

100%A 0%B

Glaze 2

83.3%A 16.7%B

Glaze 1

66.7%A 33.3%B

Glaze 1

50%A 50%B

Glaze 1

66.7%A 33.3%B

Glaze 1

16.7%A 83.3%B

Glaze 1

0%A 100%B
glaze A

50 mlA + 10ml B

 40 mlA + 20ml B 30 mlA + 30ml B 20 mlA + 40ml B 10 mlA + 50ml B glaze B

Mix the glazes thoroughly, then dip an angled test tile into each, or use the syringe to trail a patch of glaze onto a tile. Vertical standing test tiles are best as they show movement of the glaze (runny glazes) and how it might change on edges (eg tenmoku glazes). Make sure that you mark the test tiles with iron brushwork so you know which is which and apply the glaze thin and thick on the same (or seperate) test tiles. Many glazes vary considerably on the thickness of their application with crazing, colour, texture and fluidity.

Biaxial blends

These blends are slightly more complicated, involving the blending of 4 glazes at the corners of a square or rectangular grid. The reasons you would do a biaxial blend would be to get a much more detailed view of a certain glaze with only two variables (eg. the celadon biaxial gicen here, where alumina and silica levels are varied), or to get a broad range of colours from a couple of additions to a specific base glaze.

The celadon tests here are a biaxial blend. In this test the fluxes that make the glaze melt are remaining the same ratios, the amount of colourant (0.5% iron) is the same, but the amount of alumina and silica in the glaze is varied to give a broad range of glaze qualities.

To do this blend you will need 4 larger pots (A,B,C and D), 21 disposable cups, jug, seive and syringe. You will need to weigh out 400g of each of the corner glazes and make each up to the same volume using the jug.

I could give a figure of the entire grid, with the contents of each cup in percentages, but I think this only complicates the test. The easiest way to approach it is to think of a series of lineblends.

 

A

 

300ml A

100ml C

200ml A

200ml C

100ml A

300ml C

C

 

B

 

300ml B

100ml D

200ml B

200ml D

100ml B

300ml D

D

 

Lineblend the two edges of the grid ie. lineblend A and C giving glazes 1(A), 6,11,16 and 21(C). Then lineblend B and D, giving glazes 5(B), 10,15,20 and 20(D)

Dip marked test tiles into all of these glazes
 
Glaze 1 (A)
Glaze 6
Glaze 11
Glaze 16
Glaze 21(C)
Glaze 5 (B)
Glaze 10
Glaze 15
Glaze 20
Glaze 25(D)
90ml : 30ml
60ml : 60 ml
30ml : 90ml
90ml : 30ml
60ml : 60 ml
30ml : 90ml
90ml : 30ml
60ml : 60 ml
30ml : 90ml
90ml : 30ml
60ml : 60 ml
30ml : 90ml
90ml : 30ml
60ml : 60 ml
30ml : 90ml