Boraq 3

Description: Plainsman Plastic Gerstley Borate Substitute

Oxide	Analysis	Formula
CaO	27.30%	0.82
K2O	0.50%	0.01
MgO	2.00%	0.08
Na2O	3.20%	0.09
B2O3	26.50%	0.64
Al2O3	2.40%	0.04
SiO2	11.90%	0.33
Fe2O3	0.10%	-
LOI	26.05%	n/a
Oxide Weight		124.58
Formula Weight		168.47

Notes

Boraq 3 was recommended for cone six and above where high CaO was needed (e.g. for chrome tin reds and pinks and for glazes that rely a lot on the boron-blue effect, that is, a lot of calcium borate crystalization). Good examples of this type of glaze are transparents that have a lot of bluish-white cloulding that opacifies them. It was 84 Boraq 1 and 16 whiting.

It was developed under code number L3127I.

Related Information

Links

Materials	Boraq This Gerstley Borate substitute was available during the early 2000s. Its recipe and development are well documented but two materials are no longer available.
Materials	Boraq 2
Typecodes	Flux Source Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
URLs	https://insight-live.com/insight/share.php?z=eeukDwSTt4 The Development of a Gerstley Borate substitute - Boraq

By Tony Hansen
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