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Randy's Red Cone 5

Code: G2826X
Modification Date: 2015-10-30 17:50:16

A popular Gerstley Borate based iron-red glaze.

F-4 Feldspar19.816.9%
Gerstley Borate31.727.1%
Red Iron Oxide15.012.8%


There is much more information about this glaze at

The Boraq Gerstley Borate substitute works well in this recipe.

Iron Red glazes look a little different in a flow tester

Iron Red glazes look a little different in a flow tester

A GLFL test for melt flow comparing two cone 6 iron red glazes fired to and cooled quickly from cone 6. Iron reds have very fluid melts and depend on this to develop the iron red crystals that impart the color. Needless to say, they also have high LOI that generates bubbles during melting, these disrupt the flow here.

G2896 Ravenscrag Plum Red iron red cone 6 glaze

G2896 Ravenscrag Plum Red iron red cone 6 glaze

Original development of this recipe was done to match the chemistry of Randy's Red (a popular recipe). At the time we did not do any special firing schedule to encourage the growth of the red crystals.

Out Bound Links

In Bound Links

XML to Paste Into Insight

<?xml version="1.0"?>
<recipes version="1.0" encoding="UTF-8">
<recipe name="Randy's Red Cone 5" keywords="A popular Gerstley Borate based iron-red glaze." id="63" date="2015-10-30" codenum="G2826X">
<recipeline material="Silica" amount="29.700" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Kaolin" amount="5.000" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="F-4 Feldspar" amount="19.800" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Talc" amount="13.900" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Gerstley Borate" amount="31.700" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Red Iron Oxide" amount="15.000" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Bentonite" amount="2.000" unitabbr="kg" conversion="1.0000" added="0"/>
<url url="" descrip="Recipe page at"/>

By Tony Hansen

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