May 2026: We are continuing a major code rewrite. Please contact us if you find issues. Thank you.

BORY1 - Bory 1 Crystalline Glaze
CELECG - Celestite Crystalline Glaze
FAAO - Fa's All-Opaque Crystalline Glaze
FAC5 - Crystal Number Five Glaze
FO - Octal Crystalline Glaze
G1214M - 20x5 Cone 6 Base Glossy Glaze
G1214W - Cone 6 Transparent Base
G1214Z1 - Cone 6 Silky CaO matte base glaze
G1215U - Low Expansion Glossy Clear Cone 6
G1216L - Transparent for Cone 6 Porcelains
G1216M - Cone 6 Ultraclear Glaze for Porcelains
G1916Q - Low Fire Highly-Expansion-Adjustable Transparent
G1947U - Cone 10 Glossy transparent glaze
G2000 - LA Matte Cone 6 Matte White
G2240 - Cone 10R Classic Spodumene Matte
G2571A - Cone 10 Silky Dolomite Matte glaze
G2826R - Floating Blue Cone 5-6 Original Glaze Recipe
G2826X - Randy's Red Cone 5
g2851H - Ravenscrag Cone 6 High Calcium Matte Blue
G2853B - Cone 04 Clear Ravenscrag School Glaze
G2896 - Ravenscrag Plum Red Cone 6
G2902B - Cone 6 Crystal Glaze
G2902D - Cone 6 Crystalline Development Project
G2916F - Cone 6 Stoneware/Whiteware transparent glaze
G2926B - Cone 6 Whiteware/Porcelain transparent glaze
G2926J - Low Expansion G2926B
G2928C - Ravenscrag Silky Matte for Cone 6
G2931H - Ulexite High Expansion Zero3 Clear Glaze
G2931K - Low Fire Fritted Zero3 Transparent Glaze
G2931L - Low Expansion Low-Fire Clear
G2934 - Matte Glaze Base for Cone 6
G2934Y - Cone 6 Magnesia Matte Low LOI Version
G3806C - Cone 6 Clear Fluid-Melt transparent glaze
G3838A - Low Expansion Transparent for P300 Porcelain
G3879 - Cone 04 Transparent Low-Expansion transparent glaze
GA10-A - Alberta Slip Base Cone 10R
GA10-B - Alberta Slip Tenmoku Cone 10R
GA10-D - Alberta Slip Black Cone 10R
GA10x-A - Alberta Slip Base for cone 10 oxidation
GA6-A - Alberta Slip Cone 6 transparent honey glaze
GA6-B - Alberta Slip Cone 6 transparent honey glaze
GA6-C - Alberta Slip Floating Blue Cone 6
GA6-D - Alberta Slip Glossy Brown Cone 6
GA6-F - Alberta Slip Cone 6 Oatmeal
GA6-G - Alberta Slip Lithium Brown Cone 6
GA6-G1 - Alberta Slip Lithium Brown Cone 6 Low Expansion
GA6-H - Alberta Slip Cone 6 Black
GBCG - Generic Base Crystalline Glaze
GC106 - GC106 Base Crystalline Glaze
GR10-A - Pure Ravenscrag Slip
GR10-B - Ravenscrag Cone 10R Gloss Base
GR10-C - Ravenscrag Cone 10R Silky Talc Matte
GR10-E - Alberta Slip:Ravenscrag Cone 10R Celadon
GR10-G - Ravenscrag Cone 10 Oxidation Variegated White
GR10-J - Ravenscrag Cone 10R Dolomite Matte
GR10-J1 - Ravenscrag Cone 10R Bamboo Matte
GR10-K1 - Ravenscrag Cone 10R Tenmoku
GR10-L - Ravenscrag Iron Crystal
GR6-A - Ravenscrag Cone 6 Clear Glossy Base
GR6-B - Ravenscrag Cone 6 Variegated Light Glossy Blue
GR6-C - Ravenscrag Cone 6 White Glossy
GR6-D - Ravenscrag Cone 6 Glossy Black
GR6-E - Ravenscrag Cone 6 Raspberry Glossy
GR6-H - Ravenscrag Cone 6 Oatmeal Matte
GR6-L - Ravenscrag Cone 6 Transparent Burgundy
GR6-M - Ravenscrag Cone 6 Floating Blue
GR6-N - Ravenscrag Alberta Brilliant Cone 6 Celadon
GRNTCG - GRANITE Crystalline Glaze
L2000 - 25 Porcelain
L3341B - Alberta Slip Iron Crystal Cone 10R
L3685U - Cone 03 White Engobe Recipe
L3724F - Cone 03 Terra Cotta Stoneware
L3924C - Zero3 Porcelain Experimental
L3954B - Cone 6 Engobe (for M340)
L3954N - Cone 10R Base White Engobe Recipe for stonewares
MGBase1 - High Calcium Semimatte 1 (Mastering Glazes)
MGBase2 - High Calcium Semimatte 2 (Mastering Glazes)
MGBase3 - General Purpose Glossy Base 1 (Mastering Glazes)
MGBase4 - Glossy Base 2 Cone 6 (Mastering Glazes)
MGBase5 - Glossy Clear Liner Cone 6 (Mastering Glazes)
MGBase6 - Zinc Semimatte Glossy Base Cone 6
MGBase7 - Raspberry Cone 6 (Mastering Glazes)
MGBase8 - Waxwing Brown Cone 6 (Mastering Glazes)
MGBase9 - Waterfall Brown Cone 6 (Mastering Glazes)
TNF2CG - Tin Foil II Crystalline Glaze
VESUCG - Vesuvius Crystalline Glaze

Insight-Live Shares


77C04E - 50:30:20 Frit 3134 cone 6 base
77E05B - Cone 10R Celadon - Luke Lindoe
77E06B - Lindoe Dark Celadon - Lower COE
77E14A - Cone 10R Red Mustard - Luke Lindoe
77E15A - Cone 10R Yellow Mustard - Luke Lindoe
84-G-05-S - Cone 10R Matte Crystal Iron - Luke Lindoe
G 304 - Cone 10R Crystal Iron Brown - Luke Lindoe
G1002 - LEACH'S CELADON CONE 10R
G1129 - MEDALTA CLEAR GLAZE CONE 8-10
G1214M - Hansen 20x5 Clear Cone 6 Base Glaze
G1214Z - Cone 6 Calcium Matte Base Glaze
G1214Z1 - Cone 6 Calcium Matte v2
G1214Z2 - Cone 6 Calcium Matte + TiO2
G1847 - Cone 10R Robin's Egg Blue
G1916M - COE Adjustable Low Fire Clear Glaze
G1916Q - Cone 05+ Expansion Adjustable Gloss Base
G1916Q2 - G1916Q glaze + 5% silica
G1916Q3 - G1916Q glaze + 10% silica
G1916QL - Cone 05+ Low Expansion Transparent glaze
G1916QL1 - Cone 05+ Lower Expansion glaze
G1916S - Cone 06-04 MgO Matte
G1916S1 - Cone 06-04 MgO (using talc)
G1916V - Cone 2 Clear (based on G1916Q)
G1916W - G1916Q with Iron Fining Agent
G1947U - Cone 10/10R Transparent Base
G2415E - Classic Albany Lithium Brown Glossy
G2415J - G2415E Alberta Slip Brown (less Li)
G2571A - Original Cone 10R Silky Matte Base Recipe
G2571B - Cone 10R Silky Matte Base (improved)
G2571BB - G2571B Rutile Bamboo
G2571C - Cone 10R Silky Matte Blue
G2571D - Cone 10R Silky Matte Red
G2571D1 - Cone 10 Marbled Red Glaze
G2571E - Cone 10R Silky Matte Black
G2576B - Cone 10R Tenmoku Glossy
G2584 - Cone 10R Blue Celadon
G2826A - 50:30:20 Gerstley Borate Cone 6 base
G2826A1 - 50:30:20 Frit 3134 base (fixed)
G2826A2 - 50:30:20 Gillespie Borate Cone 6 base
G2826A3 - 50:30:20 GB Makeover Pottery Glaze
G2826B - GB:Frit Raku Glaze
G2826F - GB Honey Amber 04
G2826G - GB Lavendar Satin Glaze Cone 6
G2826M - Gerstley Borate Antique Green Cone 5
G2826N - Gerstley Borate Raku Base NS/GB
G2826R - Floating Blue Original Cone 6 Glaze
G2826R1 - Floating Blue Using Gillespie Borate
G2826U - Floating Blue using Frit 3134
G2826V - Gerstley Borate Cream Oatmeal Cone 6 recipe
G2850C - Ravenscrag Cone 6 Black Glossy
G2850M-C - Ravenscrag Cone 6 Light Blue Matte
G2850P - TEAL BLUE CONE 6 KAT
G2851A - RAVENSCRAG SLIP Matte Blue - Cone 6
G2851AB - RAVENS FLOATING BLUE Cone 6
G2851D - KAT'S RC MATTE - Cone 6
G2851H - RAVENSCRAG Brown Gold Matte Cone 6
G2880 - Alberta Slip Tenmoku #1
G2880A - Alberta Slip Tenmoku #2
G2881B - Ravenscrag Alberta Slip Celadon
G2890B - Randy's Red Original Cone 6 Glaze
G2894 - Ravenscrag Tenmoku #1
G2894A - Ravenscrag Tenmoku #2
G2908A - Alberta Slip Floating Blue
G2917 - Ravenscrag Floating Blue
G2926 - Perkins Clear
G2926A - Perkins Clear with Frit 3134
G2926B - Cone 6 Clear Glossy Base
G2926BL - G2926B Cone 6 Gloss Black
G2926J - G2926B Reduced COE (Li2O)
G2926S - G2926B Reduced COE (MgO)
G2931 - Worthington Cone 06-2 Clear
G2931F - Zero3 Ulexite Transparent Glaze
G2931G - Zero3 G Low Expansion Low Fire Clear
G2931H - Zero3 H High Expansion Variant
G2931K - Zero3 K Cone 03 Transparent Glaze
G2931L - Zero3 L Low Expansion Variant
G2931L2 - Zero3 L Low Expansion w/F-69
G2932 - Deb's Clear #1 Cone 04-02
G2932A - Deb's Clear #2
G2933 - Gerstley:PV Clay low fire clear
G2934 - Cone 6 Magnesia Matte Base
G2934A - High Dolomite-Testing glaze
G2934BL - G2934 85:15 Adjustable Matte Black
G2934J - G2934 with ZnO for Brown Stains
G2934J1 - G2934 (glossed using ZnO)
G2934Y - G2934 (lower-LOI)
G2934Y1 - G2934Y (Anti-Crawling)
G2934Y2 - G2934Y (Higher COE/Stony)
G2934Y3 - G2934 Super Durable
G2934Y4 - G2934 Super Durable #2
G2934Z - G2934Y Red Using F-69
G2936 - Ravenscrag Low Expansion Cone 6 Base
G2936B - Ravenscrag Low Expansion White Base 2
G2936C - Ravenscrag Original Cone 6 Base Glaze
G2938 - Wright's Water Blue Base
G2941A - Leach's Satin Clear Original
G2941C - Leach's Satin Clear - Craze fix
G3806 - Panama Blue Cone 6
G3806A - Panama Blue 2 - More clay, Copper Oxide
G3806B - Panama Blue 3 - Copper Carbonate
G3806C - Panama Cone 6 Adjustment 2015
G3806D - Panama c6 - Lower COE #1
G3806E - Panama c6 - Lower COE #2
G3806F - Panama c6 - Lower COE #3
G3806K - Panama c6 - Lower COE #7
G3806N - C6 Fluid Clear Final Recipe #10
G3808 - Cone 6 Bright Clear - Shaun Mollonga
G3808A - Cone 6 Bright Clear using Frits
G3813 - Campana Cone 6 Transparent Glaze
G3813B - Campana Clear Lower Expansion #2
G3813C - Campana Clear Low Expansion (no Spodumene)
G3814 - Low Zinc High Feldspar Fritless base
G3822 - Spectrum Clear 700 Dipping Glaze
G3834 - Tenmoku Cone 6
G3840 - Shino Trial Number 1
G3868 - Gold - Cone 6
G3868A - Gold Using Spodumene
G3868B - Gold Using Fusion Frit 493
G3868C - Gold Using Frit #2
G3875 - Tangerine 4 (Orange)
G3875B - Zinc Clear cone 6
G3875C - Tangerine + Orange Stain
G3879 - Cone 04+ UltraClear Glossy Base
G3879C - Cone 04 UltraClear Low-Expansion
G3879E - Cone 04+ UltraClear Glossy Base
G3879F1 - Cone 04+ UltraClear Glossy Base
G3888 - Kieth Davitt High-fluid-melt copper blue
G3892 - Val Cushing Satin White #71
G3903 - Alberta Slip + Frit FZ-16
G3904 - Original Recipe Using Frit 3124
G3904A - 3134 Mistake Recipe Fixed
G3909 - Ravenscrag Cone 10R Matte Blue
G3910 - Fritted version of G1947U #1
G3910A - Fritted version of G1947U #2
G3912A - Surface Tension White Tin
G3914A - Alberta Slip Gloss Black
G3918 - Red Mustard in G2571A Base #1
G3925 - Perfect Clear
G3925B - Perfect Clear Make-Over #1
G3926B - G2926B with Tin/Zircopax
G3926C - G2934 White Tin/Zircopax
G3933 - G2934:G2926B Oatmeal - Cone 6
G3933A - G2934:G2926B Oatmeal Cone 6
G3933E - G3933 Oatmeal Ravenscrag #2
G3933EF - G3933 Oatmeal Ravenscrag #4
G3933G1 - G3933 Oatmeal Alberta Slip + Li
G3939A - Cone 6 Oxidation Marbled Red
G3948 - Red Orange Glazy Original
G3948A - Plainsman Iron Red Orange
G3948A1 - Red Orange - Plainsman Spodumene
G3948A3 - Red Orange - Plainsman Spodumene #2
G3955 - N505 Base Satin White - Opaque
G3966 - Cone 10R S2 - Luke Lindoe
G3971 - Lead Bisilicate Glaze
G3973 - Hilda Ross Rust
G4546 - Pattis Crystal Clear Cone 6
G4594 - 3B as a glaze
GA6-A - Oringal Alberta Slip Amber/Honey base
GA6-F - Alberta Slip Cone 6 Oatmeal
GR10-A - Ravenscrag Cone 10R Transparent Base
GR10-C - Ravenscrag Talc Matte
GR10-CW - Ravenscrag Cone 10R Talc Matte White
GR6-H - Ravenscrag Cone 6 Oatmeal
H0009 - 1945 MEDALTA FILTER CAKE
L2553B - Imco Carbondale Clay - C-Red
L2596E - H550 Casting Body #5
L2596F - H550 Casting Body #6
L2596G - H550 Casting Body #8
L2626 - Barnard Slip
L3127E - Boraq 1
L3127G - Boraq 2
L3127I - Boraq 3
L3127N - Boraq 5 #4 (available materials)
L3146A - Foundry Hill Creme+Nepheline
L3146B - New Foundry Hill Creme
L3146C - FHC + Kyanite
L3146D - FHC + Pyrax
L3164A - Cordierite Flameware - more bentonite, added grog
L3500 - Alberta Slip Original cone 6 base glaze
L3500G - Alberta Slip + Frit 3249
L3500H - Alberta Slip + Frit 3249 and Silica
L3523 - Cone 04 Gerstley Borate matte base
L3523A - Compare Boraq 5 #1 with GB in a glaze
L3523B - L3523 glaze using Boraq 5 L3127L
L3523C - L3523 glaze using Boraq 5 L3127M
L3523D - L3523 recipe using Boraq 5 L3127N
L3617 - Cornwall Stone substitute #2
L3619 - Cornwall Stone Average Analysis
L3660C - Flameware - Very High Pyrax with Molochite
L3660G - Pyrax/Kaolin Flameware
L3660P - Pyrax Flameware (low fire)
L3664A - PV CLAY Feb 2013 Shipment
L3673 - Laguna Barnard Slip Sub
L3685U1 - Zero3 Engobe Recipe
L3685Y - Cone 03 Terrastone 2 Engobe
L3685Z2 - Z2 White Cone 04 Engobe Base (no frit)
L3685Z3 - Z3 White Cone 04 Engobe (5% frit)
L3685Z5 - White Cone 04 Engobe for L4170B (3% frit)
L3685Z6 - Brown Engobe for Snow
L3685Z7 - Cone 04 Brown Engobe for Snow
L3685Z8 - White Cone 2 Engobe for L215, L210, L4170B (2% frit)
L3693E - Alumina Lining for Crucibles
L3693E1 - Zircon Lining for Crucibles
L3693H1 - Plastic Refractory Alumina Body H1
L3724M1 - Redart Fritware #4
L3724M2 - Redart Fritware #5
L3724N - Redart Fritware #1
L3724N2 - Zero3 Stoneware
L3724P - Redart Fritware #2
L3728 - Cone 6 Dolomite Testing Glaze
L3778D - Cone 6 Translucent Grolleg Plastic
L3778D1 - Cone 6 Grolleg Pink/Blue Porcelains
L3778G - Cone 6 Translucent Grolleg Casting
L3798C - M340 Casting Body
L3798G - M340C Casting Body Revision 7
L3802E - Crystal Ice - Cone 10
L3806L - Panama c6 - Lower COE #8
L3840 - Diatomaceous Earth (Ant Killer)
L3868 - Craft Crank - From PotClays, UK
L3868A - Craft Crank - Base
L3868C - Craft Crank Clone 2
L3869 - Crank Industrial - From England
L3869A - Industrial Crank Base
L3894D - PV Calc Mix 4
L3906 - P300 Cone 6 Casting Body
L3911 - Bizen Clay
L3916 - Bizen Duplicate using Plainsman Materials
L3924C - Zero3 Porcelain - Experimental
L3924J - Zero4 Plastic Porcelain
L3924L - Zero4 Casting Porcelain
L3954B - Cone 6 White Engobe Recipe
L3954F - Cone 6 Black Engobe
L3954J - Black Cone 10 Whiteware Engobe Recipe
L3954N - Cone 10 Engobe for H550
L3954R - Super-White Engobe for Cone 6
L3954S2 - White Engobe for M340, M390, L215, L210
L3972 - 98 Mix
L3977 - BGP Low Stoneware Body
L4001 - Plainsman Super Kiln Wash
L4005D - M390 Casting Version 5
L4023F - Proposed H440 Casting Body #5
L4028 - G2571A Rutile Bamboo
L4053B - Cone 6 Black Clay Body - Type 1
L4068 - Barnard Chemical Substitute
L4115J3 - L211 Stnwre 3D:OM4:NS
L4115L2 - L211 3D:OM4:NS:Talc 42 mesh
L4115L2a - L211 3D:OM4:NS:Talc 80 mesh
L4158 - Cimtalc 15 Talc lab test
L4159 - Cimtuff 9115 Talc lab test
L4163 - Red Art Cone 1 Clay Body
L4168G5 - H440C (concentrate) #5
L4168G9 - New H440 Functional Proposal #8
L4170 - L215 Terra Cotta Casting #1
L4170B - Terra Cotta Casting #2
L4170F - Terra Cotta Casting #3
L4208C - MNS Cone 6 Fine Stoneware
L4208D - 3B +200# particles sieved out
L4217G - M370-like Cone 6 Faster Casting
L4227 - Plus Clay
L4228 - Fimo Clay
L4237 - Redart Tile Body
L4239 - H550 Casting Body #7
L4244 - BGP Clay:Flyash F 50:50 Mix
L4244A - Flyash F:Bentonite 10:90
L4245 - LaFarge Fly Ash F:Bentonite 95:5 Mix
L4245F - Fly Ash F:Bentonite:BallClay 80:10:10
L4246 - A2 +200# particles sieved out
L4247 - A3 +200# particles sieved out
L4248 - Old Hickory M23 Ball Clay
L4249 - 3D +200# particles sieved out
L4249A - 3D MNS 325 Mesh
L4249B - 3D 100 mesh
L4264 - Raku Crackle Glaze Base - Frit 3110
L4264A - Raku Glaze Base #1
L4264B - Raku Glaze Base #2
L4264C - Raku Glaze Base #3
L4264D - Raku Glaze Base #4
L4273 - G3806N1 + 2% Zircopax
L4280 - L215 : M390 Mix for Cone 1 Stoneware
L4287 - Midfield Clay Yukon
L4287A - Catchment Clay Yukon
L4292 - Monte Marte Air Hardening Clay
L4293 - DAS Air Drying Clay
L4294 - Sculpey PE08 Oven Bake Clay
L4398 - Ravenscrag Cone 6 Raspberry
L4404A - Refractory Casting Slip
L4404B - Plastic Refractory (heavy duty)
L4404C - Refractory Plastic (low expansion)
L4404D - Refractory Casting (low expansion)
L4410L - L213 NS:Dolo 30:20
L4410P - L213 40:10 Dolo/NS
L4421 - Seed pelleting clay and binder
L4441A - Minspar
L4441B - Minspar Calculated Substitute
L4453C - 3D:A2 Body Base H550 Blend
L4458 - Lithium Flameware Test
L4482B - Alumina Wadding #2
L4484D - 2018 3B+6% 6666 at 100#
L4498 - Low Expansion Super White Cone 6 Fritware
L4498A - Low Expansion Fritware Casting
L4530 - Carbondale M390 #1
L4530A - Carbondale M390 #2
L4532A - Pyrometric cone pressing body #2
L4532B - Cone pressing body #3
L4532D - Cone pressing body #5
L4532F - Cone 5 Cone-casting v.1
L4543 - Firebrick & kiln post/shelf clay - v1.0
L4543B - Firebrick & kiln post clay v2.0
L4543C - Refractory kiln post clay v4.0
L4557 - Volumetric Screw Feeder Design - ESP32 based
L4558 - M390 Casting (M370+C-Red)
L4558A - M390 Cone 6 C-Red Casting #1
L4558B - M390 Cone 6 C-Red Casting #2
L4567 - Cat Litter
L4575 - SIAL Refractory Slip
L4575A - SIAL refractory slip Duplicate
L4588 - Red NZK Cone 6 Porcelain
L4597 - Luke Lindoe Fired Samples
L4599 - Slip for Slipware
L4599A - Slip for Slipware - #5 Ball Clay
L4608 - Kyanite Bisque-Fix, Kiln-Patch
L4655 - Titanium Dioxide in GA6-C
L4655A - GA6-C Titanium + Iron
L4655B - GA6-C Lower Thermal Expansion
L4696 - Cordierite Flameware
L4697 - Flameware body from French mfgr
L4705A - GA6-C Using Frit 3195 and Titanium
L4768D - Cone 6 Black Casting Body - Type 2
L4768E - Cone 6 Black Casting Body - Type 3.1
L4768H - Cone 6 Black Casting Body - Type 3.3
L4807 - M370-like Super-Fast Casting Porcelain
MHSCUL - MASTER RedArt Sculpture Clay
MRG6B - G2850A Ravenscrag Cone 6 Light Blue
MRG6C - Ravenscrag Cone 6 White Glossy
MRG6E - G2850P Ravenscrag Cone 6 Raspberry
MRG6G - G2851H Ravenscrag Cone 6 Light Blue Matte
P4738A - 98 BGP RETEST
P4808 - 45D
P5867 - Sculpture Clay
P6385 - M2 ST
P6821 - L215 Production Run - Mar 2020
P7088 - H440
PC-32 - Amaco Glaze: PC-32 Albany Brown

L3685U - Cone 03 White Engobe Recipe

Modified: 2021-02-01 16:00:27

A white burning body with enough added frit to produce a cone 03 stoneware or white slip for use on the matching red Zero3 stoneware.

Material Amount Percent
Nepheline Syenite10.009.8
Tile #6 Kaolin42.0041.2
Ferro Frit 311025.0024.5
Silica20.0019.6
National Standard Bentonite5.004.9
102.00 100

Notes

This is both a slip (engobe) and body recipe. It is part of a development project during 2014 (spanning mixes from L3685A to T) to create a low fire stoneware system of body, slip (this) and glaze, dubbed Zero3. This slip matches the firing shrinkage of that body (but not of standard less vitreous terracottas).

This project started life as the popular Fish Sauce slip. That recipe has an unbelievable 10% bentonite. I questioned the logic of that much of a high-iron dirty cheap raw bentonite in a recipe containing low-iron low-plastic expensive Grolleg kaolin. I switched to highly plastic 6Tile kaolin and halved the bentonite, this gives as good or better whiteness. Of course this could fire whiter if Grolleg was used and plasticized with VeeGum or Bentone, but the amount of the latter needed would double or triple the cost of the recipe. The amount of whatever bentonite is used can be tuned to match the drying shrinkage of the body (using bi-clay strips).

This recipe is also plastic for throwing as a body, but it needs a little more bentonite (for better trimming). In a later version of this recipe, U1, we increased the bentonite to 5%.

Because at cone 03 feldspar is a filler rather than a flux, I traded it for the amount of frit required to get the degree of vitrification needed to match the firing shrinkage of the body. The frit is active, it basically is the glue that holds the fired matrix together, that glues the slip to the body. This works much better than frits in common use.

The silica is here to make it easier to fit glazes and to match the thermal expansion of terra cotta bodies (on which this can be used as a slip).

The frit also amplifies the color of any stains added, that means you can make colored slips from this same recipe, apply them at the leather hard stage and finish with a clear coat of glaze (start with 10:90 mix of stain and this recipe, some stains will need more, some less). This creates the possibility of single fire low temperature stoneware for brush-on glazes (although you will likely want to bisque before glazing for dipping the clear).

To use this as a slip, gel the slurry so that it will hang on and stay put after dipping ware into it.

Related Information

Here is why you don't want an engobe to melt


An over mature engobe is not opaque

This picture has its own page with more detail, click here to see it.

Too much frit in an engobe and it will lose opacity and whiteness. The white slip on the left is an adjustment to the popular "Fish Sauce" slip recipe (L3685A: 8% Frit 3110 replaces 8% Pyrax to make it harder and fire-bond to the body better). The one on the right, L3685C, has 15% frit. Although applied at the same thickness, it is becoming translucent, moving it into glaze territory. That means it will have a far higher firing shrinkage than the body (a common cause of shivering at lips and contour changes). This slip is basically a very plastic white body. Since white burning slips are made from refractory materials they are not nearly as vitreous as red ones, at low fire they need help to mature and a frit is the natural answer. With the right amount of frit the fired shrinkage of body and slip can be matched and the slip will be opaque. This underscores the need to tune the maturity of an engobe to the body and temperature. Although zircon could be added to the one on the right to opacify and whiten it, that would not fix the mismatch in fired shrinkage between it and the body. And it would increase the price.

One small pinhole in a terra cotta mug and we have a problem


This picture has its own page with more detail, click here to see it.

This is L3724E terra cotta stoneware. The inside slip is L3685S, a frit-fluxed engobe that is hard like the body and attaches well to it (engobes are often insufficiently fluxed). The glaze (G1916Q) is Frit 3195, Frit 3110 and 15% ball clay. The body has about 3% porosity, enough to make very strong pots. However that porosity is still enough to absorb water (and coffee). Although not too visible here, the pinhole in the inner surface has enabled absorption and there is a quarter-sized area of discoloration below the glaze. The piece could possibly be fired a cone higher, but testing would be required to see if the slip is still firing-shrinkage and thermal-expansion compatible with the body and that the body would not be over-fired. A better solution is adjust the firing curve to heal the glaze better. High temperature stoneware can easily have a 3% porosity also, so this is not just a low fire issue.

A vitreous terra cotta slip over a white low fire stoneware


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L3724F fluxed terra cotta slip applied over a white burning stoneware (L3685R) fired at cone 03. Most slips in use are not adequately fluxed and do not adhere well to the body below. The frit in this one attaches much better and even enables it to develop a sheen. Also, because of its volatility of color in the cone 03 range, variations in the shade and degree of sheen will impart an appearance like flashing.

Double-slip layer incised decoration: A challenge in slip-body fitting


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An example of a white engobe (L3685T) applied over a red clay body (L3724F), then a red engobe (also L3724F) applied over the white. The incised design reveals the white inter-layer. This is a tricky procedure, you have to make sure the two slips are well fitted to the body (and each other), having a compatible drying shrinkage, firing shrinkage, thermal expansion and quartz inversion behavior. This is much more complex that for glazes, they have no firing shrinkage and drying shrinkage only needs to be low enough for bisque application. Glazes also do not have quartz inversion issues.

L3685T-based engobes with 5% Mason stains added


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Each has been over-glazed using 1916J transparent and fired at cone 03. Micro-bubbles in the glaze is a problem.

What does it take to get a crystal-clear low fire transparent? A lot!


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These three cups are glazed with G1916S at cone 03. The glaze is the most crystal clear achieved so far because it contains almost no gas producing materials (not even raw kaolin). It contains Ferro frits 3195 and 3110 plus 11 calcined kaolin and 3 VeeGum. Left is a low fire stoneware (L3685T), center is Plainsman L212 and right a vitreous terra cotta (L3724F). It is almost crystal clear, it has few bubbles compared to the kaolin-suspended version. These all survived a 300F/icewater IWCT test without crazing!

Micro bubbles in low fire glaze. Why?


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Left: G1916Q transparent fired at cone 03 over a black engobe (L3685T plus stain) and a kaolin-based low fire stoneware (L3685T). The micro-bubbles are proliferating when the glaze is too thick. Right: A commercial low fire transparent (two coats lower and 3 coats upper). A crystal clear glaze result is needed and it appears that the body is generating gases that cause this problem. Likely the kaolin is the guilty material, the recipe contains almost 50%. Kaolin has a 12% LOI. To cut this LOI it will be necessary to replace some or all of the kaolin with a low carbon ball clay. This will mean a loss in whiteness. Another solution would be diluting the kaolin with feldspar and adding more bentonite to make up for lost plasticity.

Cone 03 stoneware. Red and white body and slips. Clear glaze.


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Cone 03 white stoneware with red terra cotta ball-milled slip and transparent overglaze. They are L3685U engobe (Ferro frit 3110, #6 tile kaolin, Silica), near the final mix for a white low fire stoneware. The G1916J glaze is super clear. Why? Two reasons. These were fired in a schedule designed to burn off the gases from the bentonite in the body before the glaze fuses (it soaks the kiln for 2 hours at 1400F). Terra cotta clays generate alot of gases at cone 03 (producing glaze micro-bubbles), but here the terra cotta is only a thin slip over the much cleaner burning white body.

Low fire red and white stoneware getting closer


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I have switched to a Redart based red burning low fire stoneware. You can see all my test data on an insight-live share here: http://goo.gl/DOd23J
What are these? The white body matures to less than 2% porosity at cone 03. The red: 4%. The white can also be used as a slip on the red and the red as a slip on the white. The glaze (it is column three on the above share) works on both. They are both really plastic. This is really cool, I cannot wait to get down to the lab tomorrow to trim and slip these.

The value of a white vitreous engobe over terra cotta at cone 03


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At cone 03 many terra cottas will fire quite dense and stoneware-like. The lip of the mug on the left is covered with a vitreous white engobe (L3685U) under the glaze (G1916Q). Red bodies are much stronger at low temperatures, but do not lend themselves well to the bright glaze colors that work so well at that range. Putting an engobe on as a base enables decoration with colored slips and a clear over glaze. One caution: The engobe needs to have the same firing shrinkage as the body, to use a vitreous engobe the body needs a frit addition to be vitreous also. If you put a vitreous engobe on a porous earthenware its firing shrinkage will put it under tension and the poor bond with the body will mean quick or eventual failure.

Links

Recipes G1916Q - Low Fire Highly-Expansion-Adjustable Transparent
An expansion-adjustable cone 04 transparent glaze made using three common Ferro frits (low and high expansion), it produces an easy-to-use slurry.
Recipes L3724F - Cone 03 Terra Cotta Stoneware
An experimental Zero3 using Plainsman 3D clay
Glossary Flocculation
The flocculation process enables technicians in ceramics to create an engobe or glaze slurry that gels and goes on to ware in a thick yet even, non-dripping layer.
Glossary Zero3
The designation for a group recipes for body, glaze and engobe (by Tony Hansen), that potters can use to make low fire stoneware and fritware porcelain at 1100C (2000F) or cone 03.
Media How to Apply a White Slip to Terra Cotta Ware
I will show you some secrets of making a base engobe (or slip) apply to leather hard terracotta ware in a thick, perfectly even layer.
URLs https://insight-live.com/insight/share.php?z=M2WnSWNEry
L3685Y Terrastone Slip

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XML to Paste Into Insight-live

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<recipe name="Cone 03 White Engobe Recipe" keywords="A white burning body with enough added frit to produce a cone 03 stoneware or white slip for use on the matching red Zero3 stoneware." id="109" date="2021-02-01" codenum="L3685U">
<recipelines>
<recipeline material="Nepheline Syenite" amount="10.000"/>
<recipeline material="Tile #6 Kaolin" amount="42.000"/>
<recipeline material="Ferro Frit 3110" amount="25.000"/>
<recipeline material="Silica" amount="20.000"/>
<recipeline material="National Standard Bentonite" amount="5.000"/>
<url url="https://digitalfire.com/recipe/109" descrip="https://digitalfire.com/recipe/109"/>
</recipelines>
<urls/>
</recipe>
</recipes>
By Tony Hansen
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