Cone 10R Base Engobe

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These two variations of the recipe match fired shrinkages to the specifically named bodies (of course, they should fit any body having a similar fired shrinkage). For a zero-porosity porcelain (e.g. Grolleg), try increasing nepheline to 20 at the expense of ball clay.


Cone 10 Engobe for H550

White

Code #

L3954N

Batch #

3

Materials Amt
Nepheline Syenite 10.000
Silica 20.000
OM #4 Ball Clay 60.000
Bentonite 2.000
Additions
Zircopax 10.000
*Mason 6600 Black Stain 10.000

Total:112.00

Auto Unity Formula + Analysis

CaO 0.02 0.20%
MgO 0.05 0.34%
K2O 0.07 1.11%
Na2O 0.10 1.13%
(KNaO) 0.17
TiO2 0.08 1.16%
Al2O3 1.00 17.96%
SiO2 6.08 64.38%
Fe2O3 0.03 0.83%
ZrO2 0.30 6.52%

Ratios

Si:Al: 6.1:1
R2O:RO: 0.7:0.3

Expansion

5.5 (Molar:5.0)

LOI

6.4

Notes

*Both Zircopax and Black Stain are shown as additions. Use one or the other (to get white or black).

This recipe the product of a series of tests where the percentage of nepheline syenite was progressively reduced (from 25% originally) to reduce the firing shrinkage to match H550 (it is important that engobes shrink the same as the body or they will flake or crack off during firing or later during ware use). Amazingly only 10% nepheline syenite is needed to make this fit Plainsman H450, H550. Again, do not use this recipe on porcelains (e.g. P700) or whitewares (e.g. H570, P600), the recipe needs more nepheline for them (to increase firing shrinkage, we have another recipe, L3954J that does this).

This creates very plastic slurry so it sticks well to leather hard clay (because of the high percentage of ball clay). If you do not have this brand name of ball clay then substitute another.

The Zircopax version fires quite white, leave it out completely if that is too white. If on thick enough this will block and body speckling, glazes will react as if on porcelain.

As an engobe this works best when mixed as a thixotropic slurry. Please follow the instructions for the cone 6 version at the L3954B page at the Plainsman Clays website.

Pictures

Untitled

AC829106-81A4-44B7-BF33-019A6D89C9D4

Variations

1 - Black

We normally use 10% black stain, but have tested lesser amounts down to 5%. Just use as much as you need to get the degree of black you want.

Testdata

SHAB - Shrinkage/Absorption

DLEN FLEN FWT BWT CONE DSHR FSHR ABS
1093.2385.741.4142.110.06.8%8.1%1.7%
1293.2985.3039.5040.2310.0R6.7%8.6%1.8%
993.1986.2440.6141.659.06.8%7.5%2.6%
893.3586.7142.3943.878.06.7%7.1%3.5%
793.0587.1240.3842.147.07.0%6.4%4.4%
693.2887.7540.642.936.06.7%5.9%5.7%
593.3588.6340.5343.625.06.7%5.1%7.6%
493.5189.2439.1442.854.06.5%4.6%9.5%

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Cone 10 Engobe for H550" keywords="White" id="136925" key="W56BSXCi" date="2024-09-02" codenum="L3954N"> <recipelines> <recipeline material="Nepheline Syenite" amount="10.000" tolerance=""/> <recipeline material="Silica" amount="20.000" tolerance=""/> <recipeline material="OM #4 Ball Clay" amount="60.000" tolerance=""/> <recipeline material="Bentonite" amount="2.000" tolerance=""/> <recipeline material="Zircopax" amount="10.000" added="true"/> <recipeline material="Mason 6600 Black Stain" amount="10.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2016-12-12, Modified: 2024-09-02 04:28:23

Black Cone 10 Whiteware Engobe Recipe

For Plainsman H570

Code #

L3954J

Batch #

3

Materials Amt
Nepheline Syenite 15.000 16.76%
Silica 15.000 16.76%
Ball Clay 57.000 63.69%
Bentonite 2.500 2.79%
Additions
*Mason 6600 Black 10.000 11.17%

Total:99.50

Notes

*This is a variation on L3954N. This has a higher fired shrinkage to match more vitreous bodies (like Plainsman H570, P580 which have 0.5-1% fired porosity). However this does not shrink enough to match a vitreous Grolleg porcelain (like P700), more nepheline would be needed.

Batch Ticket Notes

Mixed 3000 grams powder. with 2380 water to get SG 1.47. Darvan 9.5g.

April 10/18 Joe tried a gum version:
L3954J powder 500 gms.
Water 280 grams
Laguna Gum Solution 75 grams.
This just so fits in a 1 pint jar.

This flakes on the insides of P700 pieces and pulls dramatically toward itself on an EBCT with P700.

Pictures

H570 P6629 has no solubles, works with black slip

L3954J engobe fit is perfect (as can be seen on the straight CLWC engobe compatibility test bars.

Something is wrong because the engobe shrinks 2% more on firing.

G2571A on H450 with L3954J black engobe

Fired at cone 10R. The black engobe has been applied inside and half way down the outsides.
Glaze on left is G2571A with 5% added rutile (Bamboo).
On the inside of the first mug is GR10-C Ravenscrag silky matte. The black engobe appears black under the clear glaze but brown under the bamboo glaze.

L3954J Engobe fit cone 10R

Back to front: H450, H550, H570 and white version of same engobe
For some reason the fit is almost perfect on all except H550 (toward 550 on drying, toward J on firing for a total of 7mm).

L3954J and H are compatible

The black stain is not changing the fired shrinkage.

G2571A of black and brown L3954 engobe

On H450 at cone 10R

L3954 cone 10R engobe fired bars

On P700 flakes inside, outside OK

The shrinkage difference is not great enough for this dramatic result so the engobe is not forming a good bond with the porcelain.

With P700

Pulls 11 toward the J on drying and then back straight on firing. That means the J needs less firing shrinkage, more drying shrinkage to work with P700.

Testdata

SHAB - Shrinkage/Absorption

DLEN FLEN FWT BWT CONE DSHR FSHR ABS
1094.1687.7139.2240.9410.05.8%6.9%4.4%
1294.1886.3637.7737.7710R5.8%8.3%0.0%
894.0486.6539.739.748.06.0%7.9%0.1%

EBCT - Engobe Body Compatibility Test

MATA MATB BNDR BNFR BCON
1engobeH4504.7/4502/45010R
2engobeH570.5/570.7/57010R
3G3954HG3954J3mm/J1.5mm/J10R
4H55OL3954J3.5/H5503.5/J10R
5P700L3954J11/J0/J10R

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Black Cone 10 Whiteware Engobe Recipe" keywords="For Plainsman H570" id="130962" key="eGZnJ1AS" date="2023-05-28" codenum="L3954J"> <recipelines> <recipeline material="Nepheline Syenite" amount="15.000" tolerance=""/> <recipeline material="Silica" amount="15.000" tolerance=""/> <recipeline material="Ball Clay" amount="57.000" tolerance=""/> <recipeline material="Bentonite" amount="2.500" tolerance=""/> <recipeline material="Mason 6600 Black" amount="10.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2016-12-12, Modified: 2023-05-28 21:15:53

Variation of Recipe L3954N

Cone 10 Engobe for H550

Code Number Extension

L3954N - 1

Recipe Name Extension

Black


Base Recipe For This Variation

Materials Amt
Nepheline Syenite 10.000
Silica 20.000
OM #4 Ball Clay 60.000
Bentonite 2.000
Additions
Mason 6600 10.000

Total:102.00

Auto Unity Formula + Analysis

CaO 0.02 0.23%
MgO 0.05 0.38%
K2O 0.07 1.23%
Na2O 0.10 1.26%
(KNaO) 0.17
TiO2 0.08 1.30%
Al2O3 1.00 20.04%
SiO2 5.78 68.28%
Fe2O3 0.03 0.93%

Ratios

Si:Al: 5.8:1
R2O:RO: 0.7:0.3

Expansion

5.2 (Molar:4.9)

LOI

6.4

Cost

5.03 per kg

Notes for this variation

We normally use 10% black stain, but have tested lesser amounts down to 5%. Just use as much as you need to get the degree of black you want.

Pictures

L3954N black On L4048A H550

L3954N Black on L4048A H550 Test

Black cone 10R slip fired bar

Testdata

SHAB - Shrinkage/Absorption

DLEN FLEN FWT BWT CONE DSHR FSHR ABS
1292.7785.4343.2643.8810.5R7.2%7.9%1.4%

EBCT - Engobe Body Compatibility Test

MATA MATB BNDR
1L4050AL3954N-115/L4050A
2L4048AL3954N10/L4048A