M340 and M390 Casting Bodies

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Recipes of refined materials that have similar fired maturity and thermal expansions to Plainsman M340, M390. Intended for using in make objects that combine plastic forming and casting.


M340 Casting Body

Code #

L3798B

Materials Amt
M-23 Ball Clay 25.000
Silica 25.000
Nepheline Syenite 17.000
EPK 25.000
Redart 8.000

Total:100.00

R2O3 Unity Formula + Analysis

CaO 0.02 0.19%
MgO 0.03 0.22%
K2O 0.07 1.35%
Na2O 0.13 1.73%
(KNaO) 0.20
TiO2 0.03 0.56%
P2O5 0.00 0.08%
Al2O3 1.00 21.49%
SiO2 5.25 66.68%
Fe2O3 0.03 1.03%

Ratios

Si:Al: 5.3:1
R2O:RO: 0.8:0.2

Expansion

5.4

LOI

6.7

Cost

62.74 per kg

Notes

This is version 3. The objective was to develop one that is similar to Plainsman M340 at cone 6 (has the a similar fired maturity (firing shrinkage and porosity), fired color and easy glaze fit). M340 is robust in production (fewer pieces are lost to breakage, warping, glaze fit issues, cracking, bloating, etc). This body, likewise, is much easier to use than a whitewares (like M370) and fires as strong (or even stronger since glaze fit better).

Because this is made from refined minerals it sacrifices the rustic (speckled, variegated) appearance of M340.

The previous version, L3798A, lacked fired maturity and was burning too light in color (this has more Redart at the expense of Nepheline Syenite). Redart is a low melting clay and in this context it imparts the bone color needed and really improves vitrification (more than is practical by simply adding more nepheline syenite). An added benefit is that it does not flocculate and gel the casting slip the way added iron oxide would.

Casting performance is OK for studio situations, it will need about 20 minutes in a good mold to get a 4mm wall thickness (for industrial it would be better to use a large-particle ball clay and kaolin to optimize casting time). This body is easier to deflocculate than a porcelain. It is plastic, it has the strength to pull away from the mold as it shrinks.

To make a casting slip from 2000 grams of powdered body mix start with 800 grams of water and 8 grams of Darvan. Try to mix it to a smooth slurry that has enough fluidity to move well. If needed add a little more Darvan (but be careful, you should not need more than 10g). Measure the specific gravity accurately (weighing, not a hydrometer). If it is higher than 1.75 add a little water to bring it down (about 50cc) and measure again. If the slurry is too viscous or is gelling add tiny amounts of Darvan until it is right. Do not add so much Darvan that it becomes too thin (it will settle out). It should gel after sitting for half an hour or more.

URLs

Understanding the Deflocculation Process

Pictures

IMG_2408

P3798 M340 casting body bars vs. M340

Top groups of bars: cone 6 (M340 center, L3798B below, A above). Bottom group: cone 7.
This version fires more of a pinkish tan whereas M340 is greenish tan.

Bowls cast with L3798B M340 Casting

Cone 6. These 4.5 inch bowls are an unstable shape and normally warp to oval on firing. The wall thickness is much thinner than a thrown bowl could be. This is demonstrating excellent firing stability
.
Left: G2926B Whiteware clear. Right: GA6-A Alberta Slip base (using Frit 3195). Both survived a 300F-to-ice-water thermal shock without crazing. The good fit with these glazes adds considerable strength to the pieces.

M340 casting vs. M340 plastic body

Fired at cone 6 with G2926B Whiteware clear glaze. The colors do not match perfectly.

Obviously the M340 has a fine speckle that the casting version does not have. If this is a concern you will need to add a tiny percentage of a specking agent (perhaps about 0.1% of 80-100 mesh screenings of Illmenite).

L3798B casting at cone 6 without glaze

Very warm stoneware color.
This was not cast, it was made into the plastic form and thrown.

Untitled

Testdata

SHAB - Shrinkage/Absorption

DLEN FLEN FWT BWT CONE DSHR FSHR ABS
4 94.33 87.41 37.76 39.22 4.8 5.7% 7.3% 3.9%
5 94.35 87.61 37.72 39.19 4.8 5.7% 7.1% 3.9%
6 94.55 87.61 38.2 39.24 5.8 5.5% 7.3% 2.7%
7 94.63 87.01 36.7 37.34 6.7 5.4% 8.1% 1.7%
8 94.62 87.42 36.52 36.95 7.8 5.4% 7.6% 1.2%

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="M340 Casting Body" id="115788" key="xTLfdKe9" date="2018-04-27" codenum="L3798B" picturebasename=""> <recipelines> <recipeline material="M-23 Ball Clay" amount="25.000"/> <recipeline material="Silica" amount="25.000"/> <recipeline material="Nepheline Syenite" amount="17.000"/> <recipeline material="EPK" amount="25.000"/> <recipeline material="Redart" amount="8.000"/> </recipelines> </recipe> </recipes>

Born: 2017-08-01, Modified: 2018-04-27 16:44:04

M390 Casting

Code #

L4005

Materials Amt
M-23 Ball Clay 35.000
Silica 25.000
Redart 40.000

Total:100.00

Notes

A red firing cone 6 casting body. Created to fire to a similar color and have a similar degree of vitrification to Plainsman M390.

This does not deflocculate as easily at the M340 casting. In 2000 grams of powdered body mix start with 900 grams of water and 12 grams of Darvan. Try to mix it to a smooth slurry that has enough fluidity to move well. If needed add a little more Darvan. If the slurry is too viscous or is gelling add tiny amounts of Darvan until it is right. Do not add so much Darvan that it becomes too thin (it will settle out). It should gel after sitting for a while.

URLs

Understanding the deflocculation process

Pictures

Thinner walled cast piece fires browner

Mug handle is made from regular pugged M390, dried with no issues and the glaze appears the same on both.

M390 Casting with clear glaze inside, rutile blue outside

Inner glaze surface is high quality and defect free. The milkiness is from very tiny bubbles, but it is still a pleasing effect.

M390 casting fired at cone 6

Although this is a casting body, this cup was thrown from the plastic form. The body is not very plastic, but that is intentional to get the fastest casting time.

Color is a very warm red. However there are some soluble salts that migrate to the surface during drying and make some areas fire darker than others.

L4005 M390 casting vs. P6586 fired bars

Variations

A - With Darvan 811

Tried a mix: 2750 grams powder (This is 69.62%) 1200 grams water (This is 30.38%) Add: 18 grams Darvan #811 (This is .46% of total of above powder/water combination totaling 100%). S.G. 1.775

Testdata

SHAB - Shrinkage/Absorption

DLEN FLEN FWT BWT CONE DSHR FSHR ABS
4 93.67 88.97 36.65 38.95 4.0 6.3% 5.0% 6.3%
5 93.66 88.67 37.01 38.88 4.8 6.3% 5.3% 5.1%
6 93.75 88.04 35.5 36.49 6.0 6.3% 6.1% 2.8%
7 93.77 87.39 34.9 35.35 6.8 6.2% 6.8% 1.3%
8 93.66 87.21 33.88 34.19 8.1 6.3% 6.9% 0.9%

LDW - LOI/Density/Water Content

WWGT DWGT H2O LOI DENS
1 23.4 18.3 21.8%

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="M390 Casting" id="116346" key="i43Byie4" date="2018-11-05" codenum="L4005"> <recipelines> <recipeline material="M-23 Ball Clay" amount="35.000"/> <recipeline material="Silica" amount="25.000"/> <recipeline material="Redart" amount="40.000"/> </recipelines> </recipe> </recipes>

Born: 2017-09-05, Modified: 2018-11-05 14:59:13