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.


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

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

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.

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)

<recipes>XML not functional: We are working on this problem.</recipes>

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

M340 Casting Body

Code #

L3798C

Materials Amt
*KT1-4 Ball Clay 25.000
Silica 25.000
Nepheline Syenite 17.000
Pioneer Kaolin 25.000
Redart 8.000

Total:100.00

Notes

This is version 4. 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 easier to use than a whitewares (like M370) and fires as strong (or even stronger since glaze fit is better).

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

This substitutes a larger particle size ball clay and kaolin in L3798B, the previous version, to achieve faster casting (otherwise the recipe is the same). This change also enabled lowering the percentage of Darvan which made it eaiser to mix. The version before that, 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 the RedArt does not flocculate and gel the casting slip the way added iron oxide would.

While casting performance is better, it is still best for studio situations (for industrial it would be better to use a still larger-particle kaolin and substitute some of the ball clay for more kaolin). 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.

Typical recipe: 7000 powder, 2800 water, 31 Darvan. That produces 1.8 specific gravity and fills a 2 US gallon bucket half full.
Try to mix it to a smooth slurry that has enough fluidity to move well. 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.

Pictures

L3798C cast mugs

L3798C bamboo glazed mugs

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L3798C mugs with G1947U and GR10A glazes

Cone 11R

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XML (to paste into Insight)

<recipes>XML not functional: We are working on this problem.</recipes>

Born: 2017-08-01, Modified: 2020-01-04 19:13:03