Old Style THUNDERBIRD Sterling Silver TURQUOISE EARRINGS Arrowhe

This is the Aeroart St Petersburg Russia Medieval Knight Flag Bearer Painted engobe. But it has 15% Mason 6600 black body stain (instead of the normal 10% Zircopax for white). Of course, a cover glaze is needed, but even without it is absolutely coal black (so a lesser stain % is possible). Lots of information is available for L3954B (including mixing instructions showing exact amounts for water, powder, Darvan). Engobes are tricky to use, follow the link above or below to learn more. L3954B is designed to work on regular Plainsman M340 (this piece), Vintage 90s Bill Blass Petite Small Sleeveless Button Front Shir and Coffee Clay, these bodies dry better than porcelains and are much less expensive, coating them with an engobe to get a surface like this makes a lot of sense. This engobe is actually a highly plastic body, but it does not contain enough feldspar to be a porcelain (this is on purpose to match the firing shrinkage of the stonewares).

Potters are used to making dipping glazes that they weigh out and mix from recipes. Hobbyists commonly use bottled commercial brushing glazes. Did you know that a dipping glaze can be turned into a brushing glaze by the addition of Veegum (or Veegum CER) and water? Do you know what a base-coat dipping glaze is? Here is a quick overview: Dipping glazes need to go on to bisque ware evenly, be thixotropic enough to hold on at thickness and drain and dry quickly. But they don't need to dry hard. Brushing glazes need a cohesive slurry that dries slowly and hardens well on drying. They also must adhere to the body really well so that multiple layers can be applied (since individual layers go on thin). Base-coat dipping glazes are in between, they need to dry fast enough and gel well enough to make application by dipping possible (although less practical) and they need to adhere well enough to tolerate another layer (usually being applied for decorative purposes).

Black burning bodies are popular with many potters. They are normally manufactured by adding around 10% burnt or raw umber to an existing buff-burning cone 6 stoneware. Umbers are powerful ZIZILAND Trampoline Shoes bag, they have high iron and also contain manganese (the latter being the primary source of the color). But these clays can be troublesome. First, good kiln venting is needed to avoid breathing the manganese metal vapors for firings going past cone 6. Micro-bubble clouding/gloss-loss in the glazes and blistering/bloating of the bodies are common. But this mug fired perfectly. Why? The umber was added to a cone 10 stoneware instead (and it has fluxed the body to mature at cone 6). The mug has been white engobed, during leather hard stage, using SPI Starter Clutch Drive Gear Kit fits Ski-Doo Sleds Replaces OE on the inside and partway down the outside. After bisque it was clear glazed on the inside giving a flawless surface (using Sun 375-3357 LSI Logic lsi22320sle PCI-E Dual SCSI Ultra 320) and dipped in GA6-A Alberta Slip base amber-clear. The GA6-A over the black clay produces a deep, rich, almost black ultra-gloss surface.

L4496, this clay, is the top two bars, fired at cone 4 and 04. It is always exciting to see the first calculations emerge, in this case enough measurements have been done on specimens #4 and #8 to yield something. The bottom bars are Plainsman L215 terra cotta. But Notice I have enough data entered for these cones that Cinderella Metal Carriage PInk Card Holder/Home Decor can calculate firing shrinkage and water absorption, and the numbers are surprising. Specimen #8 has a firing shrinkage of -0.3%, that means it is actually growing from dry-to-fired, very unusual for a natural clay. Notice also the absorption is only 3.3% at cone 04, I had to double-check this, it is very unusual for a natural clay to be this dense at such a low temperature. Even though the surface of the L215 bar on the bottom is much smoother and denser appearing it is actually much less dense (at 12% porosity). The cone 4 numbers are also interesting. The clay is melting at cone 5 (not shown) but the cone 4 bar is not bloating or bubbling and its firing shrinkage is low.

These screen fragment overlays are from the recipe panel at insight-live.com. The table of data shown here is from the SHAB test only. The row numbers are the specimen numbers of each bar. The first five columns are the data we collected by measuring the bars before and after firing (dry length, fired length, dry weight, fired weight). The last three red columns are the results of calculations it does on that data to produce values for drying shrinkage, firing shrinkage and fired porosity. The graph above charts the firing shrinkage (ascending line) and absorption (descending line) against temperature. These two lines are like a "fired maturity fingerprint". Finding meaning in this data enables characterizing the firing behavior of the clay. In the next step, we will compare it to a terra cotta clay body.

These are the same glazes. The slurry of the one on the left had a specific gravity of 1.45, it was creamy and appeared to be good. However, when this bisque porcelain mug was pulled out after the dip it dried so fast that it would not even out around the lip (in spite of my efforts to roll it). To fix this I added water to increase the specific gravity to 1.43 (making it quite watery). Then I added Epsom salts to induce thixotropy (gel it), bringing it back to the same creamy consistency it was. This time it went on evenly and dried slowly enough that it evened out. Notice the darker color, is it still damp. Although the piece dries enough to handle in less than 30 seconds, it does take longer to dry completely because there is more water in the slurry.

These test bars are fired from cone 5 (top) down to cone 06 (bottom). We are processing hundreds of these bars are any given time, managing the simultaneous testing of dozens of body, glaze and engobe projects in our group account at insight-live.com. These took about a month to work their way through our system, all the measurement data has been entered (we will look at that in the next step). These bars show visually how this clay matures across a wide range of temperatures, from most-porous at the bottom to beginning-to-melt at the top. One thing is obvious: Most terra cottas shrink much more as they approach cone 2, commonly reaching 8%, then they begin to expand above that. This one is much more dimensionally stable, it is only shrinking about 3% at cone 2 (the #2 bar).

This is the G3939A recipe (a 90:10 mix of G2934 and Sigma Sport ANT+ Heartrate Chest Strap / Transmitter Computer Un), it normally produces a silky matte if not cooled too quickly. Shown on the left is our original addition of 8% Mason 6021 red stain and 4.5% titanium dioxide. This not only did not produce the desired marbled effect, it actually made it more glossy! A 1.5% titanium addition completely transforms it to what you see on the right. Rutile, as a source of COLOMBIA - RARE SILVER 1/4 REAL VF COIN 1851 YEAR KM#108.2 POPAY, is often used for this, but it is high in iron and would completely muddy the red color. Pure titanium dioxide, by contrast, is iron free.

These porcelain mugs have the same glaze, the one on the left was fired at cone 10R (gas), the other at cone 10 oxidation (electric). This is our standard cone 10R magnesia matte, G2571B. We have added a 5% Mason 6021 encapsulated red stain and 4% titanium dioxide (producing recipe code number G2571D). While the reduction version looked good the oxidation one turned out much more vibrant. And it feels much better, being very pleasant to touch. The marbling is a bit excessive so in G2571D1 we reduced the titanium by 1% (and increased the stain by 1%). MgO matte base recipes are very receptive to this type of adjustment and they work across a wide range (from low to high temperatures). Titanium is much better for variegating bright colored glazes than rutile, because the latter contains lots of iron that muddies the color.

This is one-quarter of the DFAC test disk (this simple test enables us to rate the drying performance, dry strength and soluble salts). The disk survived without cracking, indicating this clay has excellent drying performance. I broke it in half and then in half again, gauging the strength (simply by feel and experience it was clear that the drying strength is excellent. Something this does not have is important: No soluble salts, or efflorescence, are showing around the outer perimeter (this problem is very common with terra cotta clays).