2662 | 2663 | 2660 | 2661 | 2656 | 2657 | 2658 | 2659 | 2655 | 2654 | 2653 | 2652 | 2649 | 2650 | 2651 | 2646 | 2647 | 2648 | 2643 | 2644 | 2641 | 2642 | 2639 | 2640 | 2637 | 2638 | 2635 | 2636 | 2633 | 2634 | 2631 | 2632 | 2630 | 2629 | 2627 | 2628 | 2624 | 2625 | 2626 | 2621 | 2622 | 2623 | 2618 | 2619 | 2617 | 2614 | 2615 | 2616 | 2613 | 2612 | 2607 | 2608 | 2609 | 2610 | 2611 | 2606 | 2605 | 2602 | 2603 | 2604 | 2600 | 2601 | 2599 | 2598 | 2597 | 2591 | 2592 | 2593 | 2594 | 2585 | 2586 | 2587 | 2588 | 2589 | 2590 | 2584 | 2583 | 2582 | 2581 | 2578 | 2580 | 2576 | 2577 | 2573 | 2574 | 2575 | 2572 | 2571 | 2566 | 2567 | 2568 | 2569 | 2570 | 2563 | 2564 | 2565 | 2562 | 2561 | 2560 | 2558 | 2559 | 2557 | 2556 | 2554 | 2555 | 2551 | 2552 | 2553 | 2548 | 2549 | 2550 | 2545 | 2546 | 2542 | 2543 | 2544 | 2540 | 2541 | 2539 | 2538 | 2537 | 2536 | 2533 | 2534 | 2535 | 2531 | 2532 | 2530 | 2528 | 2527 | 2524 | 2522 | 2523 | 2521 | 2519 | 2520 | 2518 | 2517 | 2516 | 2515 | 2514 | 2513 | 2511 | 2512 | 2509 | 2508 | 2506 | 2507 | 2505 | 2504 | 2503 | 2502 | 2501 | 2499 | 2490 | 2494 | 2495 | 2496 | 2497 | 2498 | 2489 | 2488 | 2487 | 2486 | 2485 | 2484 | 2483 | 2482 | 2481 | 2479 | 2480 | 2478 | 2474 | 2475 | 2476 | 2477 | 2472 | 2473 | 2471 | 2470 | 2465 | 2466 | 2467 | 2468 | 2469 | 2464 | 2461 | 2463 | 2460 | 2459 | 2458 | 2457 | 2454 | 2455 | 2456 | 2451 | 2452 | 2453 | 2449 | 2450 | 2447 | 2448 | 2442 | 2443 | 2444 | 2445 | 2446 | 2440 | 2441 | 2439 | 2436 | 2437 | 2438 | 2434 | 2435 | 2433 | 2432 | 2429 | 2430 | 2431 | 2425 | 2426 | 2427 | 2428 | 2422 | 2423 | 2424 | 2421 | 2417 | 2418 | 2419 | 2420 | 2416 | 2415 | 2412 | 2411 | 2410 | 2408 | 2409 | 2407 | 2406 | 2405 | 2403 | 2404 | 2402 | 2401 | 2400 | 2399 | 2398 | 2397 | 2396 | 2395 | 2394 | 2392 | 2393 | 2390 | 2389 | 2387 | 2386 | 2385 | 2384 | 2383 | 2380 | 2375 | 2376 | 2377 | 2378 | 2379 | 2374 | 2373 | 2372 | 2371 | 2369 | 2370 | 2366 | 2368 | 2361 | 2362 | 2363 | 2364 | 2365 | 2360 | 2358 | 2359 | 2355 | 2356 | 2357 | 2354 | 2353 | 2350 | 2351 | 2348 | 2349 | 2346 | 2347 | 2344 | 2345 | 2343 | 2342 | 2341 | 2337 | 2339 | 2340 | 2335 | 2336 | 2334 | 2333 | 2328 | 2329 | 2330 | 2331 | 2332 | 2327 | 2326 | 2323 | 2324 | 2325 | 2322 | 2321 | 2316 | 2317 | 2318 | 2319 | 2320 | 2314 | 2315 | 2311 | 2312 | 2313 | 2309 | 2308 | 2306 | 2307 | 2304 | 2305 | 2303 | 2299 | 2300 | 2301 | 2297 | 2294 | 2295 | 2296 | 2292 | 2278 | 2279 | 2280 | 2281 | 2282 | 2283 | 2284 | 2285 | 2286 | 2287 | 2288 | 2289 | 2290 | 2273 | 2274 | 2275 | 2276 | 2277 | 2271 | 2272 | 2270 | 2269 | 2267 | 2266 | 2265 | 2263 | 2264 | 2262 | 2260 | 2261 | 2259 | 2258 | 2257 | 2255 | 2256 | 2254 | 2250 | 2252 | 2249 | 2247 | 2248 | 2246 | 2242 | 2243 | 2245 | 2239 | 2240 | 2241 | 2235 | 2236 | 2237 | 2238 | 2234 | 2233 | 2232 | 2231 | 2230 | 2229 | 2225 | 2226 | 2224 | 2222 | 2223 | 2220 | 2221 | 2218 | 2219 | 2216 | 2217 | 2214 | 2215 | 2213 | 2211 | 2212 | 2210 | 2209 | 2208 | 2207 | 2206 | 2205 | 2203 | 2204 | 2202 | 2201 | 2199 | 2200 | 2198 | 2197 | 2195 | 2196 | 2194 | 2192 | 2193 | 2191 | 2189 | 2190 | 2188 | 2186 | 2187 | 2185 | 2184 | 2182 | 2183 | 2180 | 2178 | 2179 | 2176 | 2177 | 2172 | 2173 | 2174 | 2175 | 2171 | 2166 | 2167 | 2168 | 2169 | 2170 | 2165 | 2156 | 2157 | 2158 | 2159 | 2161 | 2162 | 2164 | 2153 | 2154 | 2155 | 2151 | 2150 | 2148 | 2149 | 2142 | 2143 | 2144 | 2145 | 2146 | 2147 | 2140 | 2141 | 2138 | 2139 | 2136 | 2137 | 2135 | 2129 | 2130 | 2131 | 2132 | 2133 | 2134 | 2128 | 2127 | 2126 | 2125 | 2124 | 2121 | 2122 | 2123 | 2119 | 2118 | 2117 | 2115 | 2116 | 2114 | 2113 | 2112 | 2111 | 2109 | 2108 | 2107 | 2106 | 2104 | 2105 | 2101 | 2102 | 2103 | 2099 | 2100 | 2096 | 2097 | 2094 | 2095 | 2093 | 2092 | 2091 | 2089 | 2090 | 2088 | 2087 | 2086 | 2085 | 2084 | 2082 | 2083 | 2081 | 2078 | 2079 | 2080 | 2076 | 2077 | 2073 | 2074 | 2075 | 2072 | 2071 | 2069 | 2066 | 2067 | 2068 | 2065 | 2064 | 2060 | 2061 | 2062 | 2059 | 2057 | 2058 | 2052 | 2053 | 2054 | 2055 | 2056 | 2049 | 2050 | 2051 | 2048 | 2047 | 2046 | 2042 | 2043 | 2044 | 2045 | 2040 | 2039 | 2038 | 2036 | 2035 | 2029 | 2030 | 2031 | 2033 | 2034 | 2027 | 2024 | 2025 | 2026 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2016 | 2015 | 2014 | 2013 | 2010 | 2011 | 2012 | 2008 | 2009 | 2007 | 2001 | 2002 | 2003 | 2004 | 2005 | 1993 | 1995 | 1998 | 2000 | 1990 | 1991 | 1987 | 1988 | 1986 | 1983 | 1984 | 1976 | 1977 | 1978 | 1979 | 1980 | 1981 | 1982 | 1974 | 1975 | 1973 | 1972 | 1970 | 1968 | 1969 | 1967 | 1966 | 1965 | 1964 | 1962 | 1961 | 1959 | 1960 | 1955 | 1956 | 1957 | 1954 | 1952 | 1953 | 1950 | 1951 | 1948 | 1947 | 1946 | 1944 | 1945 | 1940 | 1941 | 1942 | 1943 | 1939 | 1934 | 1935 | 1936 | 1937 | 1938 | 1932 | 1933 | 1931 | 1930 | 1928 | 1927 | 1922 | 1923 | 1924 | 1925 | 1926 | 1916 | 1918 | 1919 | 1920 | 1921 | 1915 | 1914 | 1906 | 1907 | 1908 | 1909 | 1910 | 1911 | 1912 | 1913 | 1902 | 1904 | 1905 | 1895 | 1896 | 1897 | 1899 | 1900 | 1901 | 1891 | 1893 | 1894 | 1890 | 1888 | 1889 | 1887 | 1885 | 1882 | 1883 | 1884 | 1874 | 1875 | 1876 | 1877 | 1879 | 1869 | 1870 | 1871 | 1872 | 1873 | 1868 | 1867 | 1866 | 1865 | 1864 | 1856 | 1857 | 1858 | 1859 | 1860 | 1861 | 1862 | 1863 | 1854 | 1855 | 1850 | 1851 | 1852 | 1848 | 1849 | 1846 | 1847 | 1843 | 1844 | 1845 | 1842 | 1831 | 1832 | 1833 | 1834 | 1835 | 1836 | 1838 | 1839 | 1840 | 1841 | 1828 | 1829 | 1830 | 1827 | 1826 | 1825 | 1823 | 1824 | 1818 | 1819 | 1820 | 1821 | 1822 | 1817 | 1815 | 1816 | 1814 | 1812 | 1811 | 1809 | 1810 | 1807 | 1806 | 1805 | 1804 | 1803 | 1802 | 1796 | 1797 | 1798 | 1799 | 1800 | 1801 | 1792 | 1793 | 1794 | 1791 | 1790 | 1789 | 1788 | 1786 | 1785 | 1781 | 1782 | 1783 | 1784 | 1780 | 1779 | 1776 | 1775 | 1772 | 1773 | 1770 | 1769 | 1768 | 1767 | 1763 | 1765 | 1766 | 1762 | 1760 | 1761 | 1757 | 1758 | 1759 | 1755 | 1749 | 1750 | 1751 | 1752 | 1753 | 1754 | 1748 | 1747 | 1745 | 1744 | 1742 | 1743 | 1739 | 1740 | 1736 | 1737 | 1735 | 1733 | 1732 | 1729 | 1730 | 1731 | 1722 | 1723 | 1726 | 1727 | 1716 | 1717 | 1718 | 1715 | 1714 | 1712 | 1713 | 1711 | 1710 | 1709 | 1708 | 1706 | 1705 | 1699 | 1700 | 1701 | 1702 | 1703 | 1704 | 1693 | 1694 | 1695 | 1696 | 1697 | 1692 | 1687 | 1690 | 1691 | 1685 | 1686 | 1683 | 1684 | 1682 | 1681 | 1679 | 1677 | 1678 | 1675 | 1674 | 1671 | 1672 | 1669 | 1668 | 1665 | 1666 | 1667 | 1663 | 1662 | 1659 | 1658 | 1657 | 1651 | 1652 | 1653 | 1654 | 1655 | 1656 | 1650 | 1639 | 1640 | 1641 | 1642 | 1643 | 1644 | 1645 | 1646 | 1647 | 1648 | 1649 | 1638 | 1637 | 1636 | 1630 | 1631 | 1632 | 1634 | 1635 | 1628 | 1623 | 1625 | 1626 | 1627 | 1618 | 1619 | 1622 | 1614 | 1615 | 1616 | 1617 | 1613 | 1603 | 1606 | 1607 | 1608 | 1609 | 1610 | 1611 | 1612 | 1591 | 1592 | 1593 | 1594 | 1595 | 1596 | 1597 | 1598 | 1599 | 1600 | 1602 | 1578 | 1579 | 1580 | 1581 | 1582 | 1583 | 1584 | 1585 | 1586 | 1587 | 1588 | 1589 | 1590 | 1576 | 1577 | 1575 | 1574 | 1573 | 1570 | 1565 | 1566 | 1567 | 1568 | 1569 | 1564 | 1560 | 1559 | 1555 | 1556 | 1557 | 1558 | 1551 | 1553 | 1554 | 1548 | 1549 | 1550 | 1547 | 1545 | 1546 | 1543 | 1544 | 1537 | 1538 | 1542 | 1533 | 1531 | 1529 | 1528 | 1525 | 1526 | 1527 | 1523 | 1524 | 1521 | 1520 | 1517 | 1518 | 1519 | 1515 | 1516 | 1509 | 1510 | 1511 | 1504 | 1505 | 1506 | 1507 | 1508 | 1499 | 1500 | 1501 | 1502 | 1503 | 1497 | 1498 | 1492 | 1493 | 1494 | 1495 | 1496 | 1489 | 1488 | 1487 | 1485 | 1486 | 1484 | 1479 | 1481 | 1483 | 1621 | 1477 | 1476 | 1472 | 1473 | 1471 | 1470 | 1468 | 1469 | 1467 | 1454 | 1455 | 1457 | 1458 | 1459 | 1460 | 1461 | 1462 | 1463 | 1453 | 1452 | 1451 | 1446 | 1447 | 1448 | 1449 | 1450 | 1442 | 1443 | 1432 | 1433 | 1435 | 1436 | 1437 | 1438 | 1439 | 1341 | 1342 | 1343 | 1344 | 1339 | 1340 | 1337 | 1329 | 1330 | 1331 | 1332 | 1333 | 1335 | 1328 | 1327 | 1321 | 1322 | 1323 | 1324 | 1325 | 1326 | 1320 | 1301 | 1302 | 1305 | 1297 | 1298 | 1299 | 1300 | 1291 | 1292 | 1293 | 1295 | 1296 | 1290 | 1280 | 1281 | 1282 | 1285 | 1286 | 1287 | 1288 | 1279 | 1276 | 1277 | 1278 | 1275 | 1264 | 1265 | 1266 | 1268 | 1269 | 1270 | 1271 | 1272 | 1273 | 1261 | 1262 | 1259 | 1260 | 1257 | 1258 | 1255 | 1254 | 1252 | 1250 | 1249 | 1247 | 1243 | 1244 | 1245 | 1246 | 1241 | 1242 | 1240 | 1238 | 1239 | 1237 | 1236 | 1235 | 1231 | 1232 | 1233 | 1234 | 1227 | 1228 | 1229 | 1230 | 1224 | 1225 | 1226 | 1223 | 1220 | 1221 | 1222 | 1215 | 1216 | 1217 | 1218 | 1211 | 1212 | 1213 | 1209 | 1210 | 1208 | 1202 | 1204 | 1205 | 1206 | 1207 | 1200 | 1201 | 1199 | 1196 | 1198 | 1192 | 1193 | 1189 | 1190 | 1191 | 1185 | 1178 | 1179 | 1180 | 1181 | 1182 | 1184 | 1166 | 1167 | 1168 | 1169 | 1171 | 1173 | 1174 | 1164 | 1162 | 1163 | 1153 | 1154 | 1155 | 1156 | 1157 | 1158 | 1159 | 1160 | 1161 | 1151 | 1152 | 1147 | 1148 | 1149 | 1146 | 1142 | 1143 | 1144 | 1145 | 1138 | 1140 | 1136 | 1133 | 1134 | 1135 | 1132 | 629 | 1130 | 1131 | 1129 | 1123 | 1124 | 1125 | 1126 | 1127 | 1128 | 1122 | 1121 | 1120 | 1119 | 1116 | 1117 | 1118 | 1115 | 1114 | 1108 | 1109 | 1111 | 1112 | 1113 | 1107 | 1106 | 1099 | 1100 | 1101 | 1102 | 1103 | 1098 | 1094 | 1095 | 1097 | 1093 | 1091 | 1092 | 1089 | 1090 | 1088 | 1085 | 1086 | 1083 | 679 | 1081 | 1082 | 1078 | 1079 | 1080 | 1076 | 1077 | 1075 | 1074 | 743 | 1072 | 1073 | 1070 | 1071 | 1069 | 1068 | 1067 | 1057 | 1058 | 1059 | 1060 | 1061 | 1062 | 1063 | 1064 | 1065 | 1066 | 1056 | 1055 | 730 | 1047 | 1048 | 1049 | 1050 | 1051 | 1052 | 1053 | 1042 | 1043 | 1044 | 1045 | 1046 | 1036 | 1037 | 1038 | 1039 | 1040 | 1041 | 1034 | 1035 | 910 | 1032 | 935 | 1030 | 1031 | 1026 | 1027 | 1028 | 1029 | 1024 | 1025 | 1023 | 1021 | 1022 | 1018 | 1020 | 1017 | 684 | 1016 | 1015 | 890 | 1014 | 1011 | 1012 | 1013 | 1010 | 1009 | 1008 | 1007 | 660 | 1006 | 690 | 1005 | 1002 | 1003 | 1004 | 997 | 999 | 1000 | 1001 | 996 | 995 | 994 | 993 | 987 | 988 | 989 | 990 | 991 | 992 | 984 | 985 | 986 | 431 | 983 | 982 | 979 | 980 | 981 | 961 | 977 | 978 | 975 | 976 | 972 | 974 | 969 | 970 | 971 | 968 | 911 | 967 | 817 | 850 | 853 | 658 | 659 | 439 | 966 | 964 | 963 | 960 | 958 | 959 | 957 | 954 | 955 | 956 | 952 | 953 | 949 | 950 | 951 | 947 | 948 | 946 | 945 | 944 | 943 | 942 | 941 | 938 | 936 | 937 | 934 | 931 | 932 | 933 | 752 | 292 | 815 | 816 | 819 | 316 | 832 | 839 | 328 | 846 | 847 | 854 | 855 | 863 | 864 | 865 | 362 | 879 | 888 | 891 | 918 | 716 | 722 | 724 | 741 | 744 | 746 | 749 | 929 | 927 | 928 | 925 | 926 | 924 | 153 | 923 | 919 | 921 | 922 | 916 | 914 | 912 | 908 | 909 | 907 | 905 | 906 | 464 | 354 | 904 | 878 | 900 | 893 | 894 | 895 | 896 | 897 | 892 | 898 | 899 | 889 | 351 | 885 | 886 | 880 | 881 | 883 | 884 | 667 | 874 | 875 | 361 | 930 | 940 | 429 | 430 | 873 | 825 | 826 | 828 | 829 | 844 | 845 | 849 | 852 | 856 | 857 | 858 | 859 | 860 | 870 | 871 | 697 | 764 | 862 | 861 | 818 | 851 | 663 | 830 | 831 | 833 | 834 | 835 | 836 | 840 | 841 | 842 | 843 | 824 | 822 | 820 | 801 | 810 | 811 | 812 | 814 | 628 | 656 | 657 | 661 | 662 | 664 | 665 | 666 | 668 | 669 | 670 | 674 | 675 | 677 | 678 | 680 | 681 | 682 | 683 | 685 | 686 | 687 | 688 | 691 | 692 | 693 | 694 | 699 | 700 | 701 | 702 | 703 | 704 | 705 | 713 | 459 | 715 | 717 | 719 | 720 | 721 | 725 | 729 | 731 | 734 | 736 | 740 | 748 | 751 | 754 | 755 | 756 | 757 | 758 | 759 | 760 | 761 | 711 | 813 | 809 | 808 | 803 | 805 | 364 | 802 | 799 | 800 | 798 | 796 | 797 | 795 | 791 | 792 | 793 | 794 | 461 | 790 | 786 | 787 | 788 | 770 | 771 | 772 | 773 | 774 | 775 | 777 | 782 | 784 | 768 | 769 | 767 | 765 | 766 | 626 | 710 | 706 | 295 | 444 | 484 | 450 | 463 | 462 | 651 | 652 | 654 | 655 | 642 | 643 | 646 | 647 | 648 | 649 | 650 | 630 | 631 | 632 | 634 | 635 | 636 | 638 | 639 | 640 | 564 | 578 | 582 | 583 | 584 | 587 | 588 | 590 | 591 | 592 | 593 | 594 | 595 | 596 | 597 | 598 | 599 | 600 | 601 | 602 | 603 | 604 | 605 | 606 | 607 | 608 | 609 | 610 | 611 | 613 | 614 | 615 | 616 | 617 | 618 | 619 | 620 | 623 | 437 | 438 | 442 | 443 | 447 | 448 | 455 | 460 | 465 | 466 | 481 | 482 | 483 | 576 | 575 | 562 | 532 | 535 | 537 | 539 | 541 | 543 | 545 | 547 | 551 | 553 | 555 | 513 | 514 | 515 | 516 | 517 | 518 | 519 | 520 | 521 | 522 | 523 | 524 | 525 | 526 | 527 | 528 | 530 | 531 | 500 | 501 | 502 | 503 | 504 | 505 | 506 | 507 | 508 | 509 | 511 | 486 | 487 | 488 | 489 | 491 | 492 | 493 | 495 | 496 | 498 | 499 | 458 | 456 | 360 | 294 | 293 | 415 | 416 | 404 | 402 | 398 | 401 | 377 | 378 | 386 | 372 | 369 | 368 | 358 | 344 | 353 | 355 | 321 | 322 | 325 | 319 | 8 | 272 | 33 | 34 | 35 | 296 | 45 | 86 | 106 | 117 | 159 | 212 | 216 | 235

Iron oxide as a debubbling agent at low temperature

These terra cotta clays were bisque fired at cone 04 and glaze fired to 04 using the 04DSDH schedule. The glaze is G1916Q, an expansion-adjustable cone 04 clear. That schedule alone is often enough to get transparent, defect free glazes in many situations. But not in this case. The solution was to add a fining agent. In this case we added 2% red iron oxide (to the top glaze). The particles of iron floating in the melt acted as a congregating points for bubbles, helping them to escape. And we got a bonus: a more interesting aesthetic. We did further tests and determined that a 1% addition also worked, but not as well. And screening out the larger particles slightly degraded the fining performance. So we have settled on 2% iron and screening the glazes to 100 mesh. Although iron works here, it will not always do so in other situations. And, other fining agent agents we have used at cone 6 do not work in this situation (e.g. 2% Zircopax, Alumina).

One glaze is transparent, the other milky because it is filled with micro bubbles.

Links

Glossary Glaze Bubbles
Suspended micro-bubbles in ceramic glazes affect their transparency and depth. Sometimes they add to to aesthetics. Often not. What causes them and what to do to remove them.
Glossary Terra cotta
The term Terra Cotta can refer to a process or a kind of clay. Terra cotta clays are high in iron and available almost everywhere. While they vitrify at low temperatures, they are typically fired much lower than that and covered with colorful glazes.
Glossary Transparent Glazes
Every glossy ceramic glaze is actually a base transparent with added opacifiers and colorants. So understand how to make a good transparent, then build other glazes on it.
Glossary Drop-and-Soak Firing
A kiln firing schedule where temperature is eased to the top, then dropped quickly and held at a temperature 100-200F lower.

Tell Us How to Improve This Page

Version: Oct/2020

Or ask a question and we will alter this page to better answer it.

Email Address

Name

Subject

Message


Upload picture

Please check recaptcha to proceed


Copyright 2008, 2015, 2017 https://digitalfire.com, All Rights Reserved