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|  MIL-E-22200G
Weld pad dimensions.
TABLE I.
4.6.8 Covering moisture. The following method shall be used to determine
moisture content in an electrode covering: Oxygen shall be passed over the
sample of covering in a nickel or clay boat placed in a fused silica or high-
temperature ceramic-type combustion tube which is then heated. Liberated water
shall be collected in a weighted absorption U-tube and weight of water determined
by the increase in the weight of the U-tube. The moisture content shall be
expressed as a percentage of the weight of the covering sample. Electrodes shall
meet the minimum moisture requirements as specified in the detail specification.
4.6.8.1 Apparatus.
The apparatus shall be as shown on figure 2 and shall
consist of the following:
(a)
A tube furnace with a heating element of sufficient length to heat
at least 8 inches of the middle portion of the combustion tube to
(1093 degrees Celsius
(b)
An oxygen purifying train consisting of a needle valve, flow
meter, 96 percent sulfuric acid wash bottle, spray trap, and
anhydrous magnesium perchlorate drying tower.
(c)
Fused silica combustion tube 7/8 inch inside diameter with plain
ends and a devitrification point above
(1093"C).
(A high-
temperature ceramic-type tube can be used, but a higher blank
value will result.) A plug of fine glass wool to filter the
gases shall be inserted far enough into the exit end of the
combustion tube to be heated to a temperature of 400 to
(204 to
(d)
Water absorption train consisting of a U-cube (Schwartz type)
filled with anhydrous magnesium perchlorate and a concentrated
sulfuric acid gas-sealing bottle.
4.6.8.2 Preparation of the sample. The covering sample of at least 4 grams
shall be a composite of the middle portions of covering from three electrodes
from the same package and shall be removed by bending or with clean, dry forceps.
The sample shall be transferred immediately to a dried, stoppered vial or sample
bottle.
15
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