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Recommendations for Handling & Fabricating MgO Thermocouple Wire
MgO is hygroscopic. ends of individual lengths of bulk material are sealed at the factory to prevent moisture absorption and insulation contamination. Moisture absorption by the insulation is still possible under extremely humid conditions, so material should be stored in a dry area. When lengths are cut from the stock the exposed ends on the remaining bulk material should be resealed. If it is anticipated that moisture penetration has taken place over an extended length of wire it should be discarded. Slight moisture penetration can be remedied by applying heat from a blow torch. start about seven inches from the open end, heat the sheath to cherry redness, work the flame slowly down to and over the open end. Seal the open end when it has cooled to about 180oF Squaring of cut ends is recommended to remove loose insulation and contamination. A 180-grit standing belt can be used to rough square the larger sizes. A fine, clean file should be used to finish dress the end. Care should be used to not exert too much pressure when sanding; excessive heating of the sheath will cause smearing over the insulation. |
Stripping of sheath can readily be done by a hand tool on sizes 1/8 inch and smaller. Larger sizes are conveniently stripped in a lathe with a suitable hand held or lathe mounted tool. An alternative method of stripping on larger material is to make an angular cut through the sheath hammer the cut sheath to loosen the insulation, pull the sheath off of the wires. The MgO remaining on the wire should be removed by sand blasting or wiping with emery cloth. The exposed end of insulation should then be sealed. BarcoPac wire is furnished with a dead soft, bright annealed sheath which allows bending over a mandrel as small as twice the sheath OD without cracking. Process mounting fittings may be brazed to a BARCOPAK sheath. to avoid burning through the sheath. It is not recommended that measuring junctions be fabricated in other than controlled factory conditions. Wires must be cleaned of all loose insulation. No flux should be used. Welding of the protective cap should be done in an inert atmosphere with weld rod of the same material as the sheath. |
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Contact Details | Section 5 | Section 6 | Section 7 | Enquiry |