2.1.6
Tin-Lead Solder
ASTM B 32, alloy grade 50B for temperatures up to 65 degrees C 150 degrees F
and alloy grade 95TA for temperatures over 65 degrees C 150 degrees F.
2.1.7
Silver Solder
AWS A5.8, 15 percent silver base brazing alloy, melting point not less than
540 degrees C 1000 degrees F.
2.1.8
Laminated Plastic
NEMA LD 3 and NSF 35.
2.2
FABRICATION
Fabricate Custom fabricated and commercial equipment in accord with NSF 2.
2.2.1
Welding
Provide at sink inserts, where sheet size necessitates a joint, and at
joints of hoods. Make welds watertight.
2.2.1.1
Welds
Use tungsten inert gas process. Use filler metal compatible with the
material being welded. Do not use carbon arc welding on tops of counters,
tables, drainboards, exposed shelving, or sinks. Make welds ductile and of
same color as adjoining surfaces.
2.2.1.2
Joints
Penetrate entire thickness for the entire length of the joint; make joints
flat, continuous and homogeneous with the sheet metal without reliance on
straps under seams, filling in with solder, or spot welding. When
stainless steel is joined to dissimilar metals, use stainless steel for
fastening devices and welding material.
2.2.1.3
Hidden Surface Welds
Wherever welds occur on surfaces not finished by grinding or polishing,
coat such welds and the accompanying discoloration in the factory with a
metallic-based paint in such a manner as to prevent the possibility of
progressive corrosion of such joints.
2.2.1.4
Grinding, Polishing, and Finishing
Grind exposed welded joints flush with the adjoining material and finish
and polish to match the adjoining surface. In grinding avoid excessive
heating of the metal and metal discoloration. Abrasives, wheels, and belts
used in grinding shall be iron-free and shall not have been used on carbon
steel. Grind off excess metal and smooth to a No. 4 finish. Remove
imperfections such as pits, runs, sputter, cracks, low spots, voids and
buckles. Remove the grain of rough grinding by several successively finer
polishing operations until specified finish is attained.
2.2.1.5
Protection Against Corrosion
Wherever a welding operation occurs on stainless steel, the possibility of
SECTION 11400N
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