with soldering acid flux the edges of stainless steel to be pretinned.
Seal the joints in aluminum sheets of one mm 0.040 inch or less in
thickness with specified sealants. Do not solder aluminum.
3.1.8
Welding and Mechanical Fastening
Use welding for aluminum of thickness greater than one mm 0.040 inch.
Aluminum one mm 0.040 inch or less in thickness shall be butted and the
space backed with formed flashing plate; or lock joined, mechanically
fastened, and filled with sealant as recommended by the aluminum
manufacturer.
3.1.8.1
Welding of Aluminum
Use welding of the inert gas, shield-arc type. For procedures, appearance
and quality of welds, and the methods used in correcting welding work,
conform to AWS D1.2.
3.1.8.2
Mechanical Fastening of Aluminum
Use No. 12, aluminum alloy, sheet metal screws or other suitable aluminum
alloy or stainless steel fasteners. Drive fasteners in holes made with a
No. 26 drill in securing side laps, end laps, and flashings. Space
fasteners 300 mm 12 inches maximum on centers. Where end lap fasteners are
required to improve closure, locate the end lap fasteners not more than50 mm
2 inches from the end of the overlapping sheet.
3.1.9
Protection from Contact with Dissimilar Materials
3.1.9.1
Copper or Copper-bearing Alloys
Paint with heavy-bodied bituminous paint surfaces in contact with
dissimilar metal, or separate the surfaces by means of moistureproof
building felts.
3.1.9.2
Aluminum
Aluminum surfaces shall not directly contact other metals except stainless
steel, zinc, or zinc coating. Where aluminum contacts another metal, paint
the dissimilar metal with a primer followed by two coats of aluminum paint.
Where drainage from a dissimilar metal passes over aluminum, paint the
dissimilar metal with a non-lead pigmented paint.
3.1.9.3
Metal Surfaces
Paint surfaces in contact with mortar, concrete, or other masonry materials
with alkali-resistant coatings such as heavy-bodied bituminous paint.
3.1.9.4
Wood or Other Absorptive Materials
Paint surfaces that may become repeatedly wet and in contact with metal
with two coats of aluminum paint or a coat of heavy-bodied bituminous paint.
3.1.10
Expansion and Contraction
Provide expansion and contraction joints at not more than 9750 mm 32 foot
intervals for aluminum and at not more than 12 meter 40 foot intervals for
other metals. Where the distance between the last expansion joint and the
SECTION 07600
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