Samand
44
Adjustment and replacement
Welding galvanised sheet metal
Use a wire brush and hot-air gun to remove any paint
from the surface. A grinding machine can grind away
the galvanised surface and should therefore not be
used.
Important
A zinc surfaced immediately begins to oxidise upon
exposure to the atmosphere. When grinding zinc-
coated sheet down to the bare metal, it is therefore
extremely important to apply primer to the exposed
surface within a few minutes. Use an etching primer.
Use only epoxy primer if the surface is to be filled.
Galvanised sheet metal should be spot-welded.
Carry out welding at a somewhat higher
temperature and pressure than for ordinary cold-
rolled sheet. Apply a zinc-based primer between
the surfaces that are to be welded together.
Use welding rod suitable for galvanised sheet,
and an ordinary controlled atmosphere of mixed
gas type for MIG welding.
Use special filler on galvanised sheet metal with
hardener.
Working on galvanised sheet metal calls for a
higher standard of protective equipment than
ordinary cold-rolled sheet.
All new methods and materials can be used on cold-
rolled sheet.
Primer
Cleaning
It is important that all the sheet metal is cleaned before
applying primer. Remains of welding primer will have a
negative effect on the adhesion of paint, filler and
sealant. Use ?? cleaner or equivalent.
Primer
Apply primer to all the bare metal surfaces that are not
to be filled with plastic filler. Note that the primer must
be completely dry before applying sealant. Use ?? or
equivalent.
Prime with epoxy primer before applying filler to sheet
metal. This will prevent corrosion under the filler.
For painting, see Paint and surface treatment process.
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