PAINTING IRON AND STEEL WITH ENAMEL PAINTS
Enamel
paints are available as ordinary enamel and synthetic enamel paints. Ordinary
enamel paints are made from natural resins (solid residue obtained after
distillation of turpentine oil from crude turpentine. Also known as resin).
Synthetic enamel is based on synthetic alkyd resins. Enamel paints are
available in interior and special exterior grades. In buildings, these paints
are used to paint iron and steel products such as iron grills and steel
windows. They are available as ready-mixed paints.
Method
of Painting of iron and steel with enamel paint. The painting should be started
only on clear sunny days. Painting is carried out in the following five
operations:
1. Cleaning
and sandpapering
2. Application
of primer coat
3. Stopping
and filling
4. Application
first undercoat
5. Application
of finishing coats
STEP-1,
the surface is thoroughly cleaned by mechanical means of scraping, brushing
with wire brushes. It is then smoothened with sandpaper.
STEP-2,
the primer coat red oxide zinc chromate primer (IS 104) or preferably red oxide
zinc chromate primer (IS 2074) is applied by brushes. After the first coat has
completely dried, a second primer coat is applied, so that a film fully
covering the metal is obtained. It is important that within the shortest period
after cleaning, the first primer should be applied. This is particularly
important in places with high humidity.
STEP-2: Now
stopping and filling after the primer coat has hardened. We apply the paste
filler coat. For this purpose, we first roughen the primer coat with emery
paper (not sandpaper) without scratching and without damaging the primer coat.
We free the surface from dust. Fill the deep dents with paste filler (as used
in body rebuilding of motor cars) using a good putty knife pressing firmly into
the dents and applying only the optimum pressure. Allow as many layers of paste
filler as needed to get a smooth surface allowing each layer to hard dry. Then
wet rub to a smooth finish using waterproof emery paper 280/320. After the last
coat of paste filler is hard and dry, it is wet rubbed down where necessary. We
then apply a coat of readymade filler (R/M filler) by brush. Allow it to dry
and wet rub to a smooth finish.
STEP-4:
it is to apply the first undercoat by brush with minimum brushmarks. The brush
is held at about 45° to the vertical. Paint is first applied in vertical
strokes until the surface is covered and then is applied crosswise with light
strokes. Finally it is laid off with vertical strokes. This constitutes one
coat.
STEP-5: now apply two finishing coats. The first
finishing coat is applied (by brush or spray) and it is allowed to dry. We then
gently remove the gloss for the entire surface by wet cut with waterproof emery
paper 320/400. After the surface is dry and free from dust, we apply the second
coat.
Notes:
1.
Repainting of old iron surfaces is done first by cleaning the surface with
turpentine oil to remove grease and perspiration of handmarks, etc. The surface
is allowed to dry and then repainted.
2. If
exterior surfaces of iron has developed fungi, it should be removed by
ammoniacal copper solution or 2.5% magnesium silicon fluoride and allowed to
dry (read the article: Guidelines
of home painting)
3. The
covering capacity of enamel paints is 18 to 20 m2/litre per coat.
Must read: Types
of Paint Used in Construction and Its Uses
Must read: Guidelines
of Home Painting
Must read: How
to do whitewashing and colour washing
Must read: How
to Do Painting With Cement Paint
Must read: How
to Do Painting With Dry Distemper
Must read: How to do painting of plastered walls with plastic emulsion paint
Must read: How
to do painting new / old woodwork with synthetic enamel paint
Must read: How to
do polishing wood which has attractive grains?
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