Radleigh
carry out blast cleaning to both
ferrous and non-ferrous fabrications
using chilled iron grit and
aluminium oxide respectively. The
process of blast cleaning is used
for the preparation of the substrate
to remove mill-scale and oxides, and
to provide a key prior to the
application of paint, thermal spray
or galvanizing, where a heavier
deposit of zinc is required. It also
highlights faults in welds, such as
pinholes, that are not visible
before the blast cleaning takes
place.
There are a number of blast cleaning
plants such as automatic for columns
and beams, manual for large and
complex fabrications, tumble
blasters for smaller components and
hand held units for etching glass or
for the spot blasting and removal of
individual coats.
The requirements for blast cleaning
are extensively covered in BS 7079
Parts 0 - 6, together with ISO 8501
- 8504. The detail laid down in
these standards is exhaustive and
includes preparation methods and
grades of preparation which are
depicted by photographic examples
introduced by the Swedish Institute
of Corrosion in SIS 05 5900 and now
incorporated into ISO 8501-1.
Although the blast cleaning of the
steel substrate is clean we take
random checks to ensure that there
is no chemical contamination such as
ferrous salts. These salts can
effect the subsequent adhesion of
the primer coat. We also ensure that
the surface profile is up to
specification by using the services
of independent inspectors as well as
keeping our own readings.
A well applied paint system will
fail if the blast cleaning is
flawed. We take every step to ensure
that we get the preparation right.
