BNP
®
65 and 220 SUCTION BLAST CABINETS
Page 5
© 2019 CLEMCO INDUSTRIES CORP.
www.clemcoindustries.com
Manual No. 21309, Rev. J 01/19
1.9
Blasting Media
1.9.1
Always use media specifically manufactured for
blasting and that are compatible with the surface being
blasted. Media produced for other applications may be
inconsistent in size and shape, contain particles that
could jam the media metering valve, or cause irregular
wear. Always obtain the safety data sheet (SDS) for the
blasting media prior to blasting and identify material
being removed by blasting, paying particular attention to
worker health risks and presence of any hazardous/toxic
substances.
Most common reusable media specifically manufactured
for blasting can be used in ZERO cabinets. The listing of
media sizes shown in this section and in Figure 4 are
provided as a guideline only. The guideline is based on
standard 5/32" orifice air jet with 5/16" nozzle and average
conditions with variables such as blast pressure, media-
air mixture, visibility inside the cabinet, humidity, and
reclaimer cleaning rate.
Several variables that affect the reclaimer cleaning rate
include reclaimer size (cfm), contamination of parts
being blasted, media friability, damper setting (static
pressure), and dust-collector filter loading (differential
pressure across the dust filters).
As a rule, larger orifice air jets and nozzles deliver more
media, requiring higher performance from the reclaimer.
When using larger nozzles, the maximum mesh size of
media will be smaller than normally recommended.
Using media finer than those recommended may
decrease visibility and, at some point, carry over to the
dust collector. Media coarser than those recommended
may be too dense for the reclaimer to recover from the
cabinet hopper.
1.9.2 Steel shot and steel grit:
Steel shot S-170 to
S-70 or steel grit 50-mesh to 120-mesh may be used in
BNP Cabinets configured for using steel media.
Using steel media requires a smaller diameter conveying
hose (usually reduced one size from standard) and a 900
cfm or larger reclaimers. Rubber curtains should be used
to protect the cabinet walls from peening, warping, and
rapid wear. For these applications, cabinets can be
ordered with reduced-size flex hose appropriately sized
for steel grit, and with rubber curtains installed. They may
also be field installed later. NOTE: Steel grit or shot is too
heavy to use with cabinets equipped with 300 and 600
cfm reclaimers.
1.9.3 Sand and slag:
Sand and slag media are not
suitable for cabinet use. Sand should NEVER be used
for abrasive blasting because of the respiratory hazards
associated with media containing free silica. Slags are
not recommended because they rapidly break down and
are not recyclable.
1.9.4 Silicon carbide, aluminum oxide, and garnet:
These are the most aggressive of the commonly used
media.
Aggressive media may be used, but the service
life of any components exposed to the media will be
reduced. To avoid unscheduled downtime and maximize
cabinet life, periodically inspect the reclaimer wear plate,
blast hose, and nozzle for wear and replace parts as
needed.
When using aggressive media only occasionally, install
an optional aluminum oxide kit, which includes rubber
curtains for the cabinet interior and a boron carbide-lined
nozzle. When using aggressive media on a regular
basis, install the aluminum oxide kit and a fully rubber-
lined reclaimer. Rubber-lined reclaimers are available as
factory-installed items, or field-installed liners can be
installed later on 600 cfm and 900 cfm reclaimers if they
have removable tops and are designed to accept liners.
Nozzles lined with boron carbide extend nozzle wear life.
Refer to
Section 9.3:
BNP Gun and Feed Assembly
.
1.9.5 Glass bead:
Most beads are treated to ensure
free-flow operation, even in environments of moderately
high humidity. Glass beads subjected to excessive
moisture may be reused only after thoroughly drying and
breaking up of any clumps.
1.9.6 Lightweight and fine-mesh media:
When
using lightweight (such as agricultural) media or fine-
mesh (180-mesh and finer) media, the reclaimer inlet
baffle may need to be removed to retain media and
avoid carryover. On 600 cfm and 900 cfm reclaimer
models with bolt-on removable tops, baffle removal and
replacement is easily accomplished, as explained in
Section 7.10. Reclaimers with welded-on tops require
grinding to remove the baffle, and once it is removed it
cannot be replaced.
1.9.7 Plastic media:
Plastic and similar lightweight
and/or nonaggressive media are generally not
recommended for suction-style cabinets because the
lower blast velocity of suction blasting combined with the
softer and lighter weight media do not provide the media
impact for productive blasting. Best performance from
plastic media is achieved with pressure blasting,
requiring a pressure vessel with a 60-degree conical
bottom. Refer to Clemco’s Aerolyte cabinet line.
1.9.8 Bicarbonate of soda:
Bicarbonate of soda is
not recommended for use in standard cabinets. Bicarb is
a one-use media, which will quickly saturate the filter
cartridge(s). Best performance from bicarb media is
achieved with pressure blasting, requiring a pressure
vessel. Refer to Clemco’s Aerolyte cabinet line for
cabinets that are specifically designed for use with
bicarbonate of soda.
