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6. Application Hints
As with all adhesives, performance depends on conditions of use. Suggestions or
recommendations contained herein are for guidance only, since actual conditions of
use are outside the supplier’s control.
• Ensure that the surfaces to be bonded are dry, free from dust, grease, and
loose particles.
• Apply adhesive to one surface only. Bring the two surfaces together as
quickly as possible; the faster the bond is made, the greater the strength.
• A heavier spray pattern increases both working time and bond strength.
• When gluing dissimilar materials, apply the adhesive to the least heat
conductive of the two.
• On materials that are cold to the touch, a better bond can be made by pre-
warming them before applying adhesive.
• Surplus adhesive can be trimmed using a sharp knife once it has cooled.
Should molten adhesive drip onto a smooth or polished surface, allow it to cool
completely before removal.
• Spray adhesives can be applied directly to expanded polystyrene and other
plastic foams.
• Use only genuine Loctite
®
Hysol
®
adhesives to ensure reliable performance.
Loctite
®
Hysol
®
adhesives are non-toxic and non-flammable.
7. Troubleshooting
Before proceeding with any repair or maintenance operation disconnect the tool
from the mains electricity supply.
Glue “Backup” and “Meltdown”
“Backup” occurs when hot molten adhesive in the glue chamber is forced back
between the barrel wall and the outside surface of the adhesive cartridge and piston.
Once this adhesive cools, it may lock the adhesive cartridge in the barrel, preventing,
or at least restricting, normal extrusion. By far the most likely cause of backup is
allowing insufficient warm-up time before operating the tool (the molten glue in the glue
chamber cannot escape forwards because the nozzle is blocked, due to being
insufficiently warm). In the vast majority of cases the backup self-clears once the tool,
having fully reached operating temperature, is operated again. For the rare occasions
where the backup does not self-clear, turn the spray air adjuster fully clockwise; this
will switch off the spray air, allowing the full pneumatic line pressure to be applied to
the piston (the tool will operate as a bead tool).
"Meltdown" occurs when the rear of the adhesive cartridge softens to the extent that it
is not rigid enough to drive the cartridge forward without collapsing. As with backup,
the molten adhesive can solidify, potentially locking the cartridge and / or piston into
the barrel. Meltdown is caused by leaving the tool switched on for extended periods of
time without operating it. It is recommended that, if the tool is to be left standing for
forty minutes or more, it should be switched off and only switched back on when
preparing to use it again.
The Loctite
®
Hysol
®
175-SPRAY and 175-SPRAY-HT tools are fitted with specially
coated pistons which have non-stick characteristics far superior to any PTFE coating;
this minimises the effect of any backup or meltdown, should it occur.