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Technical Data Sheet
External Ammunition Sealant 59521

High Performance Adhesives and Sealants

March 2013

Product Description

Page 1 of 2

Typical Cured Performance

Hernon External Ammunition Sealant 59521 is a single
component U.V. anaerobic sealant. 59521 has a low
viscosity penetrating material capable of bonding and
sealing primers and case mouths in ammunition. It is
specially formulated for pre-assembled components; it
works by capillary action sealing ammunition and
improving bullet pull force. Curing occurs when the
adhesive is applied between mating surfaces. The cured
adhesive is a thermoset plastic suitable for temperatures
up to 400ºF (204ºC), and endures exposure to most
solvents.
Ammunition Sealant 59521 cures quickly at room
temperature without the need for surface activators or heat
to seal primer and case mouth assemblies. Fixturing
strength develops in two to three minutes, Full strength will
be reached in 24 hours. Cure fillets at UV light irradiances
above 60 milliwatts/cm² to insure proper cure.

Product Benefits
• UV fluorescence for in-process inspection
• 100% solid system (no solvents)
• Excellent environmental resistance
• Good gap filling properties
• Excellent Bullet Pull strengths with low Standard
deviation
• UV and anaerobic curing mechanism suitable for metal
parts
• Excellent capillary performance

Typical Properties (Uncured)
Property

Value

Appearance

Blue liquid

Fluorescent

Yes

Specific Gravity

1.03

Viscosity @ 25ºC, cP

5-8

Flash Point

See MSDS

Anaerobic fixture time, brass

2 to 3 minutes

UV tack free time, s

≤3

Property

Value

Handling Time at 23ºC, mins.

< 20

Full Strength, hrs.

24

Temperature range, ºF

-65 to 400

General Information
This product is not recommended for use in pure
oxygen and/or oxygen rich systems and should not
be selected as a sealant for chlorine or other strong
oxidizing materials.
For safe handling information on this product,
consult the Material Safety Data Sheet (MSDS).
Where aqueous washing systems are used to clean the
surfaces before bonding, it is important to check for
compatibility of the washing solution with the adhesive.
In some cases these aqueous washes can affect the
cure and performance of the adhesive.
This product is not normally recommended for use on
plastics (particularly thermoplastic materials where
stress cracking of the plastic could result). It is
recommended to confirm compatibility of the product
with such substrates.

Directions For Use
Shake well before use.
Ammunition Sealant 59521 should be applied in
sufficient quantity to fill the rim around Primer cavities.
Application of Adhesive for Bullet Sealing
1. Ammunition Sealant 59521 is dispensed to the
edge of the case where it penetrates around the joint
in less than 5 seconds. Hernon dispensing equipment
employs a valve fitted with a hypodermic needle that
actually touches the joint; the air actuated valve
controls the adhesive quantity dispensed.
2. Bullets can then be cured with a high intensity UV
lamp (2 to 4 second cure at 365 nm).
3. UV protective glasses and gloves should be worn for
protection against the UV light.
4. A low-powered UV lamp can be used to inspect for
the presence of adhesive.