How does Loctite AA 3921 LC cure?

This acrylic adhesive cures rapidly under UV and visible light, with a fixture time starting from 3 seconds.

Which materials can you bond with this adhesive?

It is formulated for stress-sensitive plastics and also bonds metals, glass, and ceramics.

Does this adhesive provide a flexible bond?

Yes, it is specially formulated to deliver flexible and high-strength bonds.

What is the volume of this syringe?

This syringe contains a net volume of 25 ml.

Can you inspect the adhesive after dispensing?

Yes, it fluoresces under UV light to allow easy visual quality inspection.

LOCTITE 3921 light-curing adhesive for flexible bonding of stress-sensitive plastics (25 ml syringe) - 1173686

Name: LOCTITE 3921 light-curing adhesive for flexible bonding of stress-sensitive plastics (25 ml syringe) - 1173686
Brand: LOCTITE
SKU: 03245891
Price: 83.49 EUR
Availability: PreOrder

Supplier number: LOCTITE 1173686 | EAN

From 1 piece €83.49

From 5 pieces €79.32 - €20.87 saving

From 10 pieces €77.23 - €62.62 saving

From 15 pieces €75.14 - €125.24 saving

83.49 tax incl.

€69.00 excl. VAT (incl. all environmental contributions)

On order: delivered from 26/10/2026

Delivery by DHL

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How does it work?

For a purchase value of €99 to €125 excl. VAT, receive FREE LOCTITE 55 thread sealing cord 50 m (IDH 528244) worth €9.99.
For a purchase value of more than €125 excl. VAT, receive FREE LOCTITE SF 7850 hand cleaner 400 ml (IDH 2098250) worth €13.21.
The free item is automatically added to your order. No registration is required.
The promotion is valid from 01.10.2026 to 31.10.2026.
Loctite Buy & Get deals are recognisable by the promotion label on the product page. Click the label to view all available deals.

Fast precision bonding with Loctite

Practical benefits

Rapid light curing action: You speed up assembly workflows significantly with a fast fixture time of just 3 seconds.
Flexible stress crack protection: You securely bond stress-sensitive plastics and metals while maintaining joint flexibility to prevent material damage.
Clean and accurate dispensing: The low viscosity liquid and convenient 25 ml syringe format allow you to apply adhesive with exact precision.

In a nutshell

The right choise for

With Loctite aa 3921 LC, you bond stress-sensitive plastics, metals, glass, and ceramics with exceptional precision and reliability. This liquid acrylic adhesive cures rapidly under uv and visible light, achieving a fixture time in just 3 seconds to keep your assembly workflow moving fast. The flexible bond prevents stress cracking in sensitive thermoplastics while maintaining high joint strength. Thanks to the low viscosity and convenient 25 ml syringe format, you dispense cleanly and accurately every time. In addition, the adhesive fluoresces under uv light for quick and dependable visual quality inspection.

Product information FAQ

€83.49

tax incl.

Key features according to our expert

Net volume: 25 ml
Relative density: 1,129
ADR packing group: III
ADR class: 9
Principal hazard property: GHS05 Corrosive
UN number: UN3082
P-statements: P201; P273; P280; P305 + P351 + P338; P308 + P313; P333 + P313
H-statements: H302; H317; H318; H360F; H400; H410
Hazard class: GHS05 Corrosive; GHS07 Harmful or irritant; GHS08 Health hazard; GHS09 Environmental hazard
Physical state: Liquid
Flash point: 85 °C
Packaging: Bottle

Product description:

LOCTITE AA 3921 LC

Characteristics:

LOCTITE AA 3921 is a light-curing, acrylic-based adhesive for flexible bonding for stress-sensitive plastics.
The product offers a curing depth of > 13 mm and a fixing time of barely 3 s
Complies with ISO 10993 for applications with medical devices, e.g. for bonding stainless steel cannulas in hubs, syringes and lancets for needle systems.

Hazard statements

H302: Harmful if swallowed.
H317: May cause an allergic skin reaction.
H318: Causes serious eye damage.
H360F: May damage fertility.
H400: Very toxic to aquatic life.
H410: Very toxic to aquatic life with long lasting effects.

Precautionary statements

P201: Obtain special instructions before use.
P273: Avoid release to the environment.
P280: Wear protective gloves/protective clothing/eye protection/face protection.
P305 + P351 + P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P308 + P313: IF exposed or concerned: Get medical advice/attention.
P333 + P313: If skin irritation or rash occurs: Get medical advice/attention.

All Features

Net volume: 25 ml
Relative density: 1,129
Adr packing group: III
Adr class: 9
Principal hazard property: GHS05 Corrosive
Un number: UN3082
P-statements: P201; P273; P280; P305 + P351 + P338; P308 + P313; P333 + P313
H-statements: H302; H317; H318; H360F; H400; H410
Hazard class: GHS05 Corrosive; GHS07 Harmful or irritant; GHS08 Health hazard; GHS09 Environmental hazard
Physical state: Liquid
Flash point: 85 °C
Packaging: Bottle

Brand LOCTITE
03245891
EAN
Supplier number LOCTITE 1173686

Frequently asked questions about this product

Answered by specialists

How does Loctite AA 3921 LC cure?: This acrylic adhesive cures rapidly under UV and visible light, with a fixture time starting from 3 seconds.
Which materials can you bond with this adhesive?: It is formulated for stress-sensitive plastics and also bonds metals, glass, and ceramics.
Does this adhesive provide a flexible bond?: Yes, it is specially formulated to deliver flexible and high-strength bonds.
What is the volume of this syringe?: This syringe contains a net volume of 25 ml.
Can you inspect the adhesive after dispensing?: Yes, it fluoresces under UV light to allow easy visual quality inspection.