Loctite AA 324

Overview

Loctite AA 324 (Loctite 324 Speedbonder) is a one-part, urethane methacrylate acrylic structural adhesive designed for bonding flat parts and dissimilar materials. It is supplied as a transparent / light amber, medium-to-high viscosity liquid that cures at room temperature when used with an activator such as Loctite 7075.

Once confined between close-fitting parts and activated, AA 324 develops tough, impact-resistant bonds ideal for:

• Metal-to-metal joints

• Ferrite to plated steel in electric motors and loudspeaker hardware

• Other dissimilar rigid substrates

Typical performance data (approximate):

• Chemistry: Urethane methacrylate ester acrylic

• Viscosity: ~10,000–24,000 mPa·s (cP)

• Fixture time: ≈ 5 minutes with activator, at room temperature

• Full cure: ~24 hours (up to 72 h depending on substrate and gap)

• Shear strength: ≈ 2,700 psi (18–19 MPa)

• Tensile strength: ≈ 4,900 psi (34 MPa)

• Peel strength: ≈ 13 pli

• Max service temperature: up to about +177 °C / 350 °F

Key Features & Benefits

• High impact and toughness
  Formulated to deliver excellent impact and peel resistance, so joints survive shock, vibration and handling abuse.

• No-mix, activator-cure system
  AA 324 is a single-component liquid cured by a separate activator (e.g. Loctite 7075), eliminating in-nozzle mixing and ratio errors.

• Fast fixture with structural strength
  Offers epoxy-like strength with “instant” fixturing in roughly 5 minutes, supporting efficient production lines.

• Multi-surface capability
  Bonds metals, ferrites and other rigid substrates, especially dissimilar materials in compact assemblies.

• Solvent-resistant & durable
  Cured adhesive is resistant to many solvents and designed for long-term structural performance in industrial environments.

• Medium–high viscosity
  Viscosity in the 10,000–24,000 cP range allows good wet-out while staying in place on vertical and overhead joints.

Typical Applications

Loctite AA 324 is widely used as a general-purpose structural bonder for:

• Electric motors

  • Bonding ferrite magnets to plated steel housings or rotors

  • Fixing flat metal or ferrite components in compact motor assemblies

• Loudspeaker and audio hardware

  • Joining magnets to top plates and pole pieces

  • Bonding flat metal components in speaker structures

• Metal fabrication & general industry

  • Structural metal-to-metal bonding where welding or mechanical fasteners are impractical

  • Joining dissimilar materials in fixtures, brackets, housings and small frames

• Repair and retrofit work

  • High-strength bonding or re-bonding of flat plates, stiffeners and inserts without heat input.

How to Use Loctite AA 324

Always follow the latest Henkel TDS and your in-house process instructions. Steps below are a practical guide.

Step 1 – Surface preparation

1. Remove oil, grease, dust and loose oxides from all bonding areas.

2. Clean with a suitable solvent-based cleaner and allow to dry.

3. For critical joints, light abrasion on metals or ferrites, followed by re-cleaning, usually improves strength.

Step 2 – Apply activator

1. Apply Loctite 7075 (or specified activator) to one of the mating surfaces in a thin, even film.

2. Allow the activator to flash off and dry (surface should look dry, not wet) as per TDS recommendations.

Step 3 – Apply adhesive

1. Apply Loctite AA 324 to the other surface as a continuous bead or thin layer.

2. Cover the intended bond area adequately; avoid entrapping air but don’t flood the joint.

Step 4 – Assemble & fixture

1. Bring parts together promptly after application, align accurately and apply firm contact pressure.

2. Maintain light clamping or fixturing until handling strength is reached – typically around 5 minutes at room temperature, depending on substrates, gap and temperature.

Step 5 – Full cure

1. Assemblies can often be moved carefully after fixturing, but avoid full mechanical or thermal load until the adhesive is fully cured.

2. Full cure is typically 24 hours at ~23 °C, and may extend up to 72 hours for wider gaps or less active substrates.

Safety & Handling

• AA 324 is a methacrylate-based acrylic adhesive; it can cause skin and eye irritation and may cause sensitisation with repeated exposure.

• Use in a well-ventilated area; avoid breathing vapors, especially during production.

• Wear safety glasses, chemical-resistant gloves and suitable protective clothing.

• Keep away from heat, sparks and open flames; follow Henkel’s storage temperature guidance.

• Prevent uncured adhesive and activator from entering drains or waterways; dispose of waste according to local regulations.

Always consult the latest SDS and TDS before use.

FAQs

Q1: What is Loctite AA 324 mainly used for?
Loctite AA 324 is mainly used as a high-impact structural acrylic for bonding flat parts and dissimilar materials, especially ferrites to plated metals in electric motors and loudspeakers, and for metal-to-metal structural joints.

Q2: Is AA 324 a one-part or two-part system?
The adhesive itself is one-part, but it works as a two-step system: you apply a separate activator (e.g. 7075) to one surface and AA 324 to the other, then assemble. There is no mixing of resin and hardener.

Q3: How fast does it reach handling strength?
With the recommended activator and good joint design, fixture is typically achieved in about 5 minutes at room temperature, giving a good balance of working time and throughput.

Q4: What materials does Loctite AA 324 bond best?
It is optimized for metals and ferrites, and is particularly effective for ferrite-to-plated metal joints. It also works on other rigid substrates used in structural and motor assemblies.

Q5: Is AA 324 suitable for large gap bonding?
Yes, when combined with Loctite 7075 activator, AA 324 is described as ideal for large gap applications compared to many standard CAs or anaerobics, but extremely wide or highly flexible joints may still require a different adhesive type.

Q6: How temperature-resistant is the cured adhesive?
Data from distributors show maximum service temperatures around +177 °C (350 °F), but actual limits depend on load, environment and joint design. For continuous high-temperature service, always check the TDS and test your application.

Q7: Can I disassemble parts bonded with AA 324?
AA 324 is a structural adhesive; bonds are generally considered permanent. Disassembly usually requires mechanical methods (and sometimes heat) and may damage one or both components, so joints should be designed assuming limited rework.