Loctite 549

Overview

Loctite 549 is an orange, one-part, anaerobic flange sealant used to create formed-in-place gaskets on rigid metal flanges. It is a gel-like, medium-viscosity, medium-strength product that cures at room temperature when trapped between metal faces, sealing machining marks and surface imperfections.

It delivers an instant low-pressure seal after assembly, then builds full strength over time, helping prevent leaks in pumps, gearboxes and housings.

Key Features & Benefits

One-part gel, ready to use – No mixing; easy bead control on vertical flanges.
Medium strength, medium viscosity – Good gap-filling for close-fitting metal flanges.
Formed-in-place gasket – Replaces many cut paper or cork gaskets, reducing inventory.
Instant low-pressure seal – Helps prevent “weeping” immediately after assembly.

Typical Applications

Flange sealing on pumps, compressors and thermostats
Transmission housings, axle covers and similar rigid metal casings

How to Use

Clean both flanges; remove old gasket material.
Apply a continuous bead of Loctite 549 around the sealing face, circling bolt holes.
Assemble and torque bolts in a cross pattern.
Expect instant low-pressure sealing; allow up to 72 hours at room temperature for full cure.

FAQs

Q1: Can Loctite 549 fully replace a cut gasket?
Yes, on rigid metal flanges it is designed to work as a formed-in-place gasket, replacing many conventional gaskets.

Q2: What if the flanges are slightly warped?
It will fill minor machining marks and small gaps; severely warped flanges should be repaired or replaced.

Q3: Is Loctite 549 removable?
Yes. Joints can usually be disassembled with normal tools. Cured product is scraped or brushed off during service.

Q4: Can I use Loctite 549 on plastic housings?
No. It is intended for metal-to-metal flanges. For plastics, use a compatible flange sealant.

Q5: When can the assembly see full pressure?
For maximum pressure and fluid resistance, allow cure per TDS (often up to 72 hours at ambient conditions).