Loctite 290

Loctite 290

Strength: Penetration grade, medium to high strength, dismantled with hand tools
Temperature range: 150°C
Maximum bolt size: M6
Packaging: 50 ml/250 ml
Color: Green
Viscosity (cP) at 20 rpm: 40
Thixotropy: No
Breakaway torque/average dismantling torque, M10 steel nuts and bolts (N.m, lb.in): 10/29 N.m ; 90/260 lb.in
Temperature range: -55°C to 150°C (-65°F to 300°F)
Fixture time (min): 20

Overview

Loctite 290 is a green, low-viscosity, medium–high strength, wicking grade threadlocker. It’s designed to lock and seal already assembled metal fasteners by penetrating into the thread gap via capillary action, eliminating the need to disassemble joints just to apply threadlocker.

Once confined between close-fitting metal surfaces and deprived of air, the anaerobic resin cures into a tough plastic that:

  • Prevents loosening from vibration and shock

  • Seals the helix against leakage

  • Helps protect threads against corrosion

Why choose Loctite 290?

1) Ideal for preassembled screws and set screws
Because of its very low viscosity and capillary behavior, Loctite 290 can be applied after the joint is assembled. It wicks along the threads to lock parts such as instrumentation screws, carburetor screws, electrical connectors and set screws where position must be set first, then locked.

2) Medium–high strength for lasting reliability
Loctite 290 sits between medium and high strength. On typical steel fasteners it provides strong resistance to loosening, so assemblies on pumps, gearboxes and presses stay tight under continuous vibration. Disassembly usually requires significant tool force and, on larger fasteners, localized heat.

3) Dual role: threadlocking and porosity sealing
The same wicking behavior that lets 290 move into threads also allows it to seal micro-porosity in welds, castings and powder metal parts, stopping weepage of oils, fuels and coolants through tiny pores.

4) Single-component, clean and easy to use
Loctite 290 is a one-part dimethacrylate ester liquid. No mixing, no ratio errors. It’s simply dispensed from small bottles directly onto the joint.

5) Qualified to demanding specifications
Loctite 290 is tested against MIL-S-46163 wicking-grade requirements and is listed by multiple industrial suppliers as a MIL-SPEC threadlocker for preassembled fasteners.

Typical Applications

Preassembled threaded fasteners

  • Instrumentation screws and small fasteners where position must be set before locking

  • Electrical connectors and terminal screws

  • Carburetor and fuel system screws

  • Set screws and adjustment screws on motors, gearboxes and valves

Porosity sealing

  • Sealing porosity in welds and fabrication repairs

  • Sealing pores in castings and powdered metal components to prevent fluid seepage 

General vibration-resistant threadlocking

  • Preassembled bolts up to about 1/2″ (12 mm) where disassembly to apply threadlocker is not practical

  • Retrofits and maintenance work where you must lock an existing assembly in the field

Loctite 290 works on metal fasteners only; it is not recommended for plastics.

How to Use Loctite 290

Step 1 – Prepare the joint

  • Assemble and torque the fastener to its final position.

  • Clean away heavy grease, dirt, or loose rust from the exposed thread area. The product will tolerate light oil films but performs best on reasonably clean metal.

Step 2 – Apply the threadlocker

  • Shake the bottle briefly.

  • Apply Loctite 290 to the exposed thread area at the joint line.

  • Because of its low viscosity, the product will wick into the thread engagement by capillary action. For larger assemblies, apply around the entire circumference.

Step 3 – Let it penetrate

  • Allow a short time for the adhesive to wick fully into the threads.

  • On deep or tight joints, you may reapply a small amount to ensure full penetration.

Step 4 – Allow cure before full load

  • Loctite 290 typically reaches handling strength within minutes, but full performance may require up to 24–72 hours at room temperature, depending on metal type, clearance and temperature. Plan pressure or functional testing accordingly.

Step 5 – Disassembly (if required)

  • Because 290 is medium–high strength, removal of larger fasteners may require substantial torque or localized heat (e.g., 200–250 °C, only if compatible with the base materials) to soften the adhesive before loosening.

Safety & Handling

According to current SDS documents for Loctite 290 Wicking Grade Threadlocker:

  • Hazards:

    • Causes serious eye irritation (H319)

    • May cause respiratory irritation (H335)

    • Harmful to aquatic life (H402)

  • Prevention:

    • Avoid breathing vapors or mist.

    • Use only outdoors or in a well-ventilated area.

    • Avoid release to the environment.

    • Wear suitable eye/face protection and, where appropriate, gloves.

  • General guidance:

    • Wash hands thoroughly after handling.

    • Store in a cool, dry place in the original container.

    • Do not allow uncured product to enter drains or watercourses.

Always read and follow the latest SDS for your region before use.

FAQs

Q1: When should I choose Loctite 290 instead of Loctite 243 or 271?
Choose Loctite 290 when the assembly is already built and you can’t easily take it apart to apply threadlocker. Its wicking behavior lets you lock and seal preassembled fasteners, especially smaller screws and set screws. Loctite 243 is better for standard assembly on clean, accessible threads; Loctite 271 is for very high-strength permanent locking on larger bolts.

Q2: Is Loctite 290 permanent?
Loctite 290 is rated medium–high strength. On typical steel hardware, removal with hand tools is possible on smaller fasteners, but larger bolts may require significant effort or added heat to break loose. If you know regular disassembly is needed, a lower-strength or medium-strength threadlocker may be a better fit.

Q3: Can I apply Loctite 290 before assembly?
Yes, it will still cure as a low-viscosity threadlocker applied before assembly. However, its main advantage is post-assembly application to pre-torqued fasteners. For standard “before assembly” use on most bolts, products like Loctite 243 or 262 are more commonly selected.

Q4: Does Loctite 290 work on stainless steel and plated parts?
Loctite 290 cures on active metals like carbon steel and on more passive substrates like stainless steel and plated fasteners, but cure can be slower on passive metals. Allow extra cure time or consult Henkel about using a primer/activator if you need rapid strength build-up.

Q5: Can I use Loctite 290 on plastic threads?
No. Loctite 290, like other anaerobic threadlockers, is formulated for metal-to-metal joints. It does not cure properly on plastic and may cause stress cracking on some plastics. For plastic or mixed-material joints, use a product specifically designed for those substrates.

Q6: How do I use Loctite 290 for porosity sealing?
Clean the part, then apply Loctite 290 over the porous area so it can wick into the voids. Wipe off surface excess after penetration, then allow full cure before leak testing. This is commonly done on castings, welds and powdered metal parts that exhibit slight weeping.

Q7: What if my parts are heavily contaminated with oil or anti-seize?
Loctite 290 is low-viscosity but not immune to heavy contamination. Thick oil, grease or anti-seize can prevent proper wetting and cure. For best results, remove heavy contamination by wiping or solvent cleaning, then apply 290 so it can contact clean metal surfaces.

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