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ADHESIVE

Silicon Sealent

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Silicone sealants are versatile, liquid adhesives that cure into a flexible, rubber-like solid. In industrial settings, they are primarily used for gasketing, sealing joints, and providing a weather-resistant barrier due to their excellent stability across wide temperature ranges.

Key Technical Specifications

The performance of a silicone sealant is defined by its chemical curing system and its physical properties once fully cured.

1. Curing Systems

  • Acetoxy Cure: Releases acetic acid (smells like vinegar) as it cures. It is fast-curing and adheres well to glass and non-porous surfaces but can corrode sensitive metals like copper or brass.

  • Neutral Cure (Alkoxy or Oxime): Releases a non-acidic byproduct. It is safe for use on metals, plastics, and masonry and offers superior adhesion for industrial piping and electronic housings.

2. Physical Properties

  • Temperature Resistance: Standard silicones typically handle -50°C to +200°C. High-temperature versions (often red in color) can withstand up to 300°C+.

  • Elongation at Break: This measures flexibility. High-quality industrial silicones often have an elongation of 400% to 600%, allowing them to stretch without tearing.

  • Tensile Strength: Typically ranges from 1.5 to 2.5 MPa, providing a durable bond that resists mechanical stress.

  • Shore A Hardness: Measures the "stiffness" of the cured rubber. Most sealants fall between 25 and 40 Shore A.

3. Application Performance

  • Skin-over Time: The time it takes for the surface to become non-tacky (usually 5–20 minutes).

  • Cure Rate: Typically 2mm to 3mm per 24 hours at room temperature and 50% humidity.

  • Dielectric Strength: Silicones are excellent insulators, often rated around 15–20 kV/mm, making them ideal for sealing electrical junction boxes.

Comparison of Industrial Sealant Types

Feature
General Purpose Silicone
High-Temp (RTV) Silicone
Neutral Cure Silicone
Typical Color

Clear, White, Black

Red, Grey

Clear, Black, Grey

Temp Range

-50°C to 200°C

-60°C to 315°C

-50°C to 150°C

Corrosion Risk

High (on metals)

Low

None

Common Use

Glass, ceramics, DIY

Engine gaskets, ovens

Metal roofs, PVC, Electronics

Industrial Applications

  • Pneumatic Systems: Sealing around manifold housings and port connections where vibration is present.

  • Pipe Fitting: Used as a flexible gasket maker for non-pressurized flange connections or as a secondary weather seal.

  • Maintenance (RTV): "Room Temperature Vulcanizing" (RTV) silicones are used to create "formed-in-place" gaskets for gearboxes and pumps.

Proper Application Steps

  1. Clean: Remove all old sealant, oil, and moisture.

  2. Prime: Some substrates (like certain plastics) require a primer for maximum adhesion.

  3. Apply: Cut the nozzle at a 45° angle to the desired bead size.

  4. Tooling: Smooth the bead within the skin-over time to ensure a proper seal against the edges.

Loctite

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Loctite is the global leader in anaerobic adhesives, specifically known for Threadlockers, Thread Sealants, and Retaining Compounds. In industrial piping and pneumatic systems, Loctite is essential for preventing fastener loosening due to vibration and ensuring leak-proof connections.

1. Loctite Threadlockers (The "Big Three")

Threadlockers are categorized by their strength and the size of the fastener they are designed for. They cure in the absence of air between metal surfaces.

Type
Color
Strength
Technical Specifications
Best Use
Loctite 222

Purple

Low

Torque: 6 Nm; Temp: -54°C to 150°C

Small screws (< M6), adjustment screws.

Loctite 243

Blue

Medium

Torque: 26 Nm; Temp: -54°C to 180°C

General Purpose. Removable with hand tools.

Loctite 271

Red

High

Torque: 33 Nm; Temp: -54°C to 180°C

Permanent assembly. Requires heat (250°C) to remove.

2. Loctite Thread Sealants (For Pipes)

Unlike standard Teflon tape, these liquid sealants provide 100% sealing and won't shred or clog pneumatic valves.

  • Loctite 567: High-temperature sealant for coarse threads (up to 250°C). Excellent for stainless steel.

  • Loctite 577: Medium-strength, general-purpose sealant for all metal threads.

    • Max Pressure: Up to 10,000 PSI when fully cured.

    • Viscosity: High (Thixotropic), meaning it won't run or drip during application.

3. Key Technical Performance Metrics

  • Fixture Time: The time it takes to hold the parts in place (typically 5–20 minutes depending on the metal type).

  • Full Cure Time: Usually 24 hours to reach maximum pressure and vibration resistance.

  • Breakaway Torque: The force required to start the movement of a nut or bolt.

  • Prevailing Torque: The force required to continue turning the fastener after the initial "break."

  • Oil Tolerance: Modern formulas (like 243 and 263) are designed to work effectively even on surfaces that haven't been perfectly degreased.

4. Application Guide for Industrial Use

  1. Clean: For best results, clean threads with a primer (like Loctite SF 7471) or a degreaser.

  2. Apply: Apply the liquid to the leading threads of the male fitting.

  3. Assemble: Tighten the assembly to the required torque.

  4. Wait: Allow sufficient fixture time before subjecting the system to pressure.

Anabond

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Anabond is one of India's leading manufacturers of engineering adhesives and sealants, widely used in industrial maintenance, automotive assembly, and pneumatic systems. They specialize in anaerobic adhesives (similar to Loctite) and RTV silicone sealants.

1. Anabond Anaerobic Threadlockers

These are used to lock and seal threaded fasteners, preventing loosening due to vibration and leakage through the threads.

Product
Color
Strength
Technical Specifications
Primary Use
Anabond 111

Purple

Low

Viscosity: 800–1200 cP; Temp: -50°C to 150°C

Small fasteners, adjustment screws.

Anabond 112

Blue

Medium

Breakaway Torque: 12–25 Nm; Temp: up to 150°C

General machine bolts, removable.

Anabond 113

Red

High

Breakaway Torque: 25–40 Nm; Permanent bond

Heavy-duty studs, engine mounts.

2. Anabond RTV Silicone Sealants (Gasket Makers)

"RTV" stands for Room Temperature Vulcanizing. These silicones are highly effective for sealing flanges and valve housings.

  • Anabond 666 (Clear/White/Black): * Type: Acetoxy cure.

    • Temp Resistance: -50°C to 200°C.

    • Specs: Tensile strength of 2.0 MPa; Elongation ~400%.

    • Use: General purpose sealing in non-corrosive environments.

  • Anabond 673 (Red):

    • Type: High-Temperature resistant.

    • Temp Resistance: Up to 300°C (intermittent).

    • Use: Ideal for high-heat industrial machinery and steam pipe insulation.

3. Anabond Pipe Sealants

Specifically designed for threaded pipe joints in pneumatic and hydraulic systems.

  • Anabond 411: A medium-strength pipe sealant with PTFE.

    • Technical Specs: Instant seal up to 5 bar; Full seal up to 350 bar (after 24 hours).

    • Advantage: It does not shred like Teflon tape, preventing the clogging of sensitive pneumatic solenoid valves.

4. Technical Performance Characteristics

  • Cure Speed: Anaerobic products (Threadlockers) achieve fixture strength in 15–30 minutes on steel but require longer for plated or inactive metals (like Stainless Steel).

  • Gap Filling: Capable of filling gaps from 0.05 mm to 0.50 mm depending on the viscosity of the specific grade.

  • Chemical Resistance: Once cured, Anabond products are highly resistant to water, industrial oils, glycol, and various gases used in pneumatic lines.

Maintenance Tip for Your Work:

When using Anabond on Stainless Steel (SS) pipes or fittings, the cure time will be slower than on Mild Steel (MS). Using an Anabond Activator can speed up the bonding process in these cases.

Fevicol

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Fevicol, manufactured by Pidilite Industries, is the most iconic brand of PVA (Polyvinyl Acetate) adhesives in India. While it is synonymous with woodworking, Fevicol has expanded into a vast range of industrial adhesives used for laminates, flooring, and specialized bonding in manufacturing.

1. Fevicol SH (Strategic Household)

This is the flagship product, known for its "Elephant" logo. It is a synthetic resin adhesive used primarily for bonding wood, plywood, laminates, and veneers.

  • Appearance: White viscous paste.

  • Viscosity: 200–300 Poise (very thick, non-drip).

  • pH Value: 4.0 to 6.0.

  • Bond Strength: Minimum 280 kg/cm² (on wood-to-wood joints).

  • Cure Time: 24 hours for full strength; 6–8 hours for handling strength.

2. Specialized Industrial Variants

Variant
Key Technical Feature
Best Application
Fevicol Marine

72-hour boiling water resistance

Kitchen cabinets and areas exposed to water.

Fevicol HeatX

Heat resistance up to 170°C

Bonding laminates on surfaces exposed to sunlight or heat.

Fevicol Speedx

Rapid set (2-hour pressure time)

High-speed assembly lines and quick repairs.

Fevicol Hi-Per

High coverage and bubble-free

Vertical lamination and large surface areas.

3. Key Technical Specifications

  • Solid Content: Usually ranges between 35% and 55% depending on the grade. Higher solid content typically means a stronger, faster-setting bond.

  • Spreadability: Approximately 8 to 10 square feet per kg (depending on surface porosity).

  • Shelf Life: 12 to 18 months when stored in a cool, dry place in its original sealed container.

  • Water Resistance: Standard Fevicol SH is not waterproof; however, variants like Marine and D3/D4 rated adhesives offer significant moisture resistance.

4. Application Process

  1. Surface Prep: Surfaces must be clean, dry, and free of oil or grease. For smooth laminates, slight roughening with sandpaper improves the bond.

  2. Application: Apply a uniform thin layer on both surfaces using a brush or spreader.

  3. Clamping: Pressure is essential. Use clamps, weights, or masking tape to keep the surfaces in tight contact for at least 4–6 hours.

  4. Cleaning: Excess wet adhesive can be cleaned with a damp cloth. Once cured, it must be removed mechanically (sanding or scraping).

Important Note for Your Industrial Work:

While Fevicol is excellent for wood and laminates, it is not suitable for bonding metal pipes or pneumatic fittings. For those, the anaerobic adhesives like Anabond or Loctite (which we discussed earlier) are the correct technical choice.

Devcon Metal Putties

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Devcon Metal Putties, specifically the Plastic Steel Putty (A), are steel-filled epoxy compounds used for heavy-duty industrial repairs. Often called "cold welding," these putties allow you to repair pipes, valves, and machinery without the heat of a welding torch, making them ideal for environments where traditional welding is dangerous or impractical.

1. Devcon Plastic Steel Putty (A)

This is the most common variant used for patching and repairing areas where a high-strength, steel-like finish is required.

  • Type: Two-part Epoxy (Resin + Hardener).

  • Mixing Ratio: 9:1 by weight (or 2.5:1 by volume).

  • Color: Grey (Steel-like finish).

2. Key Technical Specifications

Property
Value / Specification
Compressive Strength

8,260 PSI ($57 \text{ MPa}$)

Adhesive Tensile Shear

2,730 PSI ($18.8 \text{ MPa}$)

Max Temperature Resistance

Wet: 50°C; Dry: 121°C

Hardness (Shore D)

85 (Extremely rigid)

Pot Life @ 24°C

45 Minutes (Time you have to apply it)

Full Cure Time

16 Hours

Shrinkage

0.0006 in/in (Negligible)

3. Common Industrial Applications

  • Pipe Repair: Patching holes and leaks in MS/SS pipes and elbows.

  • Valve Housings: Repairing pitted or corroded valve bodies and pump casings.

  • Stripped Threads: Filling oversized or stripped holes and re-tapping them.

  • Flange Resurfacing: Repairing worn flange faces to ensure a proper gasket seal.

4. Application Steps

  1. Surface Preparation: This is the most critical step. The surface must be thoroughly degreased and grit-blasted or sanded with coarse sandpaper (80 grit) to a "near-white metal" finish for maximum adhesion.

  2. Mixing: Mix the resin and hardener on a flat surface until the color is a uniform, streak-free grey.

  3. Application: Spread the putty firmly onto the repair area to ensure it "wets" the surface and fills all voids.

  4. Machining: Once fully cured (16 hours), Devcon can be drilled, tapped, turned, or sanded just like actual steel.

5. Other Devcon Variants

  • Devcon Titanium Putty: For high-precision repairs and better chemical resistance.

  • Devcon Aluminum Putty (F): For repairing aluminum castings and components.

  • Devcon Wear Resistant Putty (WR-2): For surfaces subject to heavy friction and sliding wear.

Insulation Tape

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Insulation tape, commonly known as electrical tape, is a pressure-sensitive tape used to insulate electrical wires and other materials that conduct electricity. While most often made of PVC (polyvinyl chloride), it is engineered to be flexible, stretchable, and resistant to environmental factors like moisture and heat.

Key Technical Specifications

For industrial and professional use, insulation tape must adhere to standards such as ASTM D1000 or IEC 60454 to ensure safety and reliability.

1. Dielectric Strength

This is the most critical safety metric. It represents the maximum voltage the tape can withstand before breaking down.

  • Standard Rating: Typically 600V to 1,000V for a single layer.

  • Dielectric Breakdown: Usually rated around 40 kV/mm to 50 kV/mm.

2. Temperature Resistance

  • Operating Range: High-quality industrial tapes are rated from -10°C to 80°C (176°F).

  • Flame Retardancy: Professional tapes are designed to be self-extinguishing and will not support a flame.

3. Mechanical Properties

  • Elongation: This is the tape's ability to stretch before breaking. A good tape has an elongation of 150% to 250%, allowing it to wrap tightly around irregular joints and splices.

  • Adhesion to Steel: Measures how well the adhesive sticks. Standard ratings are around 1.8 N/cm to 2.5 N/cm.

  • Tensile Strength: Usually around 20 N/cm to 30 N/cm, providing enough strength to wrap tightly without snapping.

Common Types of Insulation Tape

Tape Material
Primary Use Case
Key Advantage
PVC (Standard)

General electrical wiring

High flexibility and moisture resistance.

Rubber (Self-Amalgamating)

High-voltage splices & waterproofing

Fuses to itself to create a solid, watertight mass.

Glass Cloth

High-heat environments

Heat resistant up to 150°C+; very high tensile strength.

Vinyl (Premium)

Color coding & harsh weather

Better UV resistance and cold-weather performance.

Color Coding Standards (Industrial)

In many regions, tape colors are used to identify phase and voltage in electrical systems:

  • Black: Low voltage / general insulation.

  • Red / Blue / Yellow: Phase identification in 3-phase systems.

  • Green or Green/Yellow: Grounding/Earth wires.

Application Best Practices

  1. Stretch while wrapping: To ensure a tight, moisture-proof seal, stretch the tape to about 75% of its maximum elongation as you wrap.

  2. Half-Lap Technique: Each turn of the tape should overlap the previous turn by 50%. This ensures double insulation at every point.

  3. Final Wrap: The last turn should be applied with zero tension to prevent the ends from "flagging" or peeling back over time.

BOPP (Biaxially Oriented Polypropylene)  Tape

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BOPP (Biaxially Oriented Polypropylene) film coated with a pressure-sensitive adhesive. While they share similar materials, their thickness, adhesive strength, and applications differ significantly.

1. Brown Tape (Packaging Tape)

Brown tape is engineered for heavy-duty sealing, specifically for corrugated boxes and industrial packaging. The brown color is usually achieved through the adhesive or a pigment in the film.

Technical Specifications:

  • Film Material: BOPP (Biaxially Oriented Polypropylene).

  • Adhesive Type: Water-based Acrylic or Hot-melt Rubber.

  • Total Thickness: 40 to 55 microns (higher microns mean a stronger tape).

  • Width: Standard widths are 48mm (2 inches) and 72mm (3 inches).

  • Tensile Strength: High (approx. 35–45 N/cm), designed to hold heavy box flaps under tension.

  • Elongation: Around 100% to 150% before breaking.

2. Cello Tape (Transparent / Stationary Tape)

Cello tape is a general-purpose clear tape used for lighter tasks, office work, and small parcel sealing. It is designed to be as invisible as possible once applied.

Technical Specifications:

  • Film Material: BOPP or Cellulose (original "Cellophane").

  • Adhesive Type: Acrylic Emulsion.

  • Total Thickness: Typically thinner than brown tape, ranging from 30 to 40 microns.

  • Width: Common sizes include 12mm, 18mm, and 24mm (1 inch).

  • Clarity: High transparency; high-quality variants are designed not to yellow over time.

  • Adhesion Strength: Lower than brown tape, optimized for paper, plastic, and light cardboard.

Technical Comparison Table

Feature
Brown Packing Tape
Transparent Cello Tape
Primary Use

Heavy Carton Sealing

Stationary, Crafts, Light Packing

Common Thickness

45–50 Microns

35–40 Microns

Adhesive Grip

High (Aggressive)

Moderate (Removable from some surfaces)

Standard Roll Length

50m, 65m, or 100m

10m to 30m (Office), 65m (Industrial)

UV Resistance

Moderate

High (Designed to stay clear)

Industrial Application Tips

  • Temperature Matters: Acrylic adhesive tapes work best at room temperature but may lose grip in extreme cold. For cold storage or refrigerated environments, Hot-melt or Rubber-based brown tape is required.

  • Surface Preparation: For the best bond on industrial packages, ensure the surface is free of dust and moisture.

  • Pressure: As these are "pressure-sensitive" tapes, always rub the tape firmly after application to "activate" the adhesive bond with the surface.

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