Manufacturing News

Oct
03

Adhesives and Sealants for Maintenance, Repair and Operations

By Hernon Manufacturing
 


When there is a problem in a maintenance area, repair professionals work to solve the problem as quickly as possible to avoid continued damage and extensive downtime. MRO products assist in helping to save time, reduce energy costs and reduce waste. MRO products prevent the equipment failures that can lead to downtime such as vibrational loosening of fasteners, air and hydraulic leaks from threaded fittings and gasket failure. Nearly every part on machines are subject to physical and acoustic vibrations. These components need to be secured from loosening with adhesives and sealants that reduce the potential for catastrophic failure.

Threadlockers

Threaded fasteners are the most prevalent detachable hardware used in machinery design and modern mechanical assemblies. Thus, threadlockers are one of the most important MRO adhesive groups, used on nuts, bolts and threaded parts to prevent loosening from shock and vibration. They also resist water or chemical intrusion and corrosion of components (including galvanic corrosion).Threadlockers can be used on all sizes of fasteners with the caveat that each fastener may have unique stressors requiring a specific thread locking strength or type. 

Industrial threadlockers are typically provided in consistent colors regardless of the manufacturer to quickly convey the threadlocker strength or type. The colors,red, blue, purple and green relay the high, medium, low strength and wicking capabilities respectively. Red color threadlockers offer a high strength bond which is designed for permanent bonding. Threaded assemblies locked with a red threadlocker cannot be disassembled with hand tools and need to be weakened by heating before disassembly using power tools. Blue threadlockers are of medium strength and can be disassembled with hand tools after some exertion. Purple threadlockers are used on low-strength metals such as aluminum and brass where easy disassembly is required. Finally, green threadlockers are utilized to penetrate pre-assembled fixtures and structures where penetration into fastener connection points is required. This product wicks into voids by capillary action and allows very simple preventive maintenance by permitting thread locking without dismantling equipment.

Other mechanical locking methods such as spring washers, wire retainers and locking bolts can be used to achieve similar retaining capabilities but these can add substantial cost to the fastener assembly while sometimes also adding significant time to assembly as in the case of locking wires. Threadlocking adhesives prevent threaded fastener failure and they are quick to apply and much less expensive compared to mechanical locking methods.


Gasketing Compounds

MRO activities also often include adding or replacing gaskets to seal flanges and pressurized connections. Many industries require heavy use of gaskets including pulp and paper industry, power generation, water treatment,oil refining, mining, marine industries…etc. Gasket replacers are a type of sealant that is applied in place on a component in a viscous consistency and is cured in place to produce a precisely matching seal as an alternative to rubber gaskets and O-rings. MRO gasketing compounds are easy to dispense thixotropic grades, removable even on soft metals like brass and aluminum. After curing, they form soft, flexible gaskets in any size or shape, provide excellent adhesion to metals, glass, ceramics, plastics, prevent corrosion and provide high temperature resistance. These cure-in-place gasket solutions fill small voids, prevent leaks and resist high pressure when fully cured. They will not crack and help ensure leak proof operation and easy disassembly.


Instant Bonding

Instant adhesives are another important MRO product. Mostly available as single component products, Instant adhesives provide immediate bonding on a wide variety of surfaces. They are used to repair broken parts, bond dissimilar parts easily and create a hard seal in seconds. They offer many benefits and are used in manufacturing industries, such as automotive, transportation,building, construction, furniture, electronics and MRO. For maintenance, repair and operations industry, they are commonly used to repair conveyor belts, nylon rails in production line and do temporary fixturing and lock set screws to calibrate instruments. Their widespread usage is based on their ease of use,excellent adhesion on a wide range of substrates and their outstanding chemical and temperature resistance. With a tolerance for robust end use environments and production areas, instant adhesives show excellent chemical, temperature and humidity resistance to motor oil, transmission fluid and gasoline.

Structural Bonding


Structural bonding adhesives are ideal for permanent repairs on structural assemblies. With excellent impact, temperature and environmental resistance to severe environmental conditions, many structural adhesives need minimal surface preparation, bond dissimilar materials, such as metal, ceramic,wood, concrete and plastic and can replace or reduce use of mechanical fastening methods, such as rivets, screws and welds. Compared to these mechanical fasteners, structural bonding adhesives have improved aesthetics by producing smooth, uninterrupted surfaces, lower labor costs and faster manufacturing speeds. These adhesives produce a stronger bond when the substrates are fragile or the surface application area is larger.
Structural adhesives provide the natural advantage of dispersing stress across the entire bonded surface while most traditional mechanical fasteners focus stress in points around the fastening locations and producing stress “choke points.”

Retaining Compounds

Retaining is a method for assembling press and slip parts and filling the inner space between components. Retaining compounds are ideal for bearings,retaining shafts, gears, pulleys, sprockets, sleeves, pins, bushes and couplings. They are high and moderate strength products, which typically tolerate high loads, fill voids, prevent corrosion and bond close-fitting cylindrical parts. Retaining compounds also help assure 100% contact to produce maximum adhesion between mating surfaces. When used properly, retaining compounds prevent the distortion of the mechanical components by increasing the strength of the final assembled product.

Thread Sealants

Leaking pipes and tubing can result in costly loss and equipment damage up to and including machine failure. Thread sealants prevent fluid loss,minimize downtime and lower the cost of maintenance. They fill the space and cure between male and female threaded pipe fittings creating a 100% seal and securing them from leakage. Whether the joint will undergo vibrational loosening, temperature cycling, corrosion or extreme pressures thread sealants will help to maintain and seal pressurized systems.
Sealants often replace tapes which can shred over time and pastes which may harden and chip, both producing system contaminants that may damage components and block filters. Some sealants offer important features such as non-hardening or non-shrinking materials or instant sealing to meet specific application requirements. Even when pressurized fluids are not present, thread sealants maybe indicated if there is regular disassembly required which can wear on threaded parts or if there is a risk of corrosion from chemical and environmental conditions. In most cases, application of sealants is simple requiring only a small amount to be brushed on and excess sealant can be wiped away without chemicals or solvents. Disassembly can be achieved easily with ordinary hand tools.

Surface Preparation

It is important to clean and prepare components and surfaces before the application of adhesives and sealants. Any loose material should be brushed away and liquids should be cleared. When further surface preparation is advised, primers are available to stabilize existing rust, cover the rough surface and, protect from further corrosion. Activators are also available to increase cure speeds and reduce fixture times of adhesives. These materials are essential when bonding substrates with low surface energy and can make the difference between successful MRO applications and failure waiting to strike.

Metal Cement / Weld Sealant & Copper Anti-Seize

Metal cement adhesives are designed for quick repairs of worn machinery parts. This type of adhesive fills significant cracks and gaps while sporting excellent chemical and temperature resistance. Weld sealants, by contrast, are applied on welds, castings and powder metal parts to fill voids on the micro-porosity level. Weld sealant is particularly advised when welding pressurized fluids which can “sweat” and leak through microscopic holes in welded seals.

Anti-seize lubricants are also heavily used in MRO activities and they do exactly as the name suggests:
  resist seizure and lubricate parts for smooth motion. This helps to protect metal parts against rust, corrosion, seizing and galling. They provide a shield against metal to metal contact, lower friction, fill irregularities and imperfections, resist welding, hardening or setting and allow for quick disassembly of threaded joints. The use of an anti-seize product is an excellent way of preventing corrosion, especially in hot, acidic and caustic environments.

Summary

Adhesives and sealants for industrial maintenance, repair and overhaul solutions seal and protect threaded joints from corrosion, retain bearings, bushes and cylindrical parts into housings or shafts, protect metal parts from galling, seizing and corrosion, instantly bond a wide variety of materials, repair tanks and pipes and clean rust and more! For emergency repair and preventative maintenance, itis very important to find the right product and it is strongly recommended to collaborate with an adhesive professional. Hernon Manufacturing, Inc.
®produces over 5000 adhesives and sealant types and uses a full in-house chemical laboratory to ensure quick turn around on testing and development projects. An on-site machine division allows Hernon® to build,service and integrate unique dispensing systems to even the most exacting specifications. This horizontal integration helps Hernon® to provide customers with a Total Solution for any unique application.

Hernon Manufacturing is headquartered in Sanford, FL. and maintains an ever-expanding network of over 100 distributor and partner locations around the globe. Already shipping to over 60 nations, Hernon
® can provide adhesive solutions to manufacturing operations anywhere in the world.


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