Synthetic adhesives (such as anaerobic Loctite adhesives) find applications across various industries that includes Construction, Electronics, Marine, Sports, Automotive, Aerospace, and DIY hobbyist pursuits. Adhesives have been evolving over the years, now transforming into a wide range of products, ensuring there is a different, more specific type of adhesive for each joint, assembly system or surface. However, some basics have not changed, such as Pre-treatment procedures. Most professional users will agree that surface treatment should not be ignored. The reason is simple—you want the bond to be strong, last longer. This is best achieved when the surface is properly prepared before applying the adhesive. However, all pre-treatments are not created equally. Surface specific pre-treatments can improve joint durability and can enhance overall lifecycle of joints in an assembly.
This blog post will definitely give you all the information you need before you use an adhesive on an inactive or passive surface. It will help you understand the importance of an activator which is often neglected.
What are the benefits of using the right surface pre-treatment?
- Improves component’s service life
- Improves mechanical performance of joint
- Enhances joint durability
- Increases the ability to bond with multiple adhesives, including Polytetrafluoroethylene and Polyolefins
What is the purpose of pre-treatment?
A close molecular contact between adhesive and adherend is necessary in order to establish a strong bond. Right surface pre-treatment improves the degree of contact which can be optimized by chemical adjustments stimulated by pre-treatment rendered on the adherend surface. Read ahead to understand the many advantages of using pre-treatment:
- Pre-treatment also safeguards the adherend surface—critical in industrial or manufacturing environments where highly reactive chemical vapors are the norm. Pre-treatment is necessary for metal surfaces as it creates another layer on the surface that is otherwise likely to react with atmospheric impurities. These chemical reactions can impair the overall durability of the bond over a period.
- To preserve the adherend surface in its pristine form, it is important to bond the surface. This means investing a few hours in pre-treatment or covering it with a surface companionable primer. The primer creates the perfect surface for applying the adhesive.
- Pre-treatment helps to eliminate weak boundary layers like weak oxide scaling that is often found on metallic substrates or plasticizer residue on the surface of polymers that eventually eat into the lifecycle of the bonded surfaces.
- Pre-treatment also helps in producing a particular adhered surface topography by ensuring better quality of the surface, increasing the surface area which is easy to bond and has a greater probability of sustaining the bond.
What are the types of pre-treatment?
Multiple pre-treatment techniques are available that cater to diverse industry-specific and purpose-specific requirements. These techniques can be divided into 5 groups depending upon the nature of the treatment:
- Surface Roughening: This technique employs abrasive materials that eliminate unwanted layers on the surface. These layers, often inconspicuous, impair the strength of bonding. Professional adhesive users will agree that a roughened surface texture is better on any day rather than a surface that is lustrous or has residues or grime of any type.
- Physical Treatments: The technique involves cleaning the adherend surface and restoring the balance between chemical components by exposing it to controlled charges—Plasma, Flame and Corona discharge are the most common methods in this type of treatment.
- Cleaning/Degreasing: The organic solvent or alkaline aqueous solution helps in removing organic materials like oil, wax or grease from the adherend surfaces. This can be successfully done by dipping, spraying or wiping.
- Chemical Treatments: When adherend is immersed in an active chemical solution, it removes or dissolves away impurities on the surface, making the surface better positioned to bond apart from chemically activating it for better bonding.
- Primers: Primers are substitutes for elaborate surface treatments that can be time consuming. Primers are easier to apply as compared to chemical or physical methods. Even DIY users can use primers as they are easily available in easy-to-deploy forms like sprays that need little professional help to use. Better quality primers also contribute towards creating an additional layer of protection over the underling surface.
Loctite recommends the use of Loctite SF 7075 Activator before the application of Loctite 324 which is a structural bonder. Loctite 324 offers the strength of an epoxy and the speed of an instant, fixturing in 5 minutes when used in conjunction with this product.
We recommend the Loctite 7649 or Loctite 7471 Primer for use with Threadlockers. Primers or Activators are used with thread lockers when a certain thread locker is used to activate an inactive surface. Loctite 7649 is the most common primer used with thread lockers like Loctite 243, 263.
Active Surfaces :- Brass, Copper. Bronze, Iron, Soft Steel, Nickel
Inactive Surfaces:- Aluminium, Stainless Steel, Magnesium, Zinc, Black Oxide, Cadmium, Titanium, others.
This basically means that you must use an activator like Loctite 7649 when using a thread locker with a High tensile Blackodized bolt or a zinc coated bolt used in your assembly. These Activators will help speed cure times for faster returns, speed curing for larger gaps and deep threads and also act as a cleaning agent.
The third type of activator that is commonly used is one which is used with cyanoacrylates to activate low energy surface like plastic. Loctite 770 is used to make polyolefin and other low energy surfaces suitable for bonding with Loctite cyanoacrylate adhesives like Loctite 406, Loctite 407 etc.
Bohriali.com is among Asia’s biggest, most comprehensive online hub of industrial-strength adhesives. You get the assurance of finding globally popular adhesive brands under one roof. Curated with the best in online shopping tools, the online store guides you towards making a well-informed decision. You can choose from a wide range of synthetic adhesives and order bulk quantities too. Today, the online store is positioned as India’s leading provider of Loctite industrial adhesives—Loctite is the international leader in the niche of innovatively engineered sealants and adhesives. This is a testament to the fact that Bohriali chooses to associate with only the best brands in this industry!
If you have a query regarding any of the products displayed on this store or application of any product, please reach out to us via phone or email:
+91 95455 33033
Summary:
Pre-treatment is important for synthetic adhesive as it boosts the bonding and delivers best results. The selection of a pre-treatment should be based on factors such as cost, production, durability, adherend surface, health and safety. Bohriali.com is the one-stop online store for industrial sealants and adhesives, including pre-treatment products.
