Permabond Engineering Adhesives: Application Tips

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THREADLOCKERS • Permanent • Removable• • Low, Medium, High Strength• • High Temperature Resistant• • Chemical Resistant• • High, Medium and Low Viscosities• • Weld Porosity Sealants• • NSF/AnSI 61 Certified• STRUCTURAL ACRYLICS • One and Two part• • No Mixing Required• • Bead on Bead and Activator Cure Grades• • Room Temperature Cure• • Non-flammable• • Very High Strength• FLEXIBLE GASKETMAKERS • Replace Conventional Gaskets• • High Temperature Resistant• • Easy to Apply and Remove• • Chemical Resistant• RETAINING COMPOIUNDS • High Temperature Resistant• • Chemical Resistant• • High Strength Formulas• • Metal Repair• • Range of Viscosities• • NSF/ANSI 61 Certified• TOUGHENED INSTANT ADHESIVES • Quick Set• • Wide Range of Viscosities• • Products for Most Substrates• • High Temperature Resistant• • Low Odor• • Non-Blooming• THREAD SEALANTS • Potable Water & Gas Grades• • Low and Medium Strength• • High Temperature• • Resistant Grades• • Various Viscosities• • NSF/ANSI 61 Certified• • UL Listed Grades• EPOXIES • Two Part• • Static mix• • Room Temperature Cure• • Excellent Chemical and Water Resistance• • Clear & Flexible Grades Available• UV LIGHT CURABLES • Optically clear• • Non-yellowing• • Single Part• • Impact and Peel resistant• • Solvent-free•

• Shelf Life and Storage
• Temperature Effects
• Suitable Surfaces
• Surface Preparation

Permabond has over 60 years of adhesives experience. During this time, we've amassed considerable knowledge and expertise regarding the application, handling and storage of adhesives. With this knowledge, Permabond has become a uniquely capable resource for communicating the positive affects Permabond products have in many areas around the globe. Recognizing the significance of this responsibility, we have produced this section to serve as an introduction to the most common considerations regarding the proper utilization of our products:

Shelf Life & Storage

Proper Adhesive Storage Means Greater Profits

Over the lifetime of an application, you may significantly reduce your adhesive usage by paying close attention to the adhesive shelf life and storage conditions recommended by Permabond. Because of the various chemistries involved in the adhesives that Permabond manufacturers, we have developed specific storage condition recommendations by product. These recommendations should be reviewed prior to selecting an adhesive for your application and should be followed whenever possible. The shelf life of each Permabond adhesive is based on our experience with that product under controlled conditions. Therefore, we are certain that these adhesives when stored per our guidelines will maintain their performance over the course of the shelf life given. Unfortunately, if the adhesive has not been stored according to the recommendations given we often have no information as to how it will perform.

Adhesive Shelf Life

The shelf life of a product is the time it may be stored under specified conditions with no significant changes in properties. It is recommended that each adhesive family be stored under its specific conditions. Many adhesives are sensitive to extreme temperatures and some to light and humidity exposure.

Generally, Permabond recommends that each adhesive type be stored within the temperatures indicated below. Please refer to the Technical Data Sheet for the specific product information you require.

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Temperature Effects

Controlling Cure Rates and Production Speed

Many environmental conditions affect how adhesives cure and perform over long periods of time. One of the most significant environmental factors is temperature. Minor changes in temperature can have major changes in cure speed and storage life of adhesives. Most organic adhesives have maximum continuous operating temperatures and if exposed to higher temperatures for long periods of time their performance drops significantly. Permabond has put together some guidelines for your reference to eliminate or control the potential impact of temperature and other environmental conditions on your application.

Effect of Environmental Temperature

The temperature at which the adhesive is being applied and used will affect its cure. All cure times quoted in Permabond Technical Data Sheets are taken at 23°C.

The anaerobic sealants are affected by a rise or fall in the temperature of the area in which they are being used. The general rule is for every 8°C (15°F) that the temperature increases; the time required for the adhesive to cure will be halved. Conversely, if the temperature is 8°C (15°F) cooler the cure time will double.

Cyanoacrylates cure using surface moisture and are less affected by temperature. However, the humidity and the type of surface being bonded can affect cyanoacrylates.

Service Temperatures

Permabond's adhesives are organic in their chemistry and, as such, generally have service temperature ranges between -80°C to 250°C (-60°F to 482ºF). Please refer to the Technical Data Sheet for the specific product grade features including the temperature range.

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Common Surfaces and their Suitability for Adhesive Bonding

A critical factor in the success of any adhesive bond is the condition of the assembly surfaces being joined. Every assembly surface has unique characteristics, either inherent in its material make up, such as aluminum oxidation; or added to it during manufacturing, such as rust inhibitors. This guide provides an overview of several common materials and their suitability for adhesive bonding. Consult a Permabond representative for a complete assessment of your assembly surfaces and determination of the best Permabond adhesive for your specific application.

Aluminum and its Alloys

Surface appears clean but has a thin oxide film that weakens the bond between the true aluminum surface and the adhesive. Some oxide films may be stable enough to provide a strong bond without any surface preparation. Aluminum is the exception. Permabond can help you evaluate your aluminum and advise which method of pre-treatment would be most appropriate to optimize bond performance. Oxide films form immediately, even after surface treatment. Surface bonding must take place as soon as possible to achieve maximum adhesion strength.

Conventional Steel Alloys

Mild steel alloys typically present surfaces readily able to be bonded.

Zinc-plated Steel

Presents an oxide film that may weaken the bond between the true steel and the adhesive. Zinc plating may separate from the steel surface as a result of the adhesive. May require chemical treatment to eliminate the zinc separation from the steel sheet.

Treated Zinc-plated Steel

The treated surface is both unsuitable and unreliable for adhesive bonding. Certain chemical treatment methods can present workable bonding surfaces. Consult with a Permabond representative to evaluate treated zinc-plated steel surface bonding applications.

PVC-coated Steel

Structural joints cannot be formed on PVC clad surfaces of mild steel. Cyanoacrylate adhesives will provide good adhesion to the PVC surface.

Painted Steel Panels

Structural joints cannot be formed on the painted surfaces of steel panels. Several Permabond adhesives will provide good adhesion to painted steel panels. Maximum adhesion will be achieved by those Permabond adhesives that will flex with the bending of thin sheet panels.

Stainless Steel Alloys

Depending on the application, chemical surface treatment may be necessary. Surface preparation with abrasion and a solvent wipe is suitable in most cases.

Thermoset GRPs

Permabond cyanoacrylate adhesives bond well to these surfaces. Surface activated toughed acrylics may not provide suitable gap filling ability for large structural applications.

Acrylic-faced Thermoset GRPs

Structural joints cannot be formed on the acrylic face of these surfaces. Permabond cyanoacrylate adhesives will provide the maximum adhesion to the acrylic faced surface. The cyanoacrylate adhesive, in its liquid form, will cause stress cracking on the acrylic face after prolonged exposure. Use QFS10 or QFS16 to accelerate cure and minimize exposure to uncured adhesive.

Wood-faced Thermoset GRPs

Wood-faced Thermoset GRPs typically present surfaces readily able to be bonded. Several Permabond adhesives will provide good adhesion to these surfaces. Consult with a Permabond representative to evaluate wood-faced thermoset GRP surface bonding adhesives.

CRFPs

These structural composites, typically epoxy-based, bond well with a variety of Permabond adhesives.

ABS

Permabond cyanoacrylate adhesive will provide good adhesion to these surfaces. The adhesive, in its liquid form, will cause stress cracking on the surface after prolonged exposure.

Nylon

Extensive surface treatment may be necessary to achieve suitable bonding. Consult with a Permabond representative to evaluate nylon-faced surface bonding applications.

Polyolefin

Extensive surface treatment may be necessary to achieve suitable bonding. Consult with a Permabond representative to evaluate polyolefin-faced surface bonding applications.

Polyurethane

Presents a difficult surface for effective adhesive bonding. Consult with a Permabond representative to evaluate polyurethane-faced surface bonding applications.

PVCs

Permabond cyanoacrylate adhesives will provide a suitable bond to both rigid and flexible PVC surfaces.

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Common Surface Preparation Guidelines

Although many of Permabond's industrial adhesives provide excellent bonding to "as received" surfaces, proper surface preparation will dramatically improve adhesion strength and bond performance. A properly prepared component will present a surface that is uniformly clean, mechanically sound, and correctly textured. A prepared surface will ensure strong and durable bonds; particularly when harsh usage environments are present. This guide provides an overview of several surface preparation methods. Consult a Permabond representative for a complete assessment of your assembly surfaces and determination of the best surface preparation method for your specific application.

Surface Preparation - Solvents

If possible, remove surface oil or grease with an aqueous-based cleanser. If aqueous-based cleansers are ineffective, isopropyl alcohol is recommended. If isopropyl alcohol is ineffective, solvents such as acetone or methyl ethyl ketone can be used. It is recommended that the surface material first be tested as certain thermoplastics may crack or dissolve when reacting to various solvents.

Surface Preparation - Mechanical

Mechanical abrasion is a process of slightly roughening the surface of the component to be bonded. The surface roughness should be kept to less than 0.1 microns (0.004 millimeters) to reduce the possibility of small contaminants or air bubbles becoming trapped in the roughened surface and degrading the bond performance. Scarification is typically done with either an abrasion or a blasting process.

Surface Preparation - Abrasion

Abrade using 45 to 106 micron grit or a three-dimensional, non-woven abrasive fabric. Abrading can be done as either a wet or a dry process. If doing wet abrading, use only media designated as water-resistant. When preparing aluminum surfaces always use the wet method to prevent the oxide pores from clogging with abraded contaminants. Proper surface condition has been achieved when the surface can be immersed in clean water, and when removed a water film remains unbroken for 30 seconds. Do not use iron- or steel-based grits on aluminum, copper, or stainless steel components.

Surface Preparation - Dry Blasting

Typically used on metallic components. May also be used on heavy-duty plastics. Blast using 45 to 106 micron grit until the surface is uniform in cleanliness and texture.

Surface Preparation - Wet Blasting

Typically used on small metallic components. Blast using 1000 mesh grit suspended in either water or steam. In the event a system uses water-soluble additives, consult the system manufacturer to eliminate contamination of the surface by the additives.

Surface Preparation: Non-mechanical

Non-mechanical surface preparation methods are typically for only high volume plastic or composite component production applications. Non-mechanical surface preparation modifies the chemical characteristics of the component's surface to an optimum condition for adhesive bonding. Gas Flame Oxidizing: Economical and effective method of preparing plastic or composite surfaces. Rapidly adapts to changes in component topography.

Surface Preparation - Plasma Discharge

Also known as Corona Discharge. Economical and effective method of preparing plastic or composite surfaces. Best suited for components with simple, or flat topography.

Surface Preparation - Plasma Chamber

Utilizes a discharge chamber to process large volume component batches. Best suited for batches with complex, or multiple component shapes. Requires greater initial capital investment; provides greater volume and part type processing than other non-mechanical surface preparation processes.

Surface Preparation - Laser

Can be used for metal and plastic component surfaces. Requires extensive system design, and calibration. Consult with a Permabond representative to evaluate laser surface preparation for your application.

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