Permabond ET5428 and ET5429 are high-strength two-part epoxy adhesives that were formulated to seamlessly bond composite materials.

Composite materials such as carbon fibre, fibre-reinforced plastics (FRP) and glass-reinforced plastics (GRP) are becoming increasingly popular in industry, mainly due to their low weight and high strength. They are frequently used in the automotive, aerospace, construction, and energy industries, among others. Permabond ET5428 and ET5429 provide exceptionally high strength on these materials

Due to their rubber toughening, ET5428 and ET5429 offer more than just very high bond strength, however. They also provide excellent environmental, impact and vibration resistance – key factors when we consider the type of applications composites tend to be used in, such as cars. They also offer good heat resistance for epoxy adhesives, continuously withstanding up to 120°C (250°F).

Permabond ET5428 and ET5429 also display exceptionally high peel strength, especially when compared with standard epoxy adhesives. Even when compared to MMA structural acrylics, which are known for their high peel strength, ET5428 and ET5429 perform better. Their high peel strength means that both products are more adept at coping with difficult joint designs.

Why composite adhesives need to be tough

Products made using composites often experience:

• Dynamic loads and vibration
• Elevated service temperatures
• Mixed substrates and gap variations

Standard adhesives – even epoxies –  can struggle under these conditions. Permabond ET5428 and ET5429 however, offer the toughness, strength and environmental resistance required for long-term performance on composite materials.

Key Benefits of Permabond ET5428 and ET5429

In addition to their toughness and durability, both ET5428 and ET5429 bring a lot to the table. They are lightly thixotropic, with excellent flow control. This makes them very smooth and easy to dispense by hand – meaning no need to go to the gym before you can get them out of the nozzle! This thixotropy also makes them well suited to vertical applications, as the adhesives don’t slump or sag after applying. They’re also highly suitable for any application requiring a gap fill.

In terms of substrates, these two epoxies bond a lot more than just composites. Materials bonded effectively by ET5428 & ET5429 include:

• Ceramics
• Metals such as aluminium, mild steel & stainless steel
• Plastics like polycarbonate & PEEK
• Nylon
• Timber
• Many others

Bonding dissimilar materials is also not an issue for these products, so you can gladly bond composites to metals or to plastics, for example. The rubber toughening built into both products gives them the strength and flexibility to handle differences in thermal contraction (CTE) between substrates. This ensures a strong, long-lasting bond that withstands changes in temperature from weather or processes like thermal cycling.

ET5428 vs ET5429 – when to choose which?

Permabond ET5428 and ET5429 are products offering broadly similar benefits – they both offer exceptional bond strength and durability on composites and many other substrates. However, there are some key differences between them to consider when choosing which one to use.

The biggest difference between the two adhesives lies in their curing speed. ET5428 cures quickly, reaching handling strength at room temperature in 30-45 minutes. On the other hand, ET5429 offers a very long open time, reaching handling strength at room temperature after between 6 and 10 hours. Depending on the needs of your project, you may require an adhesive that cures more quickly or more slowly. For example, if you’re bonding a larger surface area, you may need an adhesive with a longer pot life. Note that, being epoxies, a warmer environment will speed up the cure of both adhesives – at 60°C (140°F) a full cure is reached in 1 hour (ET5428) or 2 hours (ET5429).

In terms of colour, ET5428 is available in both cream and black. This makes it suitable for colour matching to key composite materials such as carbon fibre, FRP and GRP. ET5429 is charcoal, matching carbon fibre very well.

Possible Applications 

Both ET5428 and ET5429 can be used in a wide variety of industries and applications. Some examples below:

Automotive: Bonding lightweight composite panels. Adhesives replace the need for fasteners or any drilling, ensuring a lightweight, aesthetically pleasing finish. They ensure a 100% seal with no moisture ingress.

Aerospace: Interior panel bonding

Construction: Special effects on facades – replaces unsightly fasteners

Marine: Mast bonding, various objects on yachts

Summary: key product features

To summarise, the key features of Permabond ET5428 and ET5429 are:

• Lightly thixotropic – excellent flow control
• Excellent on composites, metals, plastics and many more
• Outstanding shear & peel resistance
• Rubber toughened epoxies – great environmental, vibration and impact resistance
• Easy to dispense by hand
• Great for gap filling
• Good heat resistance
• ET5428 – available in cream and black
• ET5428 – fast handling strength
• ET5429 – long open time, good for large bond areas

If you’d like to find out more about these products or to discuss your application with us, please get in touch.