When it comes to bonding two substrates, choosing the right adhesive for the job is crucial. Especially if you have a structural bonding application, you need an adhesive that is strong and will last.
3M is a trusted and popular brand for various types of adhesives. From craft projects to industrial applications, 3M probably has a product for it. In particular, 3M acrylic adhesives and 3M epoxy adhesives are popular choices for industrial and structural bonding applications. They are known for their great strength and can be used to replace welding, bolts, screws, or other mechanical fasteners. While both can create strong, permanent bonds, the best one for a particular project will depend on the specific application.
At Gluegun.com, we are reviewing the differences between 3M acrylic adhesives and 3M epoxy adhesives including their pros, cons, and applications to help you determine which type of adhesive is best for your needs. We will even provide a few product recommendations.
What Are 3M Acrylic Adhesives?
Sometimes called methyl methacrylate or MMAs, acrylics are fast-curing and high-strength adhesives that often come in two parts and are composed of acrylic or methylacrylic polymers. They are used in various structural bonding applications with different substrate materials and cure at room temperature. They can also come in a wide range of colors, cure speeds, and unique properties to meet different bonding needs.
While exact properties vary from product to product, some of the pros of 3M acrylic adhesives include:
- Diverse bonding capabilities- These products are designed to bond a variety of different types of materials including dissimilar or difficult to bond substrates.
- Minimal surface preparation required- One pro of 3M acrylic adhesives is that they generally require minimal surface preparation before application.
- Fast cure times- Compared to epoxies, these products tend to have a faster cure time for faster production times.
- Good flexibility- While strong, this type of adhesive also has good flexibility compared to epoxy.
On the flip side, some potential cons of 3M acrylic adhesives (compared to epoxies) include their:
- Lower chemical & heat resistance
- Lower strength
- Strong odor
- Shorter shelf life
What Are 3M Epoxy Adhesives?
3M epoxy adhesives are a group of very high-strength adhesives that typically consist of a resin and hardener that are mixed together at application. They are made up of chains of carbon linked to other elements such as hydrogen, oxygen, or nitrogen and are typically used in structural bonding applications. Like acrylics, epoxies can be formulated to have different properties to meet more application needs.
Every product is slightly different, but some key pros of 3M epoxy adhesives include:
- Very high strength- Epoxies are generally considered the strongest adhesives for a variety of substrates like metal, plastic, and glass. They are often the go-to choice for heavy-duty, high-stress applications.
- Excellent chemical resistance- These products have a high resistance to a variety of chemicals such as solvents, grease, oils, salts, acids, and some bases.
- High heat resistance- These products are capable of withstanding very high temperatures.
- Wide variety of properties- With different work lives, cure speeds, viscosities, flexibility, and toughness, they can fit a wide range of application needs.
- Long shelf life- When stored properly at room temperature, many 3M epoxies have a shelf of up to two years.
Compared to acrylics, some potential downfalls of 3M epoxy adhesives are their:
- Surface preparation requirements
- Lower flexibility
- Longer cure times for the same work life
- Inability to bond some difficult substrates
Key Differences Between 3M Acrylics and 3M Epoxies
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Property
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3M Acrylic Adhesives
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3M Epoxy Adhesives
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Bond Strength
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Strong bonds
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Very strong bonds
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Cure Time
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Full cure in 24 hours (for many)
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Full cure can take days
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Surface Preparation
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Minimal/no surface preparation required
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More surface preparation often necessary
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Flexibility
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More flexible
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Generally stiffer and more rigid
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Chemical Resistance
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Good resistance to some chemicals
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Excellent resistance to many acids, solvents, oils, and more
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Shelf Life
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Generally 6-12 months
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15-24 months
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Heat Resistance
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Generally 200-250°F
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300-350°F
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When to Use 3M Acrylic Adhesives
You should likely choose a 3M acrylic adhesive if the bond requires:
- Bonding dissimilar substrates
- Bonding difficult substrates
- Immediate bonding strength
- Flexibility
- Exposure to dynamic stress
With these types of applications in mind, 3M acrylic adhesives are often used in automotive assembly, aerospace manufacturing, and construction.
When to Use 3M Epoxy Adhesives
While different products have slightly different bonding capabilities, you should likely choose a 3M epoxy adhesive if the bond requires:
- Maximum strength
- High chemical or heat resistance
- Long-lasting durability in harsh environments
- A special property not found with the acrylics
Because of their great strength and resistance to environmental factors, 3M epoxy adhesive applications often include use in heavy-duty industrial manufacturing, marine applications, automotive bonding, and electronics.
Product Recommendations
While these types of adhesives follow some generalities, there are some exceptions. 3M is always working to improve their product lines and make them better. If you are looking to find a 3M acrylic adhesive or a 3M epoxy adhesive that can make up for what may normally be one of their shortcomings, we may be able to help point you in the right direction.
A common complaint about acrylic adhesives in general is their smell. While it isn't necessarily dangerous with the right safety precautions, it can be unpleasant to work with. To combat the stink, there are a series of low odor 3M acrylic adhesives now available. These products are designed to have the same capabilities of other acrylics but without the horrible smell.
3M Toughened Acrylic Adhesives
If you are looking for an acrylic that has the strength of an epoxy, these products have been toughened for higher tensile, shear, and peel strength. They have great impact and shock resistance so they can hold successfully in more demanding environments.
One common complaint about epoxies is their lack of flexibility. These products are formulated with higher flexibility, so they are better suited for applications exposed to vibration, impact, and thermal expansion.
Need More Help?
Ultimately, choosing between a 3M acrylic adhesive and a 3M epoxy adhesive will depend on the application requirements. You should take into consideration the bond strength required, environmental factors, materials being bonded, and your budget. If you are not sure what product to choose, do not worry. Our adhesive experts can provide you with a personalized product recommendation.
