Gluing Steel: A Simple Guide to Bonding Metal

Bonding metal and the different types of metal glue can be a bit confusing, and that’s why we’ve put together this simple guide.

A variety of adhesives can be used to connect metals. Given the numerous alternatives, selecting the best metal adhesive might be difficult. Each chemical has its own set of advantages. Here’s a quick rundown of them:

• Metal adhesives like structural acrylic adhesives and epoxies are perfect for producing strong bindings that withstand stress, temperature, and chemicals.
• Threadlockers, pipe thread sealants, retention compounds, and FIP gaskets are all examples of anaerobic adhesives. Metal adhesives and sealants are the only applications for anaerobic adhesives. 
• The strength of cyanoacrylate adhesives develops quickly. Take, for example, methyl cyanoacrylate. These bonds are resistant to non-polar solvents and work well under shear. If you need a metal adhesive with impact resistance or resistance to polar solvents, look into structural adhesives.
• UV Curable adhesives are perfect for undetectable glass-to-metal connections. Metal hinges, knobs, and fittings are frequently bonded to glass doors with these.
• MS Polymer adhesives are good for gluing thin metal sheets, such as vehicle panels. Because of the low shrinkage, there is no read-through (you can’t see where the adhesive is applied through the panel), resulting in a pleasing appearance.

Generally speaking and depending on the application metal glues fall into three types:

epoxy, polyurethane, and super glues.

Let’s talk about them a bit more.

Source: Loctite.com

Epoxy Glue

Epoxy glue provides the strongest bonds for steel and other metals. These two-part adhesives combine a resin and a hardener, forming an incredibly durable chemical bond once cured.

Epoxies can resist high temperatures, vibration, and chemicals — making them ideal for structural metal bonding. Products such as Loctite EA 9466 or Araldite 2021 are excellent examples for gluing steel securely.

Polyurethane Adhesives

Polyurethane glue bonds metal to a variety of surfaces, including wood and plastic. It cures with moisture, forming a waterproof bond. While not as strong as epoxy on steel, polyurethane adhesives offer good flexibility and shock resistance — useful when bonding dissimilar materials.

Cyanoacrylate (Super Glue)

Super glues — or instant adhesives — bond metal surfaces quickly and cleanly. They’re perfect for smaller repairs or precise joins. Products like Loctite 415 provide rapid strength and work well for gluing steel in applications that don’t experience heavy stress or heat.

Anaerobic Adhesives

MS Polymer Adhesives

MS Polymer glues are flexible and good for bonding thin metal sheets, such as automotive panels. Their low shrinkage prevents visible read-through on finished surfaces — ideal where appearance matters.

Step-by-Step: How to Glue Steel

1. Preparation

Work in a clean, well-ventilated space. Cover your workspace and wear nitrile gloves. Test-fit components before applying any adhesive.

2. Clean the Surfaces

Use a clean cloth to remove oil, dirt, or grease. For the best results when gluing steel, lightly roughen the surface with fine-grit sandpaper to help the adhesive grip.

3. Apply the Adhesive

Follow the manufacturer’s directions.

• For epoxy, mix equal parts of resin and hardener.
• For super glue, apply a small amount to one surface only.
• For polyurethane, apply thinly and clamp tightly.
  

Avoid over-applying — a thin layer bonds better.

4. Join and Secure

Press the parts together firmly, ensuring full contact. Clamp if needed to maintain alignment.
Epoxies often need up to 24 hours to fully cure, while cyanoacrylates set within minutes. For the strongest possible bond, leave the assembly to cure overnight.

Best Practices and Tips

• Use epoxy for structural and load-bearing metal joints.
•  Choose polyurethane or MS Polymer for flexible, weather-resistant joints.
•  Pick super glue for quick, small repairs.
•  Clean surfaces thoroughly — even small contaminants weaken the bond.
•  Always check the adhesive’s temperature and chemical resistance for industrial applications.

ConRo Electronics, as a supplier of all major types of thread locking compounds, will provide you with an impartial approach to assessing your application and operation.

We’ll show you how to improve product reliability while increasing performance and lowering costs. Our team of technical support specialists will provide your company with dependable global supply, unrivaled efficiency, and superior technical support.

Feel free to contact us on 0208 953 1211 or send us an email to info@conro.com