If you expect wood glue to stick on plastic, you will be disappointed. Even if you can get them to stick together initially, the hold won’t last. So, what about super glue — does it work on plastic?
Super glue does not work on plastic very well, because its main ingredient, cyanoacrylate, expands into the glued materials. Since plastic is impermeable, it repels moisture, and thus, the glue cannot expand into the material. For a strong bond, choose other adhesives.
We rely on plastics so much, yet few adhesive glue types will work on it. Let’s explore why it’s difficult to find the right adhesive for plastics. You’ll also learn helpful techniques for making plastic adhere, so keep reading.
While super glue can be used on plastic, it won’t create a strong, long-lasting bond. That’s because super glue is impermeable, so when moisture is present, the glue will expand into the material that’s being glued.
Evaporation is key to how carpenter glue and similar glues adhere surfaces together. While the water evaporates, the remaining particles link together. Since the glue shrinks, the items need to be clamped together to ensure the surfaces stick together.
Super glues also rely on evaporation, but there are some differences. One is that they expand instead of shrinking, which is why directions for superglue always stress that less is more.
The other key difference between glues that depend on particles sticking together, super glues, which are part of the cyanoacrylate family of glues, create bonds using water.
Cyanoacrylates are sticky, fast-acting, and highly adhesive glues. When a cyanoacrylate glue makes contact with water, it creates a bond between two surfaces by expanding into the two surfaces.
Super glue needs moisture and surfaces they can expand into to work. The humidity in the air provides enough moisture for most surfaces, including plastics. So why won’t they work well on plastics?
The answer is that plastics repel moisture. In addition, since the glue cannot expand into the plastic, the bond created between plastic and another surface is weak.
To make a super glue stick to plastic, you need to create a surface on the plastic that allows the glue to have something to grab on to. Besides super glue, you will need sandpaper, isopropyl alcohol or soapy water, and a damp cloth.
Below are the steps for applying super glue on plastic:
- Use alcohol or soapy water to remove grease from the plastics.
- Let the plastics dry.
- Use 120–200 grit sandpaper to create a rough surface, which will give the glue something to bond to.
- Brush the super glue onto both surfaces.
- Push the pieces together firmly. The goal is to eliminate excess air bubbles, so the surfaces should be pressed together with even pressure.
- Even though the surfaces will bond quickly and feel strong, clamp the pieces together with rubber bands, tape, or vise for at least 24 hours.
After 24 hours, undo the clamping. At this point, the surfaces should be bonded tightly, but the curing process can take several additional days.
Even though all super glues are cyanoacrylates, most super glues have similar bonding qualities, and the most significant difference between them is the additives. These additives do not necessarily mean additional strength but are rather meant for cosmetic purposes.
One category of super glue products forming a stronger bond uses a combination of glue and filling powder, such as the Pratley Powda Bond Adhesive, available on Amazon. The kit includes super glue and a filling powder.
Mix the powder with the glue to create a strong bond, which you can then use to repair holes and gaps.
The Gluesmith Plastic Repair Kit is another super glue kit that includes fillers. It can resist up to 280℉ of heat and can be used on larger scale projects such as car plastic, headlight repairs, and restoration on boats, canoes, and ATVs.
As you surf the internet, you’ll find sources that claim that Gorilla Super Glue is superior to Loctite, but another says that Loctite is a better glue. Yet another site says that both are inferior to a third product.
What they fail to mention is that the superglue you choose must match its application.
For example, Gorilla creates a very soft and flexible bond, so it will be better when you need flexibility. However, it does not have so much strength, so glue such as Loctite would be a better choice if you need a strong bond.
This YouTube video from Project Farm does an excellent job of showing how the major super glues work for different applications.
Superglue can work on metal to plastic, but it might be difficult for them to stick to each other. Both materials are difficult to bond because they are non-porous. You need to make both surfaces rough first, preferably using steel wool, before gluing.
Of course, you can use whatever that works, but steel wool often works better on metal. Keep in mind that you only need to create a rough surface, not sand it down.
Super glues can make a strong enough bond for items that won’t have a lot of pressure during use. These glues will be acceptable for projects such as gluing models but not applications in which the bond will be stressed.
Epoxy glue is a better choice in those situations.
You’ll have more success gluing wood to plastic than plastic and metal. The wood is porous, allowing super glue to expand into it. You will again need to scuff up the plastic surface to give the glue something to hold take hold of.
Although superglue will bond plastic to wood, it is not an ideal choice. Two-part epoxies, such as Gorilla Glue’s 2 Part Epoxy, will create a stronger bond.
Super glue is an excellent glue because it creates strong bonds quickly. However, the same properties that let it form those bonds make it difficult to glue plastics to other materials.
Related: Does Gorilla Glue Work on Plastic?