Waterproof Expert

Waterproofing tips & tricks

What is the best waterproof glue for plastic?

Selecting the right adhesive for bonding plastic surfaces is crucial especially when waterproofing is a requirement.

To achieve a reliable and long-lasting bond that can withstand water and moisture, it is essential to select an adhesive that is compatible with the specific type of plastic you are working with. This compatibility ensures that the adhesive will effectively adhere to the plastic surface.

In this quick guide, we’ll explore some of the best adhesive options when it comes to bonding plastic.

Figure out what plastic it is first

The effectiveness of the glue can vary depending on the specific type of plastic you’re working with.

Every kind of plastic responds differently to glues. Some plastics like polypropylene, are impossible to glue. You can use the strongest adhesive on the market, it doesn’t work.

For example, Sugru Mouldable Glue is an excellent adhesive but won’t bond to oily plastics like polypropylene, polyethylene, or Teflon.

On the other hand, plastics like PVC are easy to glue using PVC glue.

Some glues are solvent-based. They work by chemically melting plastic together.

To ensure the best results, take the time to read the product labels and carefully follow the instructions provided by the manufacturer.

Additionally, conduct a small test on a surface before applying the adhesive. In this manner, you can test if the adhesive is compatible with the plastic and achieves the desired outcome.

What is the strongest waterproof glue for plastic?


Epoxy glues have exceptional bonding strength and waterproof properties. They consist of two components—a resin and a hardener—that you need to mix before application.

Epoxy resins create a strong, long-lasting bond on various plastics.

Epoxy is pretty much the best all-purpose adhesive. It should be your weapon of choice for plastics.

For more information on the best Epoxy solutions, check out Project Farm’s guide:

Polyurethane Adhesive

Polyurethane adhesives offer excellent water resistance and flexibility on plastic surfaces once fully cured. They are available in different formulations. Some are flexible and rubbery. Others are hard and tough.

Cyanoacrylate (aka Super Glue)

Cyanoacrylate, aka super glue, is a fast-acting adhesive that bonds quickly and firmly. While it may not be as flexible as other adhesives, it can provide a strong and waterproof bond on many plastic surfaces.

However, Super Glue is not waterproof forever.

I recommend checking out Project Farm’s video on the best Super Glue brands:

Silicone Adhesive

Silicone-based adhesives and sealants are well-suited for waterproofing applications. They form a flexible and durable bond on plastic and are resistant to water and extreme temperatures.

You can use silicone-based adhesives for bonding ABS plastics, rubbers, and more.

Why is it so challenging to glue plastic to other plastic?

Plastic’s strength comes from the fact that the long polymer chains stretch back and forth across the surface. When plastic breaks, those chains are broken.

The role of glues and adhesives is to intermingle some of those broken ends together at the breakpoint. In other words, your adhesive tries to cling to some of those broken ends. But the catch is they can only cover a limited distance.

That’s what makes gluing plastic to other plastic so challenging.

For more information about the best adhesive to use for bonding plastic or other materials, you can check out Makezine’s adhesive chart.

It will come in handy if you don’t know what type of adhesive to choose.


The best adhesive for gluing plastic is a solvent-based glue that dissolves the plastic pieces into each other. Dissolving both sides allows them to fuse together for a better hold.

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