What is the Best Glue for Plastic?

Do you require dependable glue for your next plastic model construction project? Or perhaps you need to repair a broken piece? Several types of glue are available for joining plastics, but determining which glue is best for your needs can be difficult.

Some glues behave differently on various plastics, while others differ in drying time or durability. With the right glue, you can repair any plastic, and we’re here to help you find the best solution for your project.

The Best Glues for Plastic

The best glues for plastic for most household projects are epoxy, super glue, or solvent cement, but the best ones vary depending on the product and the amount of time you have. Super glue is convenient for small fixes, but liquid epoxy glue has a stronger hold.

Epoxy putty can be shaped with your hands and used to fill in gaps. Keep in mind that many types of glue do not provide a long-lasting hold on polyvinyl chloride (PVC), so if you want to join PVC, use an industrial-grade solvent cement specifically formulated for the material. Most glues are incompatible with polypropylene or polyethylene plastics, so always check the glue’s packaging to ensure that the formula is compatible with your plastic.

Super glue, also known as a cyanoacrylate, is an excellent choice for everyday repairs because it dries quickly. Super glues intended for use with polypropylene or polyethylene may contain a primer to prepare the plastic. When using epoxy, you must combine a hardener and a resin. Epoxies take longer to harden than cyanoacrylates, giving you more time to work with them.

Finally, gluing PVC surfaces together at home is best achieved with a two-step solvent cement chemically welding PVC surfaces together. While the application procedure can sometimes be messy, PVC cement can solidify in minutes. Some adhesives are resistant to water, and some are safe to use with potable water (check the packaging).

Take a glance at the tensile strength, measured in pounds per square inch, to assess the strength of any glue (PSI). A higher PSI indicates a stronger glue. However, depending on the materials you’re adhering together, tensile strength can differ slightly in practice.

 

While some adhesives dry to the touch in a few seconds, many types of glue demand several hours (usually up to 24 hours) to completely harden or fully cure. Because adhesives can dry in a variety of colors varying from clear to black, always select a cured color that is appropriate for your project.

Plastic Gluing Tips

Select the Proper Glue

First and foremost, choose the appropriate glue for the plastic you’re working with. Consider whether the glue will be subjected to harsh temperatures or elements, as this may reduce its effectiveness. Finding the best glue for the task will ensure a strong bond.

Clean Surfaces

Before you begin gluing, ensure that all the surfaces you wish to join are clean. Dirt and grime should be avoided, as they can decrease the efficiency of the glue’s performance.

Don’t Overdo It

When using strong glues, less is more. Excessive application may result in dried glue buildup and longer drying times. Only use enough glue to complete the task.

Clean Up Carefully

Ensure you properly store your glue after wiping away any stray glue streaks. Remove any excess glue stuck in the nozzle, which can dry and lock the bottle shut. You should also keep the glue in a dry, cool place away from extreme temperatures.

Top Plastic Glues

Gorilla Glue

Choose Gorilla Super Glue Gel when you need one that dries quickly and clears. It hardens in 10 to 45 seconds, so you won’t be caught holding the plastic bits together for a long time. However, the manufacturer recommends giving it 24 hours to cure before completely adding any weight to the plastic.

Its tensile strength varies from 500 to 1,500 PSI, depending on the materials you’re gluing together. Furthermore, the formula is thick enough that it is simple to control where it goes.

 

While the glue is not waterproof, you can use it on various surfaces, including vertical surfaces such as walls. The cap has an anti-clog metal pin that helps keep the glue fresh after it’s been opened. You can purchase in packs of two or ten or one 20-gram bottle at a time.

Loctite Super Glue Plastics Bonding System

Due to its two-step process, this super glue system appears to be an epoxy at first glance, but it is a super glue that has a primer to assist in prepping smooth plastics. You don’t need to combine the two formulas; apply the plastic primer, let it out to dry, and then apply the glue. The glue hardens within seconds, but it takes 12 to 24 hours to cure completely.

All plastics, including polyethylene and polypropylene, are compatible with the Plastics Bonding System. It’s water-resistant (but still not waterproof), dries clear, and its tensile strength ranges from 290 to 2,900 PSI.

Also, it doesn’t shrink as it dries and, once hardened, can be drilled and sanded. However, using it on surfaces that come into contact with food or potable water is unsafe.

J-B Weld Plastic Weld

When you need to fill in chips, gaps, or cracks, this Plastic Weld glue contains both the hardener and the resin in one stick. This glue has a low tensile strength of 600 PSI, but unlike other options, you can shape it with your hands before drying.

To use the putty stick, snip off the amount needed, knead the putty to combine the two ingredients, and then cast it in place. Plastic Weld takes roughly 25 minutes to set and three hours to cure completely.

It hardens to off-white color and can be painted, sanded, and cut. The manufacturer recommends it for use on trim, auto bumpers, and vinyl surfaces, among many other things.

Once set, Plastic Weld is safe for potable water contact and water-resistant. However, while some users report successfully sealing leaks with this product, J-B Weld’s Water Weld epoxy putty is a wiser choice if you’re gluing parts that you will submerge for an extended time.

a package of J-B Weld, showing 'hardener' (red tube) and 'steel' (black tube of resin)

Plastic is used in various applications, from toys to model building. Its unique flexibility and durability make it extremely useful. Still, it also causes issues when rebuilding with glue, as many adhesives can fail to bond properly with or dissolve the plastic. You must choose the appropriate glue for the job, perfect for your specific plastic type.