Gorilla Glue is a true miracle adhesive. It’s so strong that its manufacturers claim that it can bond almost any two surfaces! While this radical statement holds up in many cases, what if your mission is to stick two pieces of plastic together? Can Gorilla Glue save the day?
How Does Gorilla Glue Work?
First off, it’s worth knowing a bit about how Gorilla Glue works. Gorilla Glue is a moisture-activated polyurethane adhesive. Basically, this means that it sets in the presence of moisture. On a more technical level, it creates bonds between the ions in the water and those in the glue itself, setting super-hard.
This relies on the presence of microscopic amounts of water in or on the surface that Gorilla Glue is being applied to, which is one of the reasons it’s such a great metal glue. Metal has a micro-pitted surface, meaning it’s got lots of little holes and divots on a microscopic level which trap moisture.
This is perfect for Gorilla Glue, because the water activates the setting reaction, and also enables the other part of Gorilla Glue’s secret magic; as it hardens it expands, filling these little crevices and gaps and locking tight.
Consequently, on surfaces that have little micro imperfection like glass, ceramics, and metal, Gorilla Glue creates a super-tight bond.
Oddly, Gorilla Glue doesn’t work so well on surfaces like wood. Wood and leather are too porous, and if you’re going to use a polyurethane glue on them it has to be one that contains an accelerator to speed up the hardening process.
What About Plastics?
You will have noticed a material that’s strikingly missing from that list of appropriate uses for Gorilla Glue. Unfortunately, bonding plastics is not Gorilla Glue’s strong point.
The nature of many plastic surfaces means that there just aren’t enough places for the glue to expand into, and the way that plastic repels water prevents Gorilla Glue from forming strong bonds.
Because most plastics are non-porous, there’s nowhere for the CO2 produced by the reaction that sets the glue to escape to, which creates pockets that weaken the adhesive bond.
Don’t abandon all hope just yet, though. Gorilla Glue’s original formulation does work on some plastics better than others. The manufacturers state that the original Gorilla Glue works on most plastics, though people report varying degrees of success.
Part of the problem is that plastics are all formulated differently, so even two products made of the same basic chemical plastic will have slightly different compositions.
This throws up some interesting quirks as far as the applications of original Gorilla Glue is concerned. For example, it is indicated for use on PVC sheeting, but not on PVC pipes.
It also simply doesn’t bond well on polypropylene (PP) or polyethylene (PE) plastics, or any form of plastic containing a high plasticizer or rubbery plastics, or plastics with a high oil content.
This rules out a fair few types of plastic, which might leave you wondering whether there is a use for Gorilla Glue here at all.
More Than One Gorilla Glue
You may be wondering why we keep saying original Gorilla Glue while discussing its suitability for plastics. The reason is that there’s not just one Gorilla Glue!
There are actually a variety of formulations of Gorilla Glue that all start with the same basic concept, but act slightly differently to produce better results on different surfaces.
Take Gorilla Super Glue, designed to provide a stronger bond than the original with a shorter drying time. It works best on small areas, much like any other super glue you might use. Can Gorilla Super Glue provide the answer to your plastic problem?
Unfortunately, Gorilla Super Glue suffers from the same deficits as its classic stablemate. It works okay on some plastics but fails to securely bond many others. It’s also not suitable for use on PP or PE plastics, or the oily and rubbery plastics that original Gorilla Glue doesn’t work on.
There’s another possible answer out there in the form of Gorilla Epoxy, which is marketed as working on most plastics. However, the original Gorilla Glue is also supposed to work on most plastics!
The same limitations apply with the epoxy formulation as they do with the glue, in that PP and PE plastics are excluded straight away, along with low surface energy plastics, ones with high oil content, and PVC pipes, though Gorilla Epoxy supposedly works very well on PVC sheets.
Sadly, it looks like Gorilla Glue just isn’t going to cut it for a lot of plastic bonding applications.
If you need to bond PVC sheeting to something then it’s a great solution, but for a huge range of everyday plastics, including ones used in the home and in construction, you’re going to need to look for an alternative.
It turns out that sticking plastics together with glues just isn’t that easy. A lot of the time you need to do a fair amount of preparatory work to any plastic surface that you want to create a lasting adhesive bond with, including a range of methods like sanding and priming.
You can buy special compounds for priming and then adhesives that work with them, but in a lot of cases it’s just too much work to avoid replacing the item you’re trying to fix. With most things that are made out of plastic, your best solution is to find a replacement for the item itself.
Can Gorilla Glue Be Used On Plastic?
In summary, the answer to whether or not Gorilla Glue can be used on plastic is a highly qualified yes. It will bond to some plastics, but not reliably. It will absolutely not bond to other plastics at all! However, it’s not the only glue that falls short in this area.
You can use hot glues or some resin compounds, but you might just find yourself coming to the conclusion that, frankly, the best thing to do is to replace the item entirely.