Do I Need Epoxy or Polyester?
Fabrication professionals have many choices when it comes to selecting equipment, tooling, and supplies. When it comes to supplying a fab shop with adhesives, how do you know what projects require epoxy and which can take polyesters? Is one better than the other? What are the differences between the two? In this article, we will take a look at these two adhesives and explain the answers to those questions.
Why So Many Glue Types?
If you have ever wondered why there are so many kinds of adhesive out there, you are not by yourself. If you ask hundred different people that question, you might get as many different answers.
Asking why there are so many different kinds of glue available is like asking why there are so many different kinds of cars. Here are three reasons why there are various kinds of glue:
- People have different preferences.
- Some adhesives excel in areas where others do not.
- A characteristic that appears to be a weakness in one application might actually be what you want in a different application.
Since each of those reasons can change based on who is using the glue, what they are gluing, and what their preferences are for the given job, it is good to know a little bit about different kinds of adhesive. Knowing some basics will allow you to select which glue you prefer for each project you begin.
Comparing Epoxies and Polyesters
Two prominent kinds of glue that you will find when looking for stone adhesives are epoxy and polyester. Each of these glues have different properties. These properties may or may not be what you are looking for; depending on the material, the project, or your preferences. Let's take a look at the properties of each and review when you might want to use each type.
Properties of Polyester
Polyester resins are described as being easy to use and for many applications polyester will work just fine. Because polyesters are easy to use adhesives, production can run more smoothly at times. Additionally, these adhesives are a lower cost than other products; as a general rule. They tend to be a bit more stable in the presence of UV rays.
As we mentioned before though, no glue is the best at everything. So, the polyesters do have some drawbacks when compared with other types of adhesives. For one thing, they have a tendency to "delaminate" when subjected to rapid temperature change. Additionally, they can draw up in joints. Finally, as a general rule, polyesters are not as strong as epoxies.
So when should you reach for a polyester adhesive? Well, considering the properties just discussed, polyesters are usually a good choice for indoor use where the temperature is not likely to change rapidly and for applications where high bond strength is not critical.
Properties of Epoxy
Although you will find that in the United States, polyester resins are often referred to as epoxies, true epoxies differ in chemical make up and the term specifically applies to a very specific glue.
Epoxy can be substantially harder to use for some and it is generally a bit more costly. However, for some projects it may be the kind of glue you need to use. As a general rule, epoxy is significantly stronger than its counterpart. Epoxies also can be "dialed in", so-to-speak, because adjustments can be made to the hardener to cause it to cure at different rates. Additionally, epoxy tends to bond better with smooth, hard surfaces than does polyester. Finally, epoxies do not succumb when exposed to rapid temperature change; so they can be used outdoor.
You will want to consider using an epoxy when your project requires a very strong bond. Structural bonds are an example of when an epoxy would be your go to glue. And because of its temperature stable nature, epoxy would most likely be a better choice if the project may be exposed to temperature fluctuations. Outdoor jobs benefit from epoxy adhesives.
As we have seen, various situations call for different types of glue. Which one you choose will most likely depend on what your project entails and whether it will be exposed to the elements. Whatever your project needs, you will find a cartridge glue right here that will handle the job.