Resin is a universal water-resistant gum found in most homes in the United States. But does its water-resistant nature also make it heat-resistant? To answer that, we need to analyze a bigger question: is resin flammable?
So, Is Resin Flammable or Not?
There are different resins whose flammability depends on their purity and water content. But a good number of resins can catch fire and few are flammable when uncured. When cured, certain resins, like epoxy resin, are not flammable and, under normal conditions, can even resist fire.
To clarify things, let’s run through the different resins there are:
Is Common Resin flammable?
Common resin is the natural resin obtained from plants. This resin is insoluble in water and thus used for various things like paints, adhesives, and varnishes.
Using flammability language, the regular resin has a flash point of 350⁰F and an auto-ignition point of 570⁰F. Technically, these values are below the 100 F threshold for flammable liquids. So, we can’t technically say that common resin is flammable.
However, when heated hot enough, the regular resin can catch fire when wet and uncured. This makes one reason you should never place your resin canister near a naked fire.
Is Epoxy Resin flammable?
Unlike regular resin, epoxy resin is synthetic. Specifically, most brands make their epoxy resins from polymers of an epoxide. To dry or cure it, these brands either use UV light or other subtle methods.
For that reason, it is better than regular resin because it has two parts; it is a better adhesive, and it dries much quicker. But besides that, epoxy resins are like regular resins.
For one, they both have the same flash point of 350⁰F and an auto-ignition point of 570⁰F. So, technically, they are both non-flammable. But with the right heat, epoxy resins, like regular resins, can catch fire.
One more thing, epoxy resins are those resins that we often use for coating tabletops, floors, laminates, composites, and in artworks. Now, you know you need to keep safe around it when wet.
Is Polyester Resin flammable?
Polyester resins are also synthetic resins. But unlike epoxy resins, they contain organic acids and alcohols. In this article, we already explained just how flammable alcohol can be, and you can check it out.
Now, because of its alcohol content, polyester resins have a flash point of 90⁰F. That means polyester resins are flammable because their flash point falls below the 100⁰F threshold.
According to the safety data sheet, the flash point of some polyester resins containing a substance called methyl methacrylate can even be lower.
So, polyester resin is as flammable as it comes. Compared to other resins, you need to be extra, super careful while using polyester resins. If you need to learn more about how to handle it, this web document can help.
Is Casting Resin flammable?
There are no specific resins called casting resins. In most cases though, acrylics, urethanes, epoxies, and polyesters fall under this category.
However, most artists find polyester resins easily castable. This is because they believe that you only need to add a small amount of a catalyst called MEK peroxide to get things up and running.
Now, as said earlier, polyester resins are highly flammable, and so are many casting resins.
Is Fiberglass Resin flammable?
While epoxy resins can resist fire to a certain degree, it has one demerit – it is expensive. So, users opt-in for cheaper ones like poly-resins or fiberglass resins, which are much more flammable.
Like casting resins, fiberglass resins is another kind of polyester resins. Although this time, fiberglass resins contain a hard mix of polyester resins and fiberglass strings. You can learn more about their pros and cons from this article.
Fiberglass resins have flashpoints between 89⁰F and 180⁰F depending on the product. So, technically, we can still say that fiberglass resins are flammable, and you should handle them with extreme care.
Why Some Resins Are Not Flammable When Cured
Curing resin is transforming the resin from liquid to solid. To do that, you need to heat it, drive water away and add some hardening materials to it.
After curing, most resins, like epoxy resins, become even more compact. So, their bonds will take a large amount of heat before breaking or catching fire, if at all. So, they relatively become more heat-resistant.
However, there is a common misconception out there that UV resins are flammable. Well… UV resins are epoxy resins cured with ultraviolet light. Since cured epoxy resins are not flammable, UV resins are not flammable as well.
Does Resin Melt in Fire? At What Temperature, Does It Melt?
While discussing the kinds of resins out there, you’d notice that the two major kinds of resins today are epoxy resins and polyester resins. So, we’ll focus on those two here.
When heated, epoxy resins melt anywhere between 150⁰F and 600⁰F. This depends on the moisture content of the resin. If it’s wet, you can expect it to melt slower and at a high temperature.
As for polyester resins, their melting point is between 149⁰F – 500⁰F, and this depends on the polyester used. Although long before this, the polyester resin would already burn with an intense flame.
Is Resin Toxic to Burn?
When heated, resins produce toxic fumes. These fumes can cause the following health complications:
- Nasal, throat, and eye irritation
- Lung problems and asphyxiation
Which Kind of Resin Can Explode on Heating?
While the most common types of resins used are liquid, some resins also come in powdered form. Good examples are the polyester and epoxy resin powders used in electrostatic coatings.
According to a research paper from the Swedish Fire Research Board, polyester and epoxy resin powder can explode like other dust particles like flour. However, these resins require lower ignition energies.
What this means is that resin powders are much more explosive than ordinary powders. Although in liquid form, polyester resins will explode much faster than epoxy resins because of their lower flash point.
In this article, we noted that not all kinds of resins are technically flammable, but all of them can catch fire at the right temperature.
For instance, polyester resins, which have a flash point of 89⁰F, are flammable. Whereas, epoxy resins, whose flashpoints are about 350⁰F, will only catch fire when heated above that.
But whether flammable or otherwise, all resins pose one or two health risks when heated or when exposed to air. To avoid any complications, always do the following while working with resins:
- Always wear gas or nose masks. These guards you against the toxic fumes from the resin you’re working with.
- Avoid placing resins near a naked flame, electrical spark, or any other ignition source.
- Resins can auto-ignite when heated to 570⁰F. To prevent that, occasional spray water to cool your resin canisters to keep them safe.
That said, we’ll wrap this article up. If you wish to learn more about other flammables, you can visit this page for weekly exclusives.