In this article we will shed some light on the following topic: “Is spray paint flammable after it dries?”, we will discuss other essential questions about spray paints and understand what they are made of.
Is spray paint flammable after it dries?
The short answer is: It’s not flammable after it dries. The most flammable components in these sprays are organic solvents, but they dissipate some time after the application. The dried paint can still catch fire but only under a lot of heat, which isn’t usual.
What are spray paints?
Spray paints are liquid, gas or liquefied paints contained in an aerosol can. You can also call them aerosol paints.
The cans have a button on top, so you can apply the product directly to a surface. This is an alternative to traditional brushwork.
There are advantages to using aerosol paint. Since the product that comes out of the can is very thin, it can creep under small cracks and spaces, so it’s much easier to apply.
Spray paints are also more toxic than regular paints since the particles can be easily inhaled, so protection equipment is always required.
There are many kinds of spray paints and surfaces. You may need to apply spray primer to the surface before applying the spray, so the paint can actually stick to the surface. You may also need a finisher.
Here is a list of the most common spray paints:
- General Purpose
- Oil Based
- Rust Preventive
Each of these has specific flammability but we assume all they are flammable while in the can (unless, perhaps, the water-based spray paints). But to be considered a fire hazard after dried is complicated.
Spray paint fumes are flammable for how long?
After applying spray paint, the area will have a higher flammability risk as long as it’s wet. Is better to wait for the total drying time, according to the fabricant.
Once all the solvents evaporated, the risk of flammability drops abruptly. It’s important to say that when a sprayed paint feels dry to the touch it does not necessarily mean that it’s fully dried.
The drying time
As you could see before, there are many kinds of paints. It’s not easy to generally dictate how all of them are going to work but we can safely assume a few things.
Even if you read the drying time on the label, there are still some factors that can make it longer. We point out:
- The room size
- Paint types
- Amount of ventilation
- Surface porosity
- Type of material
All these factors combined will dictate how fast your paint is going to dry. There are ways to speed up this process, but the safer way is to wait and let it dry naturally.
Other methods like burning the paint can be very dangerous and/or ruin your work. Even if you are an experienced professional, keep in mind that incidents occur when we are less expecting them.
The manufacturers usually set a period of 24h so the paint can dry. But for some paints, it is 15 minutes.
But once again, if the room is not ventilated well or if the walls or materials are rough for example, it could be longer. We advise you to wait up to 48h.
Metal surfaces, for example, have a faster drying time. They can be ready in a few hours.
Tips to reduce the fire hazards
Always read the label. We usually neglect labels thinking that they are too simple or that we already know it all.
But think with yourself: how many mistakes could you have avoided in your life if you had known more, paid more attention, or thought it through before acting?
Our labor requires awareness of our tools and ourselves, especially when dealing with highly flammable products like spray paints.
If you are painting indoors, solvents will surely take more time to evaporate.
When it’s too cold, paint can take longer to
So, here’s a resume of the instructions to avoid fires:
- Read the safety instructions and warnings that are in every spray can;
- Keep fire and heat sources away from the paint, the spraying paint, and the surface at all times;
- Never spray over lightning and electrical fixtures. But if you have to, make sure no electric current is coming through. Sparks can ignite flammable gases and create an explosion;
- Never puncture the can;
- Keep the ventilation high. Paint vapors are toxic and highly flammable. The wind can push the particles apart, reducing these risks;
- Store flammable paints in a dry place.
In-depth into the flammability problem
What does it mean when something catches fire? What is the difference between a flammable and a combustible compound? Can dried paint eventually catch fire?
Combustible or flammable are just names we give for something that can catch fire under normal circumstances, and something that requires more than the usual to start a fire.
Usually, we name something as flammable when there’s a high risk that it will catch fire at a temperature below 38ºC (100ºF).
This is also related to the ability of a compound to ignite on its own, with just a little easiness. This happens because flammable compounds are usually volatile, or can become volatile easily.
Gases and vapors are more willing to catch fire because their molecules are sparse and can react more easily with the oxygen in the air.
Take diesel, for example. If we take a flask of it and light a match and throw it on, nothing will happen. This is because diesel needs to be heated a little before ignition (even so, never try this at home).
But if we leave it exposed to the sun it would evaporate easily, creating a thin mist of organic volatile compounds on top of the liquid.
As a result, an ignition source could easily light it up, creating a fire or explosion. This is one of the reasons why fuels are stored underground in gas stations.
So, the flashpoint of a material is the lowest temperature at which it starts liberating volatile compounds. Things with lower flashpoints are the most flammable.
Gases like the solvents and propellants used in spray pants are already volatile because they are gases, which is why they are so flammable.
Virtually, anything is combustible but not all things are flammable.
But every flammable thing is combustible.
Dried paint flammability
But what about dried paint?
Well, it depends. There are many different paints, but there’s one thing that we can assume for the majority of them: dried paints have a high flashpoint.
Once the paint is cured, it shouldn’t ignite easily. As we saw before, once the volatile organic compounds evaporated, the risk of flammability drops a lot.
But the paint itself is often composed of organic compounds as well. Make no mistake: paints can ignite once they are on your wall, DIY project, metal surface, or any other surface but the conditions required to do so are extreme.
It would also mean that you didn’t follow the instructions on the label.
If the material where you are applying paint will eventually receive heating of any kind, you should acquire heat-resistant (high-heat) paint. Otherwise, you could burn the whole place.
Dried paint can’t catch fire easily, but attention is required so the paint cure has been accomplished. But there are many kinds of spray paint, some are more flammable than others.
Frequently Asked Questions (FAQS): Is spray paint flammable after it dries?
Why is spray paint explosive?
It’s explosive because the can is under pressure, so the combustion reaction if there is an ignition source, is very strong
Is spray paint toxic?
Yes. Spray paints normally have highly toxic compounds that could cause cancer and even problems in unborn children. But this is only possible if the safety instructions on the label were not followed.
Is spray paint waterproof?
They can be waterproof, but you need to look for a specific product that states so. Water-based spray paints are normally not waterproof.
Bruice, Paula Yurkanis. Organic chemistry. Pearson, 2017.