Why Does Spray Paint Crackle? (Plus How To Fix It & Prevent It)

Spray paint can be a quick and easy way to paint stuff and get your project over with quickly, but some issues can turn spray painting into a giant headache. One of the biggest irritations occurs when your spray paint crackles and cracks during and after the drying process.

Spray paint can crackle if it is applied when the temperature is too hot (paint dries too quickly), it is applied when the temperature is too cold (paint doesn’t adhere properly), or too much paint is applied at once (the paint dries unevenly and at different rates). To fix crackling spray paint, you will have to sand and repaint.

Read on to learn more about why spray paint crackles, how to prevent it from happening on your next project, and how to fix it if it already happened to you!

Why does spray paint crackle?

There are many reasons why your spray paint is crackling but most cases boil down to just a handful of reasons.

Here are the most common reasons why spray paint crackles:

• Temperature is too hot
• Temperature is too cold
• Too much moisture
• Too much paint
• Failure to dry paint between coats

Temperature is too hot

If you ever look at the back of a spray paint can, you’ll notice that there is always a ‘recommended temperature range’ when it comes to actually spraying the paint. That’s because paint works best under certain conditions.

In fact, according to spray paint manufacturer Krylon, the best temperature to use spray paint is between 50°F and 90°F. Any higher or lower than this and you’ll run into problems.

If you use spray paint above about 90°F, the paint will dry too quickly because the solvents mixed inside the paint will evaporate before the paint has had time to settle and dry. When the paint dries too quickly, it is likely to crack on the surface.

How to prevent it

To avoid this issue, try bringing your project inside or at least sit it in the shade outside for a while to bring the temperature down. Use a temperature gun or other thermometer to check the surface temperature of the material you are about to paint before you get started.

Temperature is too cold

On the other end of the spectrum, spray paint also struggles when the temperature outside is too cold.

If you use spray paint at temperatures below about 50°F, you can have problems with paint failing to mix inside the can properly or even spray out correctly, leading to problems with the paint itself. What’s more, when the surface you are painting is too cold, the paint will have a hard time adhering, especially something like metal.

How to prevent it

To avoid this issue, try bringing your project inside to warm up or place heaters around the project outside. Be sure to mix your spray paint can for longer than usual and keep the paint stored inside a warm place before you need it.

Too much moisture

If I told you that pouring water in your paint would probably cause problems, you likely wouldn’t be too surprised.

It shouldn’t shock you, then, to hear that too much humidity or moisture in the air can actually cause problems with spray paint.

Spray painting in areas of high humidity or spray painting objects that are slightly moist will prevent the paint from drying or adhering to the surface properly. As the paint dries unevenly, it will cause crackling on the surface.

How to prevent it

To avoid this issue, you can bring your project inside, use dehumidifiers, or even use hot air guns to dry any surfaces that need to be painted.

Too much paint

The final likely cause of your spray paint crackling is that you used too much paint, especially on flat horizontal surfaces.

While it is easy to see when you used too much paint on vertical surfaces (the paint will drip or run down), horizontal paint application issues are harder to notice because the paint will still lie flat.

However, when you use too much spray paint, then the paint will dry unevenly – the top of the paint will dry quickly because it is exposed to air, while the bottom of the paint will dry slower. This uneven drying can cause the paint to move, ripping it and crackling it as it dries.

How to prevent it

To avoid this issue, always use more light coats of paint rather than fewer heavy coats of paint. Also, be sure to let the paint dry fully in between coats of paint.

Failure to dry paint between coats

Finally, our last reason involves patience.

Although spray paint promises a quicker and easier way to paint, you still have to exercise patience throughout the process.

Failure to let spray paint dry properly in between coats of paint can cause crackling because the paint is drying at different rates, ripping and tearing as it dries.

How to prevent it

To avoid this issue, always wait long enough in between coats, about 5-20 minutes. The speed at which your paint dries will depend on the temperature, humidity, and type of paint used.

When applying more than one coat at a time, make sure to give each of them enough time to dry before adding another layer.

How to fix Spray Paint Crackle?

In most situations, spray-paint crackling is simple to fix, if annoying.

Yes, it’s more inconvenient and preferable to avoid, but don’t get panic if you see some crackling.

To repair your spray paint crackle, you’ll have to do a bit of sanding and then touch up the area with a fresh coat or two of paint.

Start by buffing out the crackled parts with a piece of medium or fine sandpaper. Then, clean and prime the surface and then buff again. After that, you can start painting.

If crackling still occurs, lightly sand the surface and then apply a thin layer of primer before reapplying spray paint. It is important to wait for the paint to dry before attempting to fix it. Make sure to move the sandpaper in small, circular motions to remove the flaking and achieve a smooth surface.

Here is a quick video that explains the process:

Spray Paint cracking on different surfaces and how to fix

One of the biggest perks of spray paint is that it can be easily sprayed on a wide range of materials. You can spray paint metals, plastics, wood, mirrors, glass, and ceramics.

However, each surface type has its own set of best practices to achieve the best finish. Unfortunately, spray paint can crackle on any of these surfaces.

Spray paint cracking on metal

Yes, spray paint can crackle on metal.

Because metal is such an excellent conductor of heat, it is easy for metal to get a lot hotter or a lot colder than the air around it. To understand this, just imagine a car sitting out in the hot summer sun – if you touch the metal body it is going to burn!

As a result, the most common cause for crackling on metal surfaces is related to temperature.

To avoid crackling spray paint on metal surfaces, be sure to normalize the surface temperature by moving it into a temperature controlled environment or finding some other way to heat it up or cool it down until it is in the ideal temperature range for spray paint, between between 50°F and 90°F.

Spray Paint Cracking on Wood

The most common reason why spray painting on wood will lead to cracking is that the surface is not smooth. The second most common reason is that you are trying to paint wood that has too much moisture in it, leading to other issues.

To avoid crackling spray paint on wood, be sure to prep the surface in advance by sanding it down and applying a high-quality primer. Doing so will provide a better surface for your spray paint to adhere to as well as create a moisture barrier between the wood and the paint.

Spray Paint Cracking on plastic

Plastic is super easy to paint and, ironically, that is one of the main reasons why you have crackling on your plastic.

You see, plastic is so easy to paint that people tend to rush through the job and fail to wait long enough in between coats of paint. When the first coat of paint isn’t dry, applying a second coat on top will cause the paint to dry unevenly, leading to crackling.

Always be sure to wait long enough before you spray that second (or third) coat!

Spray Paint Cracking on glass

Similar to plastic, glass can be deceptively easy to spray paint.

Glass has an incredibly smooth surface which is great for getting paint to lie down flat and get a smooth finish but it causes problems with the paint’s ability to adhere to the surface. As a result, you’ll need to let the paint dry for longer than usual and completely set before adding a second coat. Also be sure that the glass isn’t too cold or hot which will cause issues with drying time.

Why does spray paint crackle on the second coating?

If you do not allow your paint to dry, it is extremely simple to get cracking on the second, third, or fourth coating. This is because the previous coat is still moist, and the layer above it dries faster than the previous layer.

Related: How long does spray paint take to dry?

However, if you wait for your paint to dry between coats it is less likely you will experience this problem.

Thus after finishing your first coating of spray paint, wait for the paint to completely dry, then apply a second coating.

How to get the spray paint crackle effect on purpose?

While most people are trying to AVOID spray paint crackling, it can look awesome if you are trying to get the crackled look on purpose!

If you want to get that crackle effect with spray paint, here is a simple way to do it:

1. Apply two or three layers of spray paint.
2. While the layers of the spray paint are still wet, use a toothpick to apply some thick and chunky white craft glue on top. This way the surface will be uneven.
3. When the glue is dry, spray some more layers of paint on top with a distance of 6-8 inches between the can and the surface.
4. Wait for the layers of paint to dry and spray some more after 5-10 minutes.
5. After finishing the last layer of spray paint, wait an hour or two until the project is completely dry before moving it.
6. The spray paint crackle effect should appear after a few days when the layers dry and shrink.

Here is a cool video that explains the process on the body of a guitar!

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