Why Is My Spray Paint Bubbling?

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Spray paint is a fantastic medium for getting a smooth appearance on your project, and many people use it for a whole variety of different projects – but it isn’t as simple as grabbing a can, shaking it, and spraying the surface that you want to cover. You need to do more than that if you want to ensure that the paint creates a smooth, even surface and does not bubble or warp.

If you’re wondering “why is my spray paint bubbling?” you are not alone; many people run into this problem and find themselves struggling to get the paint to stay smooth and adhere properly once they have painted a surface. This often results in having to strip the whole area down and redo it, which is highly annoying.

One of the biggest keys to getting a good coat of spray paint is proper preparation; you need to make sure that you are using the right kind of paint for the surface, and you need to prepare the surface correctly before adding the paint. This should ensure that the spray paint does not bubble, but instead creates a satisfyingly even layer on your project.

Why Is My Spray Paint Bubbling?

If your spray paint is bubbling, it is likely that you have done something wrong while applying it, either during the application or during the surface preparation – and unfortunately, there are quite a few things that it could be, so narrowing it down may take some time and effort. Blistering and bubbling in spray paint often occur when you put the paint on in a layer that is too thick, but they may also happen if you put a second coat on too quickly, or if you dry the paint in damp conditions.

Often, the blistering occurs because the layer of paint on the outside dries quickly, but there are still volatile substances on the layer beneath, and these can no longer escape easily. They will evaporate in pockets, causing bubbles and ripples in the paintwork, and ruining the surface. Be particularly aware of this if you are painting in damp conditions, because the dampness will increase the paint’s drying time significantly, and may mean that you have to wait a lot longer before applying a second coat.

Your spray paint may also bubble if it is applied to a surface that is dusty or too smooth, because both of these things will prevent the paint from sticking properly. You need to make sure surfaces have been sanded down and wiped with a damp cloth before you paint them. This should help to ensure an even application of the paint.

How To Keep Spray Paint From Bubbling!

The best way to keep spray paint from bubbling is to maximize the drying time; make sure you read the manufacturer’s recommended drying time before you start, and allow at least this amount of time between coats. If the room you are painting in is damp, increase the drying time significantly and make sure that each coat has completely dried before you consider adding a second one. Although spray paint does tend to dry fast and may feel dry, it needs time for the compounds to evaporate before you add more paint, or it will bubble.

You should ideally try to spray paint in dry conditions, and make sure that the painted item remains somewhere dry while the paint dries. Warmth will also help to speed up the drying time and ensure that you can apply a second coat of paint without too much risk of it bubbling.

We have already discussed preparing the surface carefully, and this is a critical part of keeping your spray paint from bubbling; a surface must be clean, dry, and free from grease before you try to paint it. Painting an unprepared surface, especially a greasy one, will result in bubbles and ripples anywhere that the paint cannot stick. You must therefore take the time to clean and prepare items, and have a suitably ventilated space for drying them in if you want to spray paint successfully.

Why Is My Paint Bubbling When Applying?

If your paint keeps bubbling when you apply it, you should check whether you are using the right kind of paint for that particular material; if the paint cannot stick to the surface properly because it is the wrong kind of paint, it is bound to bubble. Make sure that you have selected the right paint for your material (e.g. a plastic-suitable paint for plastic, wood-suitable for wood, etc.), and use an appropriate primer if this is recommended by the manufacturer. This should give you a much better chance of success and minimize the bubbling.

You should also check that the area you are painting in is dry and free from dust; if you paint in a wet environment, the paint’s volatile compounds will struggle to evaporate, and this could cause bubbling even if you don’t add a second coat of paint. A well-ventilated, dry, indoor space is the best spot for spray painting – so try to avoid painting outdoors unless you really have to (but remember that ventilation is crucial so you don’t breathe too many fumes while painting).

Sometimes, spray paint may bubble because you have applied it unevenly; if you find that the paint is bubbling in some areas but not others, you may have put it on too thickly in those spots. When painting, try to hold the can at a fixed distance from the object, and move it steadily so that it is constantly applying an even amount of paint.

Why Is My Second Coat Of Spray Paint Bubbling?

If the first coat of spray paint adhered well but the second coat is bubbling, you almost certainly did not leave enough time in between the two coats of paint, and you needed to wait for longer. The compounds in the first layer had not finished evaporating, and as the second layer dried, they caused pockets to form, leading to a bubbling effect.

If this has happened, you can try lightly sanding the second coat down to remove the bubbles and smooth the surface. Leave it to dry for 24 hours at least, and then wipe down and dry the surface to remove the dust, and apply a fresh coat of paint. This may be enough to make the project look great again, but you need to make sure you have fully dried the undercoat, or the next coat will just keep bubbling.

Sometimes, you will need to strip the paint back further, so make sure you reapply the primer if necessary. If you don’t, the first coat of paint may not take properly, and then any further layers will fail to adhere too. Being patient with each part of the application will give you much better chances of success.

Why Is My Spray Paint Bubbling On Plastic?

Plastic can be a challenging surface to paint on, and if you are struggling to get your spray paint to adhere properly to the surface, you should first check that it is actually suitable for use on plastic – because some spray paints are not. You should also make sure you have a suitable primer on the surface before you start painting it.

Additionally, you may need to sand the surface of the plastic before you start, because the smoothness of plastic can make it very difficult for the paint to grip it properly. Sanding it – even lightly – will provide a key for the paint or the primer to grip onto, and this will help to ensure that the first layer sticks well. That first layer will provide a basis for future layers to cling to and should minimize bubbling.

It is important to do good preparation when you want to spray paint on plastic, because it is such a difficult surface. Taking the time to get it right early on will mean you don’t have to spend hours sanding and repainting.


If you find yourself wondering “why is my spray paint bubbling?” on a regular basis, it’s likely because you are applying the paint too thickly, or not allowing enough drying time in between coats. If you don’t let the paint dry properly underneath before you add a new layer, the evaporation from the first layer will cause blistering. Good preparation, clean surfaces, and checking that you are using appropriate paints will also be critical to success.