Painting on cardboard is the real thing; many do it to actually paint and some paint it just to repurpose old cardboard, something can a signboard. But, cardboard is made from kraft paper, what type of paint can you use safely. It’s not like other drawing papers or canvas where you can unleash your creativity without thinking twice. But, with cardboard, you do have to take care a few things and you can’t just use any paint on the boards. After doing some research, I have compiled this article with a comprehensive guide on the type of paint used on the cardboard and how you can paint without damaging the board.
Types of Paint You can Use on Cardboard
- Acrylic Paint
- Oil Paint
- Spray Paint
Acrylic paint and spray paint are the two suitable options for painting on cardboard. The kraft paper on the cardboard being too delicate can’t stand most types of paint and may get damaged or warp. That said, acrylic and spray paint too can’t be applied directly on the corrugated cardboard. The board has to be prepared with primers and other layers before it could be painted or colored.
How to Prepare Cardboard for Acrylic Painting or Oil Painting?
If you try to paint directly on the cardboard without preparing it, you will notice that the paint soaks right in and leave a pale color on the surface, which should have been a bright color on other substrates. Many contemporary artists do use cardboard to paint on and are even sold in the market at a hefty price. Both acrylic and oil paint can be applied, replacing canvas, wood or paper; but, the board has been prepared to hold the paint. To prepare the cardboard it is applied with primer and gesso.
Applying Gesso on Cardboard
Before you paint on cardboard, you have to prevent the board from absorbing the paint. Without a primer, you have to apply multiple layers of color to get an opaque and bright print. To prevent it, the cardboard is first primed using gesso. Most artists typically use white acrylic gesso.
Gesso is a type of primer made of chalk, binder, and pigment which is typically white in color. If you want a colored gesso, you could mix the white one with your choice of acrylic color. You can buy gesso from the store or you could make one at home, on which we will discuss later.
To apply the gesso, use a foam brush or a sponge and lay two layers of gesso, end-to-end, one in vertical and another in horizontal. Let the gesso layers dry; leave it in a cool and dry place for 24 hours. Now your cardboard is ready to be painted on. However, if you find the layer to be too rough or course, you can sand it down using 500-grit sandpaper after it’s dry.
Instead of using gesso you could also prime the surface using white acrylic paint; but, for that, you have to use up a lot of white acrylic paint before creating an opaque layer to paint on. Gesso works best because it takes only a couple of coats. It creates a layer between the soaking kraft cardboard and the acrylic paint or the oil paint. You can also use gesso to prime wood, plastic or canvas. If the plastic surface is too smooth, you can sand it down before applying the primer.
Furthermore, if you have colored cardboard and want to retain its color after primer, you can use a clear gesso or another transparent acrylic medium. It can be applied to wood, canvas, and plastic as well.
How to Paint Acrylic or Oil Paint on Cardboard?
A major roadblock to painting on cardboard is that it curls or warps with moisture, which is why water-based paints don’t work on cardboard paper. Even after the primer layer, you have to make sure you don’t use too much water in your painting. Therefore, instead of dipping your brush or sponge into the paper, you should be using a dry brush. Bend and twist the bristles if it feels too stiff.
Instead of squeezing paint straight on the cardboard, which many artists do on canvas, you should squeeze out the paint on to the brush or sponge. You could squeeze a few drops of paint onto the palette and dip your brush in to before applying your paint. This will prevent any accidental excess paint on the cardboard and prevent paint patches which might sink in.
Avoid exposing your cardboard to any moisture; so, it is advised to use thin layers of paint on the board. Then let it dry completely before applying the second layer. To get your final picture, you will have to work with multiple layers of colors, as well as let it dry after each layer.
The process goes the same for both acrylic and oil paints. Cardboard is not a suitable substrate to paint on, however, with a little care, it can be achieved. You would be amazed to know that many artists work on cardboard and sell their painting at a hefty price.
How to Spray Paint on Cardboard?
- Pick a well-ventilated area such as your open garage. Make sure there’s plenty of room for the spray paint fumes to fly away, as they can be toxic. If you are spray painting cardboard, it is better to choose a warm, dry place with little to no moisture.
- Spray paint is tough to remove, so protect your floor and surrounding by laying a sheet of old paper or tarp under the cardboard. Prep the area with plastic covers if you are spray painting on a large piece of cardboard paper.
- Prep the paint can by shaking it for at least 2 minutes before painting. It is done to mix the pigment with the paint in the can, which can get separated over time. Then give a few second shakes every hour for easy flow of the paint through the nozzle.
- Hold the can at least 12 inches away from the cardboard you are painting on. Lightly spray paint the cardboard by running it parallel to the cardboard in a smooth motion. If you spray up close on the cardboard, the pain will sink in and warp or curl the cardboard. Make sure you don’t spray a section of the board more than twice, as it will saturate the board with too much paint and make it warp.
- To apply a second coat of paint, make sure the first coat is completely dry. You should leave the board to dry the first coat for 2 hours. If you are repurposing your cardboard as a sign or really trying to paint, you have to take special measures so that the paint doesn’t saturate, and cardboard doesn’t get destroyed in the process.
How to Prevent Warping and Curling of Cardboard?
- Many believe that only water or moisture is responsible for warping or curling the cardboard. Little do they know that PVA or a water-based filler during drying could also sink in and warp the board. Many would seal their cardboard to prevent water from penetrating into the board, but the PVA will simply shrink and the cardboard to warp and curl.
- Next, prevent your cardboard from moisture. Humid air alone can warp the cardboard. So, if you are using old cardboard, it might already be warped or curled to some extent.
- Prevent using wet paint on the board; which is why most enamels, acrylic or oil paints work with cardboards but watercolors make a nasty mess.
- Even after taking care of the above steps the board may still warp if it’s thin. So, it is always advised to work your paint on a thick double-wall or triple-wall corrugated cardboard.
How to Fix a Warped Cardboard?
Lay the warped cardboard on a flat table with the curled and warped face upward. Now place a sheet of flat plywood over the cardboard and weigh it down using books, metal tools firewoods, etc. Leave the plywood with the weight for a few days. After 3 days, remove the weights to check if the cardboard has flattened. To be honest, it may take up to weeks for the cardboard to fully recover from warping.
Using moisture and weights
You can moisten the cardboard only a little so that when it dries out under pressure, the cardboard will retain its flat surface. You dip the top plywood in water once or rub the table top with some water, but never dip the board in the water. Leave the weights on the pressed moist cardboard for a day. Check it every day to see if the cardboard has flattened.
How to Prepare Your Own Gesso?
Like I’ve discussed earlier that instead of purchasing gesso from a store, you can make your own. It is particularly helpful if you are a full-time artist and have decided to work on cardboard for a few weeks. The gesso is what you need to prime the cardboard before painting. It is also used to prep canvas, wood and plastic, to a layer that doesn’t let the water soak in.
Gesso is typically made from calcium carbonate, latex, and other chemicals. You would need a lot of gesso if you are a frequent painter and premium gesso primer can be expensive.
Here is one of the many recipes for creating your own gesso:
After mixing the first three ingredients, you will see that the solution is turning more into a solid blob than a liquid primer. So, add a few tablespoons of water to get a consistency close to the one purchased from the store.
The mixture will give you a gesso pretty close to the purchased ones. But the store purchased primer would be smoother and whiter. However, you can still use your own gesso if you apply a couple of layers, and if it is coarse or rough you can sand it out for a smooth surface.
Benefits of Using Cardboard for Painting
Cardboards have long been a popular choice of medium to paint on by age-old painters. Even today, many artists use corrugated cardboard to paint their inspiration. Here are some advantages of using cardboard over other substrates to paint.
- It is cheap and readily available. Painting on corrugated cardboard is fun and inexpensive. There’s no danger of wastage. It available for free and found in abundance.
- Cardboard is easy to cut and crop. You can work in various sizes of cardboard.
- Using cardboard for painting is more like repurposing which would otherwise be recycled.
- It is lightweight, so you can carry it around with you.
- Even if the cardboard gets destroyed, you wouldn’t mind.
The best type of cardboard for painting is the double-wall or triple-wall corrugated cardboard. You may already have it staked in your basement. For abstract painters, you could easily use large cardboard by cutting out a piece out of the box that came with your refrigerator.
Some Cardboard Preparation Best Practices
Cardboard is not a suitable material to be painted on, hence it has to be treated and prepared. It may be hard to believe that although being an unsuitable substrate, cardboard has been used even by legends to paint on. Before any kind of painting on cardboard, it has to be primed and prepared. The purpose is a create a layer between paper and the paint so that it doesn’t soak in and damage the substrate altogether.
Here are some cardboard preparation best practices:
- Make sure the cardboard surface is free from dust. Wipe off the cardboard with a tack cloth, even if you don’t see any dust visible to you. If you skip this step the dirt on the cardboard surface would prevent the primer to adhere, which will result in peeling.
- Coat the cardboard with latex primer using a polyester paintbrush. Use multiple thin layers of primers on both sides and let it dry in between each application.
- Use a dry brush to paint on your prepared cardboard and just like applying primer, use multiple layers of paints. Finish your painting layer by layer, instead of doing it in one go.
Applying Varnish to Your Painted Cardboard
Many painters would seal their painting by finishing it with a varnish layer. It leaves a shiny and glossy surface which not only looks great but makes your painting weatherproof.
There are various types of varnish that you can choose from. If you want, you can use brush-on varnish or spray on cans. Next, you can choose from an acrylic polymer varnish and acrylic resin varnish. Purchase the one that leaves a glossy finish; then apply a coat of varnish on your painting and let it dry for a few hours. The result is a shiny layer of protection on your painting, which will protect it from water and dust.
Other Types of Paints You can Use on Cardboards
The primer can be easily brushed on or sprayed on corrugated cardboard. However, you may have to apply a couple of layers for the best result, as well as giving enough time to the cardboard to dry in between. The cardboard could soak up some primer, which is why you need to apply multiple layers. There are an oil-based primer, water-based, metal enamel and general all-purpose primer. Oil-based primer would leave some circular spots after drying, and too much water-based primer will more likely soak the cardboard. Metal enamel is safe to apply if you will be painting enamel on the cardboard.
Vinyl is made from a combination of plastic and water. It is a lightweight paint and you can manage to vinyl paint corrugated cardboard if you are careful of a few things. You can choose from multiple vinyl finishes including matte and glossy finish. They do product brilliant finish and appearance to your painted cardboard and as a benefit adds waterproof and weatherproof qualities to the cardboard.
Alkyd paints are made of polyester and resin which is also composed of acids such as carboxylic acid and polyols. It has some weight to it and leaves a durable layer on the substrate. It can be non-drying, semi-drying, or drying. The Non-drying paint is used as a coating and others as paints. It can have a number finishes as well such as gloss, semi-gloss and flat. As the name suggests, all three types of alkyd leave their distinct finish. However, it does have some oil in it, which can make cardboard painting difficult.
Lacquer was once the most popular paint and can be used just on any substrate. However, it does need to applied multiple times on large surfaces and has to be sand down after each application. On the other hand, it prevents dirt and oil from damaging the substrate. It comes in resin finish that leaves a glossy appearance and matte finish which leaves a metallic appearance.
Enamel would be a more common choice among today’s painters than lacquer and also lasts longer on the substrate compared to lacquer. However, the enamel is used as a finishing coat over other paint and leaves a hard and semi-glossy layer when dried.
High Heat Paint
High heat paint is basically a coating that makes the substrate tolerant to extreme heat up to 1200 degree Fahrenheit. It is usually applied to the fireplace, heater, grill, etc. However, if your project requires the cardboard to withstand high temperatures, you can try a coat of high heat paint.
Epoxy is used as a coating or resin which sticks well on the substrate. It is made from polymers, plastics, and adhesives which gives it its distinct weight.
Latex or Liquid Acrylics
This is the most popular craft paints used in the USA. They are typically sold in 1 or 2 oz bottles and are water-based paint. It should be used after applying a layer of gesso; however, if you apply the paint directly, the cardboard would soak in most of the paint and will look pale after it has dried out. Therefore, you have to apply multiple thin layers of paint to achieve your desired appearance. These water-based paints are easy to apply and easy to clean off. The paint becomes permanent when it is allowed to dry. You can even buy gloss, semi-gloss or flat latex paints.
Watercolors and poster paints don’t work so well on cardboard. The result will be a flat appearance. You have applied multiple layers of watercolors of poster colors before getting the final result. If you want it to be glossy, you can spray paint or brush a layer of clear varnish to seal the paint.
Markers work great on cardboard. You can create the number of artwork using marker and ink alone. Both permanent and nonpermanent ink can be used on cardboard boxes. If you want to use crayons, the artwork will look great but only for a short time. To eliminate the danger of washing away or fading away, you could seal the artwork with a clear coat or varnish.
If you are creative, you can even work with chalks and pencil colors to create beautiful artwork. These dry colors don’t soak into the cardboard but don’t stick for long either. Artists typically use pastels and color pencils to give a finishing touch to their acrylic painting. You could even use nail polish colors in some of your work. Then again, to preserve the artwork, you have to give a layer of clear coat or varnish to seal the paint.
Cupboards are not exactly a good substrate to paint on. That said, today, we found out several ways to do it. It is, in fact, a thing to paint on corrugated cardboard. Next time, you have to paint your cardboard, you know what to do. However, if you are wondering you can spray paint a lot of other stuff such as resins, lacquers, rubberized coating, hydrophobic coating and a lot of other stuff on cardboard, but they are primarily for waterproofing cardboard than painting.