How waterproof is canvas?
When planning to explore the outdoors, snorkeling, kayaking, or fishing; waterproof outdoor gear is a necessity to keep your stuff dry. True, from fashionable clothing and shoes to sailing and home décor, many items are made from canvas. But still, you may be wondering just how water-resistant canvas is.
We at Waterproved are here to provide answers for you. Ready? Let’s dive in to how waterproof canvas actually is and if it will make a good waterproof fabric for your next adventure.
Where is Canvas Commonly Used
Below are some common uses of canvas fabric.
Sails
Although today’s sails consist of marine canvas (materials such as PVC and coated polyester vinyl suitable for outdoor use), originally, they consisted of canvas fabric. These fabrics are tightly woven, making them windproof and somewhat water-resistant. After some waterproofing treatment, they become entirely waterproof.
Tents
In addition to being windproof and waterproof, the heavy-duty canvas is an exceptionally sturdy material that doesn’t give in to tugs or stress, making it ideal for making awnings, tents, and other camping supplies.
Bags
Due to the fabric’s durability and sturdiness, canvas material is used to make various bags, including tote bags and backpacks. Like denim, upholstery fabric, and outdoor fabric, the canvas is great for making tote bags.
Shoes
Canvas is flexible and durable and combined with rubber soles that grip well on indoor surfaces, makes it the preferred footwear for basketball, hockey, and tennis players. It’s also ideal in hot weather because it allows air through to your feet.
Painting
Canvas has been popular for painting since the 15th century. When adequately prepared, it makes an excellent painting surface stretched over a wooden frame. The color glides on, and with proper application consistency, it’s possible to create a painting devoid of brushstrokes, and you can also flatten wrinkles.
Backdrops
Canvas absorbs paint well, making it ideal for coloring with textures. Also, the lightweight canvas is easy to move around with, making it popular with photographers who use it as a backdrop.
Clothing
Canvas’s durability and water-resistant qualities make it perfect for making outdoor clothing. It’s also flexible, and it lets air in, making it comfortable.
Furniture
Canvas is strong, durable, and suitable for repeated use, making it widely used for upholstering furniture.
Embroidery
Want a base for your embroidery? Canvas makes a perfect base for embroidery, such as Berlin wool work and cross-stitching. Java canvas (also known as Aida cloth), Chess canvas, Blinca canvas, and Penelope canvas are specific embroidery canvases.
Technical Makeup of Canvas
Here’s an outline of the technical makeup of canvas.
Strength
Cotton canvas is a moderately strong material with a tenacity of 3 to 4.9g/d. We can attribute this strength to the length of polymer chains, and, interestingly, it gets 10 to 20% stronger when wet.
Modulus
Because cotton fibers have a modulus of elasticity similar to that of polyester, it is easy to blend the two fibers well.
Elongation and Recovery
Cotton canvas has low elongation and elastic recovery, and bands and cuffs made from it don’t fully recover after stretching from wear and tear.
Resilience
Due to its low resilience, cotton canvas doesn’t recover well from wrinkling, which is why you must iron it after washing. The hydrogen bonds between chains break and then reform in new positions, causing it to hold wrinkles and other distortion. However, applying durable press finishes on the surface can improve resilience.
Flexibility
Cotton canvas is fairly flexible compared to other fibers. However, it has a bending resistance which hampers its durability, causing it to score lower in fineness.
Absorbency and Moisture Regain
Canvas has a moisture regain of about 8%. It has several hydroxyl groups which attract water, making it highly absorbent. That’s the reason it’s suitable for making towels, diapers, and other items where absorbency is key and why it’s comfortable to wear during hot weather.
It’s also why it dries slowly as the absorbed moisture must evaporate from the fabric. And when it comes to painting, the canvas is loved for its ability to take in waterborne dyes.
Heat and Electrical Conductivity
Cotton canvas has fairly high heat conductivity, making it a comfortable fabric to wear in hot weather. It also conducts electricity; hence it doesn’t build up static electric charges.
Combustibility
Cotton canvas is highly combustible. It will not only burn when exposed to a flame but continues to burn after you extinguish the flame And interestingly because it’s not thermoplastic, cotton canvas doesn’t melt. Instead, when exposed to dry heat (about 3000F), the fabric gradually deteriorates. It’s the reason cotton canvas turns yellowish when exposed to excessively high ironing temperatures.
Chemical Reactivity
Cleaned and bleached cotton canvas is cellulose (about 99%), with chemical reactions typical to cellulosic materials. For this reason, you cannot apply excessively acidic types to it.
Gravity
Cotton has a specific gravity of 1.54, which is higher than that of polyester (1.38%) and nylon (1.14%). Hence, cotton canvas feels heavier than fabrics made from polyester or nylon.
Dimensional Stability
When wet, cotton canvas yarns tend to swell in transverse directions, causing tension. And when these tensions relax, it causes changes in the fabric dimensions. That’s why cotton fabrics shrink after the first few washes. However, special finishes can be applied to fight this shrinkage.
Is Canvas in Its Rawest Form Waterproof?
No, canvas in its rawest form is not waterproof.
As mentioned earlier, the canvas has a high absorbency and moisture regain of about 8% (compared to nylon which is 4%). This high absorbency is due to its many hydroxyl groups, which attract water.
Also, considering its chemical reactivity, the canvas is 99% cellulose, causing it to be absorbent. The cellulose contains a negative charge making it attract and absorb water molecules (dipolar).
In this respect, canvas is a hygroscopic material since it absorbs fluids and allows them to pass through instead of resisting. And the absorption rate increases with humidity. Therefore, when you pour fluid on it, it absorbs the liquid fast, much like a sponge.
What Properties Can Make Canvas More Water-Resistant?
The following are properties that can make the canvas more water-resistant (learn the difference between water resistant and waterproof here).
Flexibility
Studies have shown that increasing a material’s flexibility and elasticity can boost its water-resistance. The research done on some suspended films showed that the films in which elasticity and thickness were more resistant to water than the films mounted on a substrate.
Interestingly, this principle is borrowed from nature. The flexibility of butterfly wings, insects, some birds, and some plant leaves surfaces improves their ability to repel water.
Weight
Increasing the weight makes a material more water-resistant.
Tests carried out on polythene composites reinforced with bamboo and kenaf showed the impact of weight on water resistance. There was a significant correlation between tensile properties and the amount of water absorbed.
Both tensile strength and ability to resist water improved when they increased the weight.
How to Make Canvas Waterproof
Although canvas has some water-resisting properties, you must make it waterproof to prevent water from seeping through it.
The following are techniques used to make canvas waterproof:
- Fluoropolymer coatings: These are blends of fluoropolymer lubricants and high-performance resins in a dry film lubricant. Upon application, a surface is protected from corrosion and chemicals.
- Silicone coatings: This is a flexible, rubbery plastic that’s an ideal sealant choice for plumbing pipes, ships, and metal-based items requiring a watertight seal.
If you’re interested in learning more, check out our full guide on how to waterproof canvas.
The Last Drop
Canvas is an excellent material that people have used for years. You’ll find it in sails, clothes, bags, and even art masterpieces. Its array of qualities make it unique and useful, just not waterproof, but with the proper treatments you can have a waterproof product for years to come.
Curious about how waterproof other fabrics are? Check out our other articles below.
