Cardboard tubes can be made to fit a broad range of products, and are made in different levels of structural strength and thickness, depending on the level of protection required. Most commonly used for mailing tubes and shipping tubes, cardboard tubes are readily available for papers, posters, documents and pieces of artwork which are able to be rolled into a cylindrical shape. These postal tubes are able to withstand the pressure and stress that occurs during transit as they are formed from a material such as high quality kraft paper. Kraft tubes are strong and are often used in shipping and packaging. Other common uses for cardboard tubes include paper cores providing structural strength to items such as rolls of fabric, paper towels or toilet paper, and electrical wires, coin banks for collecting money and donations, caulking tubes for construction projects, grease cartridges for use in the automotive and mechanical industry and paper cans which are used widely in packaging for foods, cosmetics and merchandise. Another specific use for cardboard tubing is by contractors and construction industries that use large, heavy duty and highly durable cardboard tubes, called Sonotubes®, for concrete pillar forming.
Most cardboard tubes are spiral wound and strengthened with adhesive additives. Firstly, large sheets of cardboard or paper board are cut into thin ribbons which are then coated in adhesive and wrapped on an angle around a mandrel of the desired shape. Numerous layers of cardboard can be added to the forming mandrel, depending on the desired strength of the tube. All paper tubes are measured and defined by their interior dimensions rather than exterior, and while they can vary greatly, most tubes are no longer than 48 inches in length to ensure structural integrity.

Cardboard Tubes
Cardboard Tubes – Western Container Corp.

For heavy duty applications when high strength, waterproof and resistant cardboard is needed, adhesives or interior waterproof sealing layers can be added to the tube fabrication process. The wood pulp-resin mix is formed and cured, and may be followed by further curing in an oven. While post forming heat treatments take place, the pulp and adhesives coalesce to provide a stronger product. The finished product is more durable and holds its shape better in humidity or when affected by elements of weather. These are important features, especially for the storage or transportation of products which in addition to regular transit damage, can be further damaged or ruined by elements of moisture or air.For transportation, storage or mailing of fragile items, thicker cardboard should be used. Mailing tubes are designed to be strong enough to guard against denting, bumping and breaking during transit, and therefore it is important to purchase the correct size of tube to ensure the contents are not moving around more than is necessary inside the tube. Both ends of shipping tubes are typically closed with a plastic plug, one of which is removable, but may be sealed for postal or transportation purposes, especially of confidential documents or medical and scientific products. Or, the tubes themselves may fold in and close at either end.

The measurements given to classify tubes are the interior dimensions of the tube, taking into consideration the wall thickness and closing space at each end. Shipping and mailing tubes are often stronger than boxes or other containers and the cylindrical shapes make an ideal shipping container as there are many products that it is preferable not to fold such as posters, artwork, large maps or blueprints etc. The most common ways cardboard tubes are used range broadly in terms of function, size and industry. Tubes can be coated in colorful, customizable printed paper or foil. For food processing items, product information and logos can be printed out the outside of the tube. For gift packaging and holiday themed postal tubes, colors, patterns and designs can be incorporated into the cylindrical shape.
Cardboard tubes are often manufactured from recycled paper and those made from more durable board can be used over again, making them a cost-efficient alternative to metal, plastic, glass and wood packaging. They are comparably cost-effective because cardboard materials are easier for manufacturers to cut, purchase and dispose of than most other materials. Cardboard tubes also rival plastic and metal tubes in strength-to-weight ratio, making them an ideal solution for mailing, shipping, storing and distributing almost any material. Heavy-duty cardboard tubes are difficult to dent and break, therefore mailing and shipping tubes offer superior protection from rough handling. However, cardboard is a porous material and therefore for specific applications such as those for electrical wiring or food processing, layers of non-porous material may need to be added to the interior or exterior of the tube as a barrier against moisture. Despite this drawback, cardboard tubes are tough, flexible and renewable, and therefore provide a great commercial and industrial solution to many tubing needs.