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2-3 Boxes

2-3.1 Use and Type

2-3.1.1 Paperboard

A paperboard box (similar to a suit box) is acceptable only for easy and average loads of up to 10 pounds.

2-3.1.2 Metal-Stayed Paperboard

A metal-stayed or stapled paperboard box is acceptable only for easy and average loads of up to 20 pounds.

2-3.1.3 Solid and CorrugatedBox Manufacture's certificate. Fiberboard

A solid and corrugated fiberboard box is acceptable for all load types up to the weight and size limits shown in Exhibit 2-3.1.3, unless otherwise specified. The box grade (bursting strength) of a box is printed within the circular or rectangular boxmaker's certificate (pictured here), which lists the box's maximum size and gross weight limits for easy and average loads. The first maximum limit reached for an item to be mailed, whether size or weight, governs the grade of box to be used.

Exhibit 2-3.1.3

Maximum Weight
(Box + Contents, Pounds)

Maximum Size (Length + Girth, Inches)

Box Grade
(Bursting Strength, Pounds per Square Inch)
Easy or
Average Load
20 N/A 67 125
40 20 100 175
65 45 108 200
70 65 108 275
N/A 70 108 350

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2-3.1.4 Wood, Metal, or Plastic

A wood, metal, or plastic box is acceptable for all load types. The box's acceptability depends on its construction, its ability to withstand shock and pressure, and its potential to damage other items.

2-3.2 Size

A box used as a mailing container must be large enough to hold the items and any surrounding interior cushioning material. If the box is too large and the items inside the box are inadequately blocked or cushioned, the items might shift in transit. If the box is too small, the cushioning might be ineffective protection. In either case, the box or items might get damaged during handling and mail processing.

2-3.3 Making Boxes

If a box of the size required for an item is unavailable, other boxes can be resized. Exhibit 2-3.3 shows how to cut a larger box down to the needed size and how to make an acceptable mailing container from two boxes of the same general dimensions by removing their flaps.

Exhibit 2-3.3

2-3.4 BandingExample of banding.

A box containing a difficult load must be reinforced with banding (strapping). The box should be banded about every 8 inches in two directions around the box. See 4-3 for more details on banding.

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2-3.5 Outer Wrapping

If a box itself is adequate for mailing, wrapping paper should not be used to cover the box. If wrapping paper is necessary, paper as strong as a regular large grocery bag (60-pound basis weight) is recommended. The appropriate type of tape should be used to close and reinforce the box. See 4-5 for more details on selecting and using tape for closing and reinforcing packages.

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