How to Makes Custom Mylar Book Jackets
Mylar is a versatile material for creating protective book jackets and other custom enclosures. Because it is transparent, strong, and flexible, it can provide protection for books while keeping their covers and spines visible.
When selecting a plastic for archival applications, however, it is important to remember that not all plastics are created equally. Archival-quality Mylar is made from polyester, a stable and inert material that is resistant to degradation and does not contain plasticizers that can migrate into collection materials over time.
TALAS offers Mylar in a variety of thicknesses, available in both sheets and rolls. Thinner gauges are highly flexible and useful for sleeves, folders, and other applications requiring a material that bends easily. Thicker gauges provide greater rigidity and protection but can be more difficult to fold. For custom book jackets and similar folded enclosures, a mid-range thickness such as 4 mil offers a useful balance of flexibility, strength, and ease of handling.
In this tutorial, we demonstrate two approaches to creating a custom Mylar book jacket. The first is designed for a slimmer book and relies on folded flaps to hold the jacket in place. The second uses a thicker book and demonstrates how larger pockets can be secured with 3M tape for easier insertion and removal.
Materials & Tools
Mylar, at least 3x the width of the book and 4 mil thick (or an appropriate thickness for your application)
3M 415 tape (for the pocket-style jacket)
Pencil or other marking tool
Cutting mat (if using a knife for trimming)
Example 1: A Simple Folded Mylar Jacket
For a slimmer book, a custom jacket can be made using folded flaps without adhesive.
Begin by placing the book on the Mylar and using the book itself to determine the dimensions needed. For this style of jacket, cut the Mylar so that its height is approximately the same as the height of the book, while leaving enough material to fold around the covers and spine.
The width needs to accommodate the front cover, spine, and back cover, along with enough additional material to create the folded flaps that will hold the jacket in place.
Once the dimensions have been determined, trim the Mylar to size.
Establishing the Folds
Center the spine of the book along the middle of the Mylar.
Begin by folding the material above and below the book, using a bone folder to create clean, precise folds. Fold these margins flat behind the book for the time being.
Next, fold the Mylar around the spine and cover boards. On each side, tuck the Mylar between the cover and the corresponding side of the text block.
For a slimmer book, these folded flaps can provide enough tension to hold the jacket securely without the need for adhesive.
Checking the Fit
The fit of a Mylar jacket is important. It should sit close to the book without pulling tightly against the covers or spine.
A jacket that is too tight can interfere with opening and closing or put unnecessary pressure on the binding. A jacket that is too loose may shift around the book and allow the folds to move out of alignment.
As a general starting point, allow approximately 1/8 inch of clearance in both height and width. The appropriate amount of room will depend on the individual book, its structure, and how the jacket is intended to be used.
Once the fit is satisfactory, remove the Mylar from the book and use a bone folder to reinforce and finalize the folds. Pay particular attention to areas where the Mylar folds over itself around the cover boards.
The completed jacket can then be slipped onto the book, with the folded flaps holding the covers securely in place.
Example 2: A Pocket-Style Jacket for a Thicker Book
A thicker book may benefit from a jacket with larger pockets. These pockets can be secured with 3M tape, making the finished jacket easier to handle and allowing the covers to slide securely into place.
For this style, use the book to determine the dimensions of the Mylar. A useful starting point is to cut the Mylar approximately 4–6 inches longer than the height of the book cover.
For the width, plan for approximately three times the width of the book cover, plus the thickness of the book. This provides enough material to wrap around the spine and covers while leaving sufficient material to form pockets for the front and back covers.
These dimensions are a starting point rather than a rigid formula. The construction should always be adjusted to the individual book.
Creating the Jacket
After trimming the Mylar, center the spine of the book on the sheet.
Begin by folding the margins above and below the book. Use a bone folder to create crisp folds and temporarily fold these margins flat behind the book. These initial folds accommodate the thickness of the bookboards and establish the material that will eventually form the pockets.
Next, fold the Mylar around the spine and cover boards, tucking each side evenly between the cover and the corresponding side of the text block.
Before finalizing the folds, check the fit carefully.
The book should close easily, and the Mylar should have a small amount of room to move rather than being pulled tightly around the binding. At the same time, there should not be so much extra material that the jacket shifts excessively.
Once the fit is satisfactory, remove the Mylar from the book and use a bone folder to finalize the folds. Remember that portions of the Mylar will fold over themselves around the cover boards, so account for this additional thickness as you work.
Creating the Pockets
With the folds established, the flaps can be secured with strips of 3M tape.
Apply the tape along the folded flaps at the top and bottom of each side, securing the flaps to the Mylar while leaving an opening for the cover board. Repeat on both sides of the jacket.
The placement of the tape is particularly important: the adhesive should remain isolated from the book. The cover board should sit above the margins created by the initial folds, preventing it from coming into contact with the adhesive when the book is inserted.
Inserting the Book
To insert the book, gently fold the front and back covers backward, away from the text block, and slide each cover into its corresponding pocket.
Do not force the covers into the pockets. If the fit feels too tight, remove the book and adjust the folds rather than putting pressure on the binding or deforming the Mylar.
Once both covers are seated, the book should close easily. The finished jacket should remain secure while still allowing the book to open and close without unnecessary restriction.
Choosing the Right Mylar
The appropriate Mylar thickness will depend on the application.
Thinner Mylar is flexible and easy to manipulate, making it useful for sleeves, folders, wraps, and other applications where frequent folding is required.
Thicker Mylar provides increased rigidity and protection, but requires more effort to fold and may be better suited to applications where structural support is more important.
For folded book jackets and similar custom enclosures, 4 mil Mylar provides a useful balance between flexibility and durability. When working with an unfamiliar book or construction, it is worth considering how frequently the jacket will be handled and how much structure the finished enclosure needs.
Mylar is available from TALAS in both sheets and rolls, providing options for everything from individual custom enclosures to larger-scale projects.
A Custom Fit for Every Book
One of the advantages of working with sheet Mylar is the ability to create an enclosure tailored to the individual book. The dimensions and folds can be adjusted based on the thickness of the boards, the structure of the binding, and how the book will be handled.
Whether using simple folded flaps on a slimmer volume or larger taped pockets on a thicker book, the goal is the same: create a jacket that protects the book without restricting its movement or putting unnecessary pressure on the binding.
Taking the time to establish a precise fit is one of the most important parts of the process. A properly fitted Mylar jacket should feel secure without feeling tight, and should provide protection while allowing the book to function normally.
