Automotive Upholstery & Interior Restoration. Fred Mattson
You’ll use the sharp wire fasteners to attach seat covers securely to the frame of the seat. Professional hog-ring pliers are essential for crimping the hog rings correctly.
Hog Rings
Absolutely the one product to keep on hand in the shop is hog rings. Hog rings are C-shaped metal wire with very sharp angle-cut ends that can pierce through materials to securely hold the material in place. Crimping with hog-ring pliers closes them. These metal fasteners are typically purchased by the pound or can be obtained in 25-pound or more containers. Hog rings are the go-to fastener for attaching seat covers to the frame of a seat. Hog rings are also used to connect Marshall springs and attach burlap and foam to the springs of the seat.
Staples
Tacks were the standard upholstery fastener to attach materials to the wooden frame of the car. Postwar cars were built out of metal, and fiber tack strips were installed to allow for the attachment of the upholstery. Staples replaced tacks because they are faster and a more efficient way to attach materials. They also cause less damage to the tacking surface than tacks.
Fastening fabric and vinyl to the car and to interior trim panels used to be done with tacks. Stapling the materials in place has replaced the older method. Staples have proven to hold better and are much faster to use than tacks.
Staples are available in many different sizes and types. The crown of a staple is the part that spans between the legs. The crown determines the width of the staple and the legs determine the size, or depth, of the staple.
Choosing the correct staple for a job is important. The staple needs to hold the material in place without the crown going through the material. Generally, a wide metal staple is used in auto upholstery because it holds vinyl and fabrics without damaging the material. If you are working with fabric, a fine wire staple works well.
Staples are made in different materials for specific applications. Galvanized and stainless steel are good choices for auto and marine use because they do not rust with exposure to moisture.
Using the correct adhesive for the task at hand saves you a lot of frustration. Aerosol cans are convenient, but they can get expensive. Foam requires an adhesive that binds it and does not harm it. Contact cement is a great all-around glue; you can purchase it in large quantities to save money.
Adhesives
Many different adhesives are used in auto upholstery and each type has a specific use. The key to getting a good bond is to have your surfaces clean and oil free. It is not the adhesive’s fault if it fails because of poor preparation, but using the correct product does matter. Be sure that you know that the parts you are trying to glue together are compatible. Some surfaces react to the adhesive you are using by melting or lifting the paint. Always follow the directions on the label of the can.
Aerosol spray cans provide the convenience of use, but the down side is the cost per can is not practical for most shops and they usually do not have the holding power required for the task at hand, especially when working with heavy materials such as carpet.
Foam and fabric adhesives are typically available in clear or red. They are lightweight and great for bonding seat foam because they do not harm or react against the foam. Foam adhesives can be found in economical 1-gallon bulk containers for brushing or spraying as well as in aerosol cans.
I have found that the most useful glue is contact cement. DAP Weldwood makes an HHR (high-heat resistant) that provides excellent adhesion for headliners and carpets. It is available in 1- and 5-gallon cans. This adhesive can be applied by brushing or it can be sprayed with a cup gun or spray pot connected to an air compressor. It is well suited for auto upholstery work and, after the glue has cured, it is usually unaffected by temperature changes.
Burlap
Burlap is a product that is said to have 101 uses; in auto upholstery it is used as a foundation component. Always keep plenty of burlap in inventory; it is used on every seat project to cover and tension the seat springs, which gives support to the cotton and foam materials that pad the seat.
Burlap is made from the fibers of the jute plant and is a durable and strong natural material that is the main foundation material for covering and tensioning springs in every car seat. This material is one of the items you should keep in inventory. Because of its low cost, it is best to purchase it by the roll.
Burlap is a strong woven material that is available in natural jute and synthetic fibers. Most auto trim suppliers offer both types of burlap for sale by the cut yard, but because of its low cost it is most economical if purchased by the roll.
Cotton
Another must-have in the shop is cotton for seat padding. Real cotton is graded on the purity of the processed product. It has seeds, stems, and other debris in it and processing real cotton is cost prohibitive. Before the use of cotton, upholsterers used horsehair and straw to pad furniture and the seats of cars. Modern cotton is a synthetic blend of cotton fibers and spun polyester. It is much cleaner and easier to work with than the natural cotton batting that once was used. Synthetic cotton is sold by the pound and your best value is to buy it by the half bale (3 rolls).
Synthetic cotton batting is used to pad the cushion of a car seat and it is available in rolls. When purchased from an auto trim supply house, cotton is sold by the pound and is put up in rolls for convenient use. This product is easy to use and well suited for the auto industry.
Denim
Upholstery denim is a tightly woven fabric that is a durable and low-cost material that is high in strength. Denim is used primarily to save money in auto upholstery by substituting it for the expensive cover materials that do not show, such as for listings, stretchers, and filler panels. Many colors and widths are available. I usually have two neutral colors on hand to complement the project that I am working on at the time.
Often used but never seen, denim is used in auto upholstery to make listings and panel fillers, saving money on seat cover material that does not show. The durable nature of denim is well suited for upholstery because it is a strong low-cost material.
Muslin
Muslin is a low-cost, lightweight, woven-cotton fabric that is used as a cover material for seat padding and it is also a common sewing backer that can be added to the back side of sew foam to hold the stitching when pleating an insert.
Muslin can be purchased in rolls or bolts (flat folded). If you purchase a bolt of muslin, I suggest that you unfurl it and put it up on a roll to relieve the wrinkles. It is also much easier to work with when it is flat and smooth. Muslin is available in many different widths as well as bleached or unbleached. Bleached muslin is much whiter than the unbleached, which is a natural off-white in color. Another difference is the thread count of the material; it can be higher in the bleached version.
Cotton muslin is a commonly used backer material for sewing and pleating seat inserts. Its lightweight nature does not cause wrinkling of the top material and it provides a solid foundation for sewing, which keeps the stitches from pulling out.
Some trimmers use muslin for patterning or mocking up a seat cover because the material is so inexpensive.
Cheesecloth
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