E.M. 3047 November, 1968

KNIT FABRICS FABRIC TO FABRIC BONDING L.. ta

JUN l 6 1970 "'I~HINGTON STATE UNIVERSI1'{

Knitted fabrics are supplying a demand for clothing with elegance, fashion, easy-travel features and comfort. They are adapting to as varied uses as those from sport shirt to high style womens' suits. In kind, knits seem to differ as much as the variety we find in woven fabrics·.

Filling and warp knitting are two basic methods of constructing knitted cloth, and may be used on either flat or circular types of knitting machines. Modifications for variety can then be made in either the stitches, in the machines . used, or in both. The knitted fabrics are frequently bonded.

Filling knits use only one yarn, which on a circular machine runs continuously around it, or on a flat knitting machine, alternates back and forth. Filling knits are often referred to as "single knits", and are by far the largest volume of knits.

Warp knits are made on a chain loom with one, two, or three warp yarns per needle. Each needle makes a separate chain stitch and the chains are put together by the zig-zag of yarns from one needle to another. Some looms produce tubular cloth but most warp knits are made flat. New constructions have been designed for these warp knits in recent seasons.

Double knits are made with two sets of needles, giving both the face and the back a finished appearance. Circular knitting equipment is used for double knits but the fabrics are often delivered at open width to avoid a crease or fold, that can be difficult to remove.

Wool and wool blends are most used fibers in double knits with acrylic fiber next. Cotton, nylon and polyester are much used fibers.

Many knits are easy to sew. Be sure to consider your own feeling about the garment you plan to make, whether you look for casual or for more sophis­ ticated or tailored types. Your choice of fabric and of design will have much effect on your decision about linings, handling of seams, stitch you use, thread, tape and many small considerations as you proceed.

Slightly off-grain fabrics (less than one inch) may be straightened by pulling them on the true bias. The lengthwise wale indicates the straight of the goods. It should be used for opening tubular knits and for placing pattern pieces. The fold lines can be disastrously inaccurate and should not be used as a guide any time. Chalk or a basting thread is helpful in making the rib easy to see. E.M. 3047 - page 2

It is not neces s ary to underline double knits, in many cases. A well­ fitted taffeta slip prevents double knits from clinging without changing suppleness of the fabric. Interfacing of appropriate weight should be used on faced edges.

It is well to note whether linings and other findings are completely washable if the knit garment is to be washed later. Find information from fabric labels about whether the knit has been pre-shrunk. Knit fabrics should be pre-shrunk before using.

Consider any use of bias pieces, carefully. We should not carry over habits from handling t he lengthwise and crosswise character of a woven fabric to work to be done on knits.

In sturdy firm knits , pleats have been successful. However, give par­ ticular concern even to s l i ght fullness. Simple lines are inherently best.

Turtlenecks cut in knits should be cut on the straight of the fabric so the rib of the knit continues vertically up the center front of the garment.

Fabric should be smooth and relaxed when pattern pieces are placed to be cut. Pins should be placed at right angles to the seamline to pin pattern to fabric. Pattern markings can be transferred by chalk, pins, tailor's tacks or, with care, dressmaker's carbon.

The kind of thread to use is determined by the fiber content of the knit you are sewing. Textur ed nylon thread (stretch) has the elasticity strength for a strong resilient seam. Synthetic threads are usually preferred for greater stretch than merceri zed cotton. Mercerized cotton or silk can also be used satisfactori ly.

Shorter stitches with appropriate machine adjustment of tension and stitch length give greater elasticity to seams. Use 12-18 stitches per inch on side seams or 15-20 when strain is great. A small zig-zag stitch for give is an acceptable method.

Texture and weight of fabric will determine machine needle size. For light weight fabrics, use size 11, for heavier fabrics use size 14 (medium).

A medium or loose balanced tension is most effective for greater give in the seams. Usaully a light pressure on fabric gives best results.

Stay-stitch curved seam lines as on shoulders, necklines, armholes. Shoulder seams should be reinforced with a firm tape, either seam tape or twill. (Avoid bias tape). If a waistline seam is pres~nt, it should have tape too.

Stretch loosely knitted fabric slightly when you stitch a seam with the familiar lock stitch and mercerized cotton thread to prevent breaking of seams in wear. At the same t i me, care must be taken to keep garment in shape and to avoid stretching an entire seam area. / E.M. 3047 - page 3

A chain stitch, if available in home sewing, can be used dependably, where suitable, in places such as long seams. Stitching should be "locked" at the end of the seam. Other stitches, available, may be appropriate for knits, including those for woven stretch fabric. One consideration is the lock stitch that can be adjusted to go forward two, back one and again forward two stitches.

Edge-stitching or zig-zagging back of the cut edge may help prevent the seam allowance from rolling on light, loosely knitted fabrics.

Machine overcasting (when available) can be used to give a finished look to an unlined garment. Seam all owances should be trimmed to 1/8 inch and machine overcast together. The character of the knit and the garment are an influence here. A firm knit needs no seam finish, usually.

The weight of a fabric can determine whether to use a lapped or centered zipper. The invisible zippers are appropriate for knits. Choose the weight of zipper that relates to the weight of fabric and placing of the zipper. Choose color carefully for any zipper, but note also the color of invisible zipper tab v1hen it is to be visible.

Press-on interfacing is helpful, when making bound buttonholes, to stabilize the area to be stitched and cut. When the buttonhole is finished the inter­ facing may be heated again, lifted, clipped and much of it removed.

Buttons should be sewn on with a sturdy shank. It is desirable for the button itself to have a shank too.

A garment should hang for 24 hours before marking the hem.

High-pile Knits

A pattern for high-pile knits should have simple lines, with as many seams eliminated as possible. Avoid set-in sleeves, collars and buttonholes. Pile or nap should be cut to fall in one direction, usually from the top of the garment down. Work from the back of the fabric when placing pattern, pinning and cutting. Work on one layer at a time for deep pile, using care to reverse the pattern when needed, for two sides of garment.

Pin baste seams, keeping as much pile from seams as possible.

Stitch in the direction of the pile when possible. Use medium-long stitch (8-10). When seam is finished, turn to right side and with a needle pull out as many pile fibers caught in seam, as possible. This can help make the seam less visible.

Slash and open darts to eliminate bulk, and shear pile off seam allowances.

Finger press seams and darts. Avoid steam or other use of an iron. If a lining is to be made, use washable fabric that will require no ironing.

Hems may be done by hand. * * * E.M. 3047 - page 4

Bonded Fabrics

Bonding is done by one of two basic methods:

1. Wet adhesive bonding. An adhesive is applied to the underside of a face fabric; then a lining fabric is applied, and the two are fused with heat.

2. Foam flame bonding. A polyurethane foam is heated and applied to a face fabric, which is then cooled, reheated, and a second fabric is applied to the other side of the foam. In the two heating processes, the foam is disintegrated to about 15/1000 of an inch thick.

A fabric bonded by the wet adhesive method has more drape and flexibility than when bonded by the foam flame method.

The foam flame bonding method is also called the "foam sandwich laminate", because a thin layer of foam remains between the face and lining fabric. This method is often used when the face fabric is .so light that it requires reinforcement.

Check grain carefully over all the area of the yardage you buy. Off-grain bondeds can never be returned to on-grain fabric. Do not let yourself be persuaded that the off-grain fabric will behave well for your circumstance.

Check labels to know whether fabric is washable, dry-cleanable or both. Bonded fabrics have been known to separate when dry-cleaned. Check labels to see whether manufacturer guarantees the bond. There are two solutions used to dry-clean clothing. The National Institute of Dry-cleaning has found that the Stoddard solvent is less harmful to bonded fabric than is the per­ chlorethylene solvent.

Preshrink bonded fabric, if necessary.

When cutting, lay pattern pieces on the right side of the fabric, following grainline on the right side.

Test sewing machine adjustment. You can anticipate a medium to long stitch length for the best effect.

Stay-stitch all curved and bias seams. Understitch facings for a sharp edge. Seam finishes are rarely needed as fabrics do not ravel.

Machine or bound buttonholes are satisfactory.

Linings and interfacings are often needed, even though fabric is backed. This helps prevent stretching of some bonded fabrics and can prevent seeing through some of the thinner ones.

For bondeds, either a tailor's or dressmaker's hem is suitable. Take hemming stitches into the backing only on bonded fabrics so the hem on the right side is inconspicuous. /

COOPERATIVE EXTENSION SERVICE • COLLEGE OF AGRICULTURE • WASHINGTON STATE UNIVERSITY • PULLMAN In cooperation with the United States Department of Agriculture Issued in furtherance of the Acts of May 8 and June 30, 1914, by the Washington State University Cooperative Extension Service, John P. Miller, Director