Sewing Guide for VELCRO® Brand Hook & Loop Sew-On Fasteners
SLITTING (LENGTHWISE CUT) Hook and loop fasteners of woven and knit construction are subject to raveling if slit or cut in a lengthwise direction. A 1/16” selvedge is woven along both edges to prevent raveling.
PLACEMENT OF FASTENER Generally, hook and loop fasteners from the Velcro companies are not limited by directional forces and can be used in any alignment. The hook component of the fastener is harshest to the touch and is typically used facing away from sensitive surfaces such as human skin. The loop component should face textured fabrics so as to avoid unwanted engagement, or damage to the weave.
THREAD SELECTION Thread selection (size and fiber content) can not be generalized since it is dependent upon the specific application. If practical, a synthetic or synthetic core thread is recommended. However, in most applications, the thread used in the fabrication of the item is adequate. Special machine adjustments are not required. Seam strength values of hook and loop fasteners from the Velcro companies are comparable to those of any seam in the product. Where practical, please consult a major thread manufacturer for specific recommendations.
STITCH TYPE Seam strength values are directly related to thread size, fiber content, stitches per inch and stitch type. Depending on the specific application, hook and loop fasteners can be attached to achieve required seam strengths by using a wide range of stitch types.
•Single Needle Lock Stitch Type 301- appropriate for most apparel applications. 300 series zig-zag also appropriate for certain applications
•Stitch Type 400 Series Multi-Thread Chain Stitch- comparable to 300 series.
Where practical, please consult a major thread manufacturer for specific recommendations.
STANDARD ATTACHMENT - ALL EDGES
Stitch along all four edges of fastener tape to form a box stitch. Two edge only stitching
TRIPLE STITCH ATTACHMENT
Wide hook and/or loop tape widths that must endure folding should be stitched down the center, in addition to the box stitch.
Anti-peel tabs resist unwanted peel forces which occur because of motion, severe wind, bulky applications or component interference found in some product designs and uses. An anti-peel tab can be fabricated by offsetting the four-sided box stitch on either or both ends of hook and loop components.
To prevent unwanted peel lengthwise, offset the double needle box stitch to one side of the tape. The anti-peel tab effect (see section 3) can also be incorporated by moving the offset box stitch toward one end of the fastener tape.
DOUBLE ANTI-PEEL EDGES AND/OR TABS
Peel movement occurring on both sides of the closure can be resisted by sewing a double stitch through the middle of the tape. A zig-zag stitch may also be used. Space seams approximately 1/4 inch apart on 1 inch width tape; proportion accordingly on wider fasteners.
Tab extension is an effective economy measure when combined with lengths of strap or to provide tab adjustability to elastic materials. Applications which specify hook and loop fastener tapes to extend beyond the substrate material should be overlapped by approximately 1/2 inch and sewn securely with a box X stitch. A double stitch may be substituted if only a small piece of fastener
EXTRA WIDE TAPE
Heavy duty fastening which requires greater tape widths can be achieved by sewing hook and/or loop tapes side by side on the substrate. Use standard box stitch. Velcro USA can fabricate wider sewn widths of woven and knit hook and loop on special order. For extra wide hook fasteners, inquire about ULTRA-MATE® brand molded hook fasteners which are available
The diagram illustrates the many ways round/die cut hook and loop fasteners from Velcro USA can be stitched. When an anti peel tab design is required, the stitch location must be across the direction of the peel.
LENGTH ALIGNMENT FOR LONG CLOSURES - SNAPS OR TABS
To ensure proper alignment when attaching long lengths of hook and loop fastening tape, use either of the following methods. • Use snap fasteners positioned within the hook and loop tape components at each end. Very long lengths may require an additional snap in the middle of the length. • Sew hook and loop tabs across the tapes at the measured halfway point of each tape. Press the tabs together to mate.
VELSTRAP® (VST) The VELSTRAP®
The fastener is a cinch strap offering significant holding power and infinite lengthwise adjustability. It is made from a hook tape component which is attached back-to back with a standard napped loop tape. Includes a D-ring. See section 6 for proper sewing method .
General Characteristics of woven nylon hook and loop tapes
EFFECTS OF LIQUIDS
- Completely washable and dry-cleanable
- Shrinkage: maximum 3% for hook; maximum 4% for loop
- Most oils do not significantly affect closure performance
- Retains minimum 50% closure performance in water; recovers to 100% after drying.
EFFECTS OF HEAT AND COLD
- Cold improves the rated closure strength (may reduce cycle life)
- Can be sterilized or autoclaved
- Melting temperature to 400° F
- Hand ironing - up to 250° F>
- Pressing the closure together will increase the closure’s resistance to unintentional separation (opening). Vibration, over time will produce the same effect. Both actions will likewise increase the force required to separate (open) the closure.
- Cutting across the tape will not cause raveling
- Slitting or cutting the tape lengthwise may cause raveling.
WEIGHTS - THICKNESS - DIMENSION
- Weight per inch of closure 0.45g without selvedges; slightly less with selvedges
- 25 yards of 1 inch wide hook tape weighs 6.25 oz. without selvedges; 6.0 oz. with selvedges
- 25 yards of 1 inch wide loop tape weighs 8.0 oz. without selvedges; slightly less with selvedges
- Thickness of the closure is approximately 1/8 inch
- Width of tape varies with tape width and whether or not selvedges are present; ranges from a low of +/- 1/32 inch to +/- 1/8 inch
- Selvedges, when present on woven tape, are a maximum of 3/32 inch each
- For best results, mate tapes for laundering or dry cleaning
- For best results, mate tapes when ironing
- VELCRO® brand 100% nylon fasteners should be treated the same as any other nylon fabrics