Friday, December 12, 2008
In particular, when making an Organization coat, we actually sew a "decorative" top stitch in the garment vinyl down the front opening before placing the zipper in. We then pin the zip in place (with as many pins as possible...the more pins, the less possibility for wobbly stitch lines), pushing pins horizontally only along the pre-stitched line, so as to avoid extra holes in the vinyl.
Alternatively to pining, the entire zipper -can- be Liquid-Stitched bit by bit to each edge, WITH PRESSURE then applied to the top (a book placed overnight is more than sufficient - but Liquid Stitch needs to be pressed flat as it dries.) This is to keep the zipper even on both sides as the fabric adhesive sets. The bond, once set properly, is permanent but still flexible - however, to be extra safe, stitching once more over the previously only-decorative stitch is advisable - and because the zipper has already been securely flatly with the glue, the garment vinyl doesn't become puckered or wobbly. That last sewing stage is good security so the zipper can be yanked opened and closed often.
When working with a zipper that has been hand-fused: remember that the spliced zipper should not be unnecessarily zipped before or after being secured to the garment, and high-stress bending should be avoided. Spliced zips are for occasional costume use only, and we recommend only attaching to fabric that is at least medium thick and with a slight give (such as with SYFabric's garment vinyl or real leather.) Anything that is too tight or does not stretch enough perpendicularly to the zip may cause the teeth to split on the splice. In addition, be wary when making tight-fitting coats, and be various honest with your measurements, taking also into consideration of how you bend when sitting. Also, if you choose to machine-sew in a combined zipper, do not sew where the small triply-thick spliced area is (which would break a needle.)
For any zipper used only as a decorative trim in areas that won't ever be zipped, Liquid Stitch applied inside the hem seam is more than adequate, and top-stitching is not necessary.
First, we cut off the bottoms of the zips, right in between the last tooth and the end stop. We usually use a tool called Erdi Snips, but Cutco Shears also work great. Even regular scissors work as well (though with a little bit of gnawing.)
Fray Block is then applied to seal the raw edges; Fray-Check is also fine to use instead. This is a very important step, to make sure the threads don't unravel. (The below photo shows the right side segment in two pieces - please disregard...at this stage, both sides to be connected should remain in the zipped position.)
Then, instead of just throwing away the ends, they actually will factor back into the connecting process. Since the thick polyester zipper tape has a thick grain to it, that means it has a great grip - especially if being stuck to itself. After cutting the bottoms of the now-useless endstop (which -does- get tossed), they are cut into the following funny tab-shape.
Fray Block / Check is also applied to the edges of the "join strips" so they don't unravel either.
The unusual shape of the join strips is important because the little tab must fit in between two teeth perfectly to join the zippers - rather like floss on real teeth. The last teeth from both cut-up zips can be fed right into each other, with the join strip to be placed on top of them.
We -used- to use Weld-it on the tabs here, but after doing this for a while, we have found that The Amazing Goop, though thicker, is much more effective and will have the splices be much more durable - though you'll need a small stick to get it in between the teeth of the zipper. After coating both the entire tab and the zipper tape where the tab will be placed (and letting them dry for five minutes) the pieces are then stuck together firmly. Forceps can hold the tabs down in between the teeth as it sets up overnight, though this isn't that necessary with Goop as it had been with Weld-it. This is repeated on the reverse side, directly underneath, making a little sandwich of zipper tape over the cut line.
As you can see, it's hard to tell where the tabs are glued in, even when looking at the light grey zips for better contrast here. (This is, of course, ideal, though annoying for illustrative purposes.)