Pop Quiz: Why do knits get larger? pt.2

As many of you already noted, Stuart did the heavy lifting on yesterday’s quiz. Lucky me! His comment requires little elaboration on my part (thank goodness) and is a great resource if you’re having difficult to define problems down the road. Gold stars to everyone else who gave the answer I was looking for. Note I didn’t say the only right answer, just the particular problem I wanted to cover in this entry.

If you are like me in that what you know about knits could fit in a thimble, this is the one thing you should know: that improper tension and pressure in spreading knit fabrics can cause grave problems. [I cover a lot of material about spreading fabrics and even teach you how to make markers in my book. It is poor economy to not avail yourself to that.]

Consider the common rubber band. When it’s flacid, it has x width but when you stretch it, it gets narrower. Knit fabrics are no different than a rubber band. If the fabric is lain with too high a tension, it becomes narrower. If you cut out your products while fabric is in that position, the product will be wider (and shorter) once the pressure is released and the fabric relaxes.

There are a few clues that this may be in the process of happening. You may get a panic call from the contractor at the last minute because the marker is wider than the fabric. It is possible the marker was made to the wrong width so double check that first. Otherwise, it is likely the contractor’s fault for poor spreading. The contractor will want you to drop everything to get another marker very quickly -in an hour. It’ll affect your costs in many ways. Your allocation costs will increase because you won’t get as many going across. But worst of all, you’re looking at the likelihood of products with reverse shrinkage.

This is a tough problem to solve quickly. The best solution is to have the contractor re-lay the fabric (let’s hope the lay ends are folded, not cut) or let it rest quite awhile, longer than the always prescribed 24 hours. Beating it from one end to try to push the length together will help but that depends on the length of the lay. Beating is done with long cardboard tubes that fabric comes rolled on and is done pretty much as it sounds. After you get through this mess, you should probably find another contractor.

Note: It is common that this problem does not occur in the sampling stage at the factory because a small run of samples are often laid by hand and in just a single ply so you may think everything is okay for production when it may not be. This is one of those things that may not pop up until you hit production. Prevention is best, select a contractor who specializes in knits or whatever your product type is. Avoid someone who claims they can do anything.

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5 comments

  1. Marie-Christine says:

    Let me add a tip from hand-knitting. It’s a perfectly normal human urge to take one’s sample and smooth it out, to make it look nice. Wrong!! Even a gentle pass of the hand can make quite a difference in what the size of the finished object is. You should give the sample a shake and just toss it down, not smooth and stretch it.
    Just last week I had a beginner smooth out her sample repeatedly before measuring. We finally calculated that she’d have made her sweater 15cm/6″ too small this way. That is not too cool… and we’re only talking about one sweater here, not 500.

  2. Molly says:

    In discussions on lycra/viscose/or rayon mix knits, there has been mention of “dry knits” which are believed to be much better quality. Accordingly, they are supposed to wrinkle less in the wash and not pill like the smoother lycra/viscose/or rayon knits.

    I was in belief that the heavier knits (maybe referred to as dry knits) were produced with thicker fibres and a produce a heavier fabric used for more fitted styles, versus the smooth type that is very fluid and drapes well.
    Both knits produced for their different purposes.

    Can anyone add to this as I never see these knits specifically labelled “dry” or otherwise?

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