Monday, April 4, 2011

What is Wicking?

As a cloth diaperer, it doesn't take long before you hear the word "wicking" being thrown around in message boards, product reviews, and blog posts. So what is it, exactly? Well, wicking is an intricate scientific principle of 'capillary action' that, for diaper users, can be reworded in more comprehensible layman's terms; simply put, wicking is the transfer of moisture from one area to another.

A WORD WITH TWO CONNOTATIONS

Once they know what wicking is, I've often heard people pause and say, "So then, is wicking a good thing or a bad thing?"

The answer is: wicking can be both a good thing and a bad thing.

In cloth diapering, wicking can occur as two different phenomena, both involving moisture movement or transfer, one as a negative frustration, and the other as a positive asset.

THE NEGATIVE SIDE OF WICKING

Have you ever put your baby into a diaper and left the tiniest corner of fabric sticking into, or out of, the diaper cover? Perhaps the faintest edge of a prefold was sticking out of a leg gusset or hanging out at the back of baby's waist. Or, conversely, maybe a teeny bit of baby's pajamas bunched up and touched the inside of her diaper when you laid her down to sleep. If this has ever happened to you, you'll know that you amazingly and frustratingly walked in to pick up a crying, cold, and clammy baby lying in urine-soaked clothes or bedsheets. At the time, you may have chalked this up to the diaper "leaking", but chances are, if the diaper is new and well-constructed, it was wicking (or moisture transfer) that created the wetness problem, not actually a hole or flaw in a "leaky" diaper cover.

With this negative type of wicking, moisture moves along a thirsty bit of fabric (like cotton inserts or jammies) and is literally sucked down the fibres of the cloth and into the surrounding textiles. This moisture transfer can really be amazing in its efficiency, not only creating a minor damp spot where the threads touched one another, but truly creating a channel for moisture to continuously flow and escape.

Obviously, no one likes this type of wicking! So how can you prevent it?

To prevent negative diaper wicking, ensure that all diaper fabrics are well-contained within a waterproof (and wicking-proof) diaper cover consisting of some non-wicking fabrics, like PUL (polyurathane laminate), wool, or even old-fashioned "plastic pants". Don't allow even the tiniest corner of fabric to stick in or out of the diaper area, or else get ready for the floodgates to open! Remember that hidden within textiles is the perfect escape route for liquids to travel along--a fibrous highway of sorts.

Occasionally, some diapers themselves do have a construction that can contribute to negative wicking. Watch out for diapers or covers that provide some sort of connection between the inside and the outside of the cover--even the tiniest connection (such as a rolled edge, or threads stitched through all the diaper layers on a band of velcro) can be enough to enable the transfer of urine from the inside layer of the diaper to its outside environment. Another problem area can be cotton-trimmed edges or elastics that have a solid band of fabric that travels from the inside of the diaper to the outside. Oftentimes, although these diapers may have a very cute "two tone" look, moms find them frustrating to use when they seem to "leak" out onto baby clothes and bedding time and time again.

So, overall, the key to preventing leak-like diaper wicking is to ensure that anything you intend to hold urine is totally isolated within the diaper's waterproof (or water-resistant) layers with no bridge of textiles--even a few threads--leaving a route to the outside environment.

THE POSITIVE SIDE OF WICKING

Wicking, or moisture transfer, can also be a positive thing when talking about cloth diapers. Obviously, for both comfort and rash-prevention, it is optimal to reduce the amount of time that baby spends sitting in a moist diaper. Since continuous diaper changes are not possible, the science of moisture transfer helps moms out in keeping babies comfy and dry in between diaper changes.

While natural fibres such as cotton, hemp, and bamboo are incredibly thirsty and absorbant, once saturated, they stay very saturated, even next to baby's sensitive skin. Yes, they may continue to absorb and absorb and absorb (until they can simply hold no more), but they will feel wet, cold, and uncomfortable on a baby's skin as they do so. Because of this, many diaper manufacturers have begun to use wicking fabrics as the lining for diapers in order to facilitate the movement of moisture away from baby's skin and into a deeper layer of cloth. Many pocket diapers and all-in-one diapers on the market today use a synthetic layer of microfleece or microsuede as the "stay dry" layer next to baby's skin. These synthetic fabrics have been specifically designed with wicking capabilities--within the makeup of these textiles, microfibres drink in moisture and quickly move it straight through the top layer of fabric and into a more absorbant fabric (like a cotton pad) placed underneath (away from baby's delicate skin). Synthetic fabrics designed specifically to wick have next to no absorbancy--they exist only to facilitate the transfer of liquids and to stay dry even when continuously drenched with liquid.

HOW TO USE WICKING TO YOUR ADVANTAGE

In short, to create your own positive "stay dry" wicking system with your baby diapers, simply fashion a two-layer system.
1. Use a synthetic liner (like a small scrap of microfleece) as the top, "stay dry" layer of your diaper (closest to baby's skin).

2. Place this wicking layer on top of a more absorbant insert/booster/pad such as microfibre or terry towels, or folded cotton, hemp, or bamboo prefolds.

3. Of course, don't forget to contain your whole diaper system within a waterproof cover or shell to prevent the negative kind of wicking (leaking) from spreading to your baby's clothes, blankets, or bedding.
And now, with the science of wicking on your side, here's hoping both you and baby will enjoy many dry nights and deep slumbers!

2 comments:

  1. Can you use any microfleece from the fabric store or is there something specific? I'd like to create some stay dry liners for a couple of my AI2s that I use with bamboo, hemp or cotton inserts.

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  2. Hi Melissa (& Rob ;)

    Any microfleece from the fabric store should work just fine! Find something with a pattern, color, or price tag that you like best! ;)

    Just remember that microfleece is different than regular fleece (i.e. polar fleece, etc). The thick, regular type of fleece is actually very water repellant, which will cause moisture run-off or will direct urine straight back at baby. It's the microfleece that's fine enough to allow wicking through its surface down into more absorbant layers below.

    Another handy fact about making your own microfleece liners is that you don't have to worry about serging or finishing the edges in any way. Part of the beauty about fleece is that it doesn't fray when cut. So simply cut out your long rectangle shapes, and they are good to go! These liners will also work great as a barrier layer to preserve your dipes when using diaper creams that can clog the absorbancy of your normal diaper fabrics and inserts.

    Hope this helps! Good luck! :)

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