What Do You Know About Waterproofs?

A MAN went into a large city store not long ago and bought a raincoat. He wore it that afternoon, walking several blocks through a hard storm, and arrived at his destination soaked through to the skin, raincoat and all. He was, of course, very angry, and returned at once to the store, demanding satisfaction. The store refunded his money politely, in accordance with its policy of retaining good will at any cost, but explained just as politely that it was not actually or legally culpable — rather that the rain itself was to blame. For, the store reminded him, he had bought a showerproof coat, while the rain that afternoon had been close to cloudburst in degree.

This opens up interesting avenues of speculation. How wet is a raindrop, and when does a shower turn into rain, or rain into a cloudburst? Who measures each and how? Should an umbrella be showerproof or waterproof? And how many raincoats ought an active person to have?

Back in 1823, when Macintosh in England invented his godsend to the British, the raincoat named for him, waterproofing was quite simple. Either you bought a waterproof or you did n’t. It kept out the rain — and that was that. But increasingly man’s inventive mind has been preoccupied with the problem of developing new processes to complicate the rainy-day life of the race, and to-day a new process or a new term makes its bow nearly every week in the year.

What these terms mean or what these processes do is not very clear. As a matter of fact, if you asked even a professional buyer to list in the order of their degrees of resistance to liquid the terms ‘rain resistant,’ ‘moisture repellent,’ ‘shower resistant,’ ‘spot proof,’ and ‘waterproof,’ he would probably be lost halfway through.

Perhaps the simplest start in studying the problem is the recognition of two distinct classes under the general and misleading term ‘waterproof.’ Actually, ‘waterproof’ is a term under which degrees are not permissible. It is definitely an absolute. To say that a thing is less waterproof or more waterproof than another thing is incorrect, for if a fabric has been made waterproof it follows that the complete process of proofing against the invasion of liquid has been performed — that is, not only have the surface threads been made repellent to liquid, but also the many tiny openings between the threads have been closed. This is the exact difference between the first class of proofed fabrics, called ‘waterproof,’ and the second class, which is termed ‘water repellent.’ In the latter case there may be many degrees, governed by the type of fabric, the weave or texture, the number and size of the openings between threads — and of course, to an extent, by the type of compound used and the manner of processing. A fabric is made waterrepellent by treating only the surface threads, not the pores of the cloth.

It will be obvious that real waterproofing, in closing the pores of a fabric to liquid, must necessarily to a large extent close them to air flow, and this is the reason the completely waterproofed garment is apt to be heavy, hot, and generally less comfortable than one whose interstices allow for circulation of air. But in developing new processing for fabrics to make them resistant to water it has been found that these fabrics can be made far more comfortable to wear, and that they are practical for many more uses than just keeping out the rain. For instance, there are processes being used to make a woman’s elastic foundation garment more resistant to laundering, luxurious velvets proof against spoilage from spilled cocktails or dinner soup, a man’s shirt collar resistant to wilting, furs free of the common result of wetting — matting or delustering.

All the newfound uses of these processes are of value to consumers, but to fit the particular process and fabric to the need of the individual purchaser requires a knowledge of three things: first, the degree of resistance to liquid offered by the processed cloth; second, the effect of the process upon the future performance of the fabric; finally, the length of life of the process under ordinary conditions of use.

In regard to the degree of resistance to liquid, there is considerable latitude. The use to which the consumer intends to put the product should entirely govern the degree of resistance required. A rubber boot or a tarpaulin certainly needs waterproofing. A velvet evening dress requires probably no more than resistance to spotting. It is perfectly possible to specify exactly what the degree is in each instance; but to have these degrees of any value to the consumerbuyer a simple foundation knowledge of what takes place when a fabric meets moisture, what proofing processes do, and how the laboratory tests them, is necessary.

The story behind the term ‘wetting’ is somewhat awe-inspiring. It leaves the average human being feeling a little less sure of the character of these things we call inanimate objects. For actually wetting is a duel between two powerful natural forces resident within the two engaging surfaces. The face of a fabric is really the boundary between two other surfaces, one a body of air and the other a body of solid threads. When a liquid is spilled on a cloth the body of air is replaced by an exactly equal body of liquid, and then the battle is on. Every surface is considered to have an inherent energy or force which is called, for convenience’ sake, a tension. When the liquid surface possesses a tension or force stronger than that of the fabric surface, the liquid spreads over the fabric, with the fabric’s force grimly standing at the perimeter of the spot fighting it back. How far that liquid can spread depends largely upon how much greater its tension is than that of the fabric.

Waterproofing is no more or less than a treatment which raises the natural energy of the fabric to the point at which it at least equals the tension of the invading liquid. Then the fabric in a sense calls ‘Halt!’ to the invasion of liquid to any degree whatever. Waterrepellent processes, on the other hand, raise the surface tension of a fabric to some degree, and the amount of resistance the cloth has to wetting will depend upon the degree of tension secured.

A testing laboratory determines the degree of resistance that treated fabrics have, and an apparatus called a hydrostatic pressure machine records accurately in centimeters each fabric’s individual degree. There are as yet no official standards for any of the terms commonly used, but reputable technicians consider the following table practical and accurate:—

Resistance in Centimeters



Waterproof.50 (for one hour)

Most of the processes intended to guard against moisture spotting, perspiration, wilting, and so forth, are or should be of the 17-ccntimeter type. But you may see for yourself the wide spread there is between a fabric treated to resist showers and one to resist rain. As to how to determine what protection you require for any individual storm, that unfortunately is still a matter not determinable by any means available to the consumer — certainly not in advance.

The second thing a purchaser should know about these processed fabrics is exactly how their future performance, from the point of view of durability, has been affccted by the compound. For there are processes which deteriorate the fabric, decrease the elasticity of knit goods, affect the colors, alter the draping qualities, and so forth. No consumer can tell about any of these factors from sight or touch; but unless a purchaser does not mind playing the part of a very damp guinea pig, it behooves him to ask about them and to insist upon a guarantee that no deteriorating effect is to be expected. Some day a label attached to approved processed fabrics may give this necessary information.

The third requirement for satisfactory buying is a knowledge of how long the process may be presumed to last. Too many of the trade-marked names of these processes suggest that they are permanent. This is, so far as I have been able to discover, not true of any existing waterrepellent process. When the fabric in question is laundered or dry-cleaned, the compound is to some degree put back into solution, and each immersion plainly removes some of it from the cloth. An average of about five launderings or dry cleanings is as much as you should expect of any processed fabric, although dry cleaning is considered easier on the surface than washing. One manufacturer recognizes the impermanence of his water-repellent process, and is to be commended for making his solution available not only to laundries and dry cleaners, but to consumers as well, so that the compound may be replenished when its action has ceased to be efficient.

This danger is well illustrated by a story I heard recently of a manufacturer who created what is known as a manipulated cloth, having a very large percentage of rayon and a small balance of wool. It was attractive in appearance and low in price, and was bought enthusiastically by the cutters. After a while, however, they began to complain because the fabric met moisture unevenly when the cloth was pressed. Rayon does not react to steam in the same manner as wool; consequently the surface was rippled and warped. It was suggested to the manufacturer of the fabric that he have all the cloth processed by a reputable water-repellent method, and this he did. It worked out splendidly. Not even the cutters knew there was rayon present , at least from the behavior of the fabric under steam and pressing.

But this procedure gives rise to a pertinent and rather serious question. If the fabric is not labeled by its manufacturer to indicate that it has been processed, and if the garments are not so labeled by the cutter, and if the sales clerk does not know and cannot inform the consumer in the store, what will be the future reaction of the purchaser when the solution finally outlives its effect and the fabric reverts to its natural character?

There will be those, of course, who will feel that if the garment was inexpensive the consumer should have no complaint, even should it become unwearable after perhaps five washings or cleanings. The ethics here may be questioned, however; and it would appear, furthermore, that the retailer’s upkeep on customer good will might be considerably less if no ill will were created that must later be assuaged. Unfortunately it is too apt to be the consumers in the lower income groups, with strictly limited budgets, who are most affected. For them it is a matter of something more than fair play.