Chapter 7 · 1932–1945

The cold wave and the war

For thirty years the permanent wave had been a machine art: brass rods, electric heaters, the counterweighted chandelier, the long sitting in the chair. In the 1930s that began to change. A wave could be set at room temperature, by chemistry alone — no electric current, no scalp burns, no chandelier overhead. Then the Second World War rationed the metal and electricity the great machines had been built from, and the thermal apparatus became not merely old-fashioned but impractical. By 1945 the chemistry had taken the trade. The machine age did not end; it was finished.

The change a visitor to a modern salon would notice first, looking back, is the disappearance of the apparatus. Nessler's 1906 machine, Suter and Calvete's chandelier, the Mayer croquignole heater — all were devices for delivering controlled heat to hair wound on a rod. The cold wave replaced the heat with a bottle. This is the story of how that chemistry arrived, in two steps; of what it does to the hair; and of how a global war turned an option into a necessity.

A note on the chemistry before it begins. The cold wave's history is frequently muddled in the popular sources, which conflate two reducing agents and two dates. They are not the same. The first cold waves, around 1932, were sulfite-based; the commercial cold wave, around 1940–41, was thioglycolate-based. Both break the disulfide bonds in keratin, but differ in speed, smell, and commercial fate. This chapter keeps them separate, names inventors where the record supports it, and caveats where it does not.

Heat without the machine

The idea that the permanent wave could be set without the great electric heaters rested on a fact about hair grasped only once the chemistry of keratin was worked out, late in the nineteenth and early in the twentieth century. Hair holds its shape because of a particular chemical bond: the disulfide bond, a link between two sulphur atoms on neighbouring molecules of the protein keratin. These bonds form cross-bridges along and between the long keratin chains, giving each shaft its native shape and a rigidity that survives a washing. The tongs and setting pastes of the preceding centuries had altered the hair only at its surface. The cold wave proposed to do what the thermal machines had done — rearrange those bonds — but at room temperature, with a reagent rather than sustained heat.

The appeal was immediate. A cold wave required no electric current, no brass heaters hung from a counterweighted frame, and no sustained high heat against the scalp — so no heavy salon wiring, no capital outlay on the scale that had gated the trade since 1906, no burns. It removed the chandelier itself, the dangling array that had been the permanent wave's signature image and its principal hazard. The chemistry promised to do, with two bottles, what a machine had done with six hours of heat.

What stood between the principle and the salon was the reagent. The disulfide bond is robust — it has to be, to survive a washing — and breaking it at room temperature, quickly, without damaging the hair or irritating the scalp, was a chemical problem of some difficulty. The thermal machine had done the work roughly; a cold reagent had to do it selectively. Two were found, a decade apart, and the distinction between them is what the popular record most often blurs.

The first cold waves (c.1932): the sulfite generation

The first practical cold waves were sulfite-based. A sulfite or bisulfite solution, applied to hair wound on rods, would reduce a portion of the disulfide bonds at room temperature over the course of an hour or more; an oxidizing rinse would re-form the bonds in the rod's shape. The method worked — a wave without electricity, without the chandelier, and without the scalp burns that had been the trade's occupational hazard since 1906.

The sulfite cold wave is generally dated to around 1932. The names most frequently attached to it in the secondary literature are Clark and Speakman. The attribution should be stated with care: the precise roles and priority of the sulfite method's reduction to salon practice are not uniformly recorded across the sources, and the cold-wave timeline is one popular accounts compress. What the record supports firmly is the chemistry and the approximate date — a sulfite-based, room-temperature wave in the early 1930s — rather than an unambiguous paternity.

The sulfite cold wave had real limitations. It was slow: the reduction step could take an hour or more, and the waving was uneven, often under-processed at the roots. It had a pronounced and unpleasant smell, irritated the scalp, and was finicky — sensitive to the hair's condition, the room temperature, the strength of the solution. It was a proof of concept more than a finished product: it demonstrated that chemistry could replace heat, not that it could retire the machines.

The sulfite cold wave proved that a curl could be set at room temperature. It did not yet prove that a salon could set one profitably, quickly, and without complaint. That second proof waited for a different reagent, and a different decade.

Thioglycolate (~1940–41): the reagent that worked

The cold wave that made the method commercial was thioglycolate-based. The active agent was an alkaline solution of a thioglycolate salt — most commonly ammonium thioglycolate — which reduced the disulfide bonds far more efficiently than the sulfite lotions had, at a workable speed and a more controllable result. Where the sulfite wave had been an hour-long, smelly, uneven affair, the thioglycolate wave could be processed in a fraction of the time, with a more reliable curl. It was the thioglycolate cold wave that the salon trade actually adopted.

The development is most often credited to work around 1940–41, and the names attached to it in the literature are those of McDonough and Evans. As with the sulfite attribution, the priority should be stated with caution: several researchers were pursuing the same thioglycolate chemistry at roughly the same time, and the popular sources do not always distinguish invention, reduction to practice, and commercial introduction. A further name, Arnold F. Willatt, is associated in the trade record with the cold wave's commercialization. The precise apportioning of credit among them is not settled in the open record.

What is not contested is the consequence. By the early 1940s a thioglycolate cold wave existed that could be performed without any electric heater, in a salon of ordinary wiring, in a sitting short enough to compete with the croquignole machine on time as well as cost. The reagent was a consumable — bought by the bottle, used per client — where the machine had been a capital investment amortized over years. The economics inverted: a salon no longer needed a Mayer system, an Icall chandelier, or a Suter heater; it needed rods, end papers, and two bottles. The barrier to entry, which the great manufacturers had spent two decades raising, fell abruptly.

The chemistry, in brief

What the waving lotion and the neutralizer actually do is the same chemistry the thermal machines had been exploiting, unknowingly, since 1906. Hair is made largely of keratin, a fibrous protein whose long molecular chains are cross-linked by disulfide bonds — direct chemical links, each between two sulphur atoms, that lock the chains into a particular arrangement and give the shaft its native shape. Straight and curly hair differ, at the molecular level, largely in the pattern of these cross-links.

The waving lotion is a reducing agent. Applied to the wound hair, it donates electrons to the disulfide bonds, breaking them: each S–S link splits into two S–H groups (thiols). With the cross-links broken, the keratin chains are free to move, and the hair becomes pliable. The hair is wound under tension, and as the bonds open it settles into the rod's curve. Then the neutralizer, an oxidizing agent, is applied, removing electrons from the thiols and allowing the sulphur atoms to re-link — now in whatever position the rod has imposed. The disulfide bonds re-form in the new arrangement. When the rods come out, the shape holds, because the chemistry that locked it in is the same chemistry that had locked in the original shape, and it survives water exactly as well.

That is the whole mechanism: reduce, reshape, re-oxidize. The thermal machines accomplished the reduction with heat and alkali; the cold wave does it with a room-temperature reagent. The diagram above traces the sequence. It is the foundation on which every subsequent chapter — the acid perm, the digital perm, the modern bond-builders — rests. See the chemistry in full →

The war finishes the machines

The cold wave would in time have displaced the thermal machines on its own merits; the thioglycolate reagent was cheaper, faster, and safer than the croquignole heater, and the consumable economics were plainly superior to the capital-intensive apparatus. What the war did was compress that displacement into a near-abrupt one. The Second World War placed the thermal machine's two indispensable inputs under rationing: metal, and electricity.

The chandelier machines were built of brass, copper, and steel — the very metals wartime munitions production claimed first. A new Mayer system or Icall heater required materials that, from 1942 in the United States and earlier in the European belligerents, were directed toward the war effort by allocation and price control. Replacement parts grew scarce; new machines almost unobtainable. The electricity that ran the heaters was rationed in turn — current was a strategic input, redirected to factories and, in the European theatre, subject to blackout that made a sustained heat treatment impractical.

The cold wave asked for neither. Its rods could be made of materials not under war allocation; its reagents were chemical, not metallic; it drew no current from a grid under strain. A salon that adopted the cold wave during the war could keep offering the service through the rationing; one that depended on the thermal machine could not. The war years shifted the trade's default method toward the chemistry that needed none of the rationed inputs. The great machines did not vanish overnight — the croquignole heater would linger in conservative salons into the 1950s — but the trajectory was set.

There is an irony worth registering, because it is structural. The croquignole patents — the Mayer estate, the Philad Company's enforcement campaign — were being dismantled in the American courts in exactly these years. RE 18,841 was held invalid in 1940, affirmed in 1942; the judicial sale of the reissue followed in 1944. The machine those patents had protected was passing into common use at the precise moment the war was rendering it obsolete. See the patent wars in full →

The trade adopts the cold wave

By the end of the war the cold wave was no longer an experiment or a wartime expedient; it was becoming the trade's norm. The thioglycolate reagent had proved itself reliable for routine salon use, the consumable supply chains had been built, and a generation of operators had been trained in the reduce-reshape-oxidize method rather than the management of the chandelier. The barrier to offering a permanent wave — once a capital investment in a machine — had fallen to the price of a kit.

The consequence was a rapid expansion of the permanent-wave market and a corresponding decline of the machine manufacturer. The names that had dominated the inter-war trade — Nessler's successors, Icall, the Mayer-Realistic network — did not lead the chemical era; the chemistry was supplied by new firms, the cosmetic-chemical houses, whose business was the bottle rather than the apparatus. The Mayer firm itself, stripped of its patents by the courts and its apparatus by the war, pivoted from hairdressing; its successor survives, under the inherited name, in heavy industry.

By 1945 the cold wave is the trade's direction of travel. The machine age is not yet over — the great heaters will linger in conservative salons for another decade — but the chemistry has the economics, the convenience, and the momentum. The next chapter is the machineless one.

The permanent wave that emerged from the war was a different thing from the one that had entered it. Where the thermal wave had been a capital-intensive, specialist service, the cold wave was consumable-driven and broadly teachable. The route from the salon chair to the home dressing-table opened in these years, and the next chapter follows it: the machineless era, in which the cold wave reaches millions of households.

Sources & further reading

• Naivette, Inc. v. Bishinger, 61 F.2d 433 (6th Cir. 1932) & National Hairdressers' and Cosmetologists' Association v. the Philad Company, 34 F. Supp. 264 (D. Del. 1940, aff'd 3d Cir. 1942) — the croquignole patent cases whose invalidation of RE 18,841 (1940) and judicial sale (1944) frame the apparatus estate's collapse in the same years the cold wave displaced the machines. Full case history →
• Robbins, C. R., Chemical and Physical Behavior of Human Hair (5th ed., Springer) — the standard reference on keratin structure and the disulfide-bond chemistry that the waving lotion (reduction) and neutralizer (oxidation) exploit; the reduce-reshape-reoxidize mechanism stated plainly here rests on this established cosmetology science.
• Wisconsin 101 / Wisconsin Historical Society, Object History: Permanent Wave Machine (object #1980.131.1) — independently corroborates the croquignole-to-cold-wave transition and the role of wartime scarcity in accelerating the displacement of the thermal machines.
• Steven Zdatny, The Politics of Adornment: The Hairdressing Profession in France — for the inter-war-to-postwar transition of the European hairdressing trade from an apparatus-based, capital-intensive specialism to a consumable-driven chemistry, where specific firm-level records are not preserved.
• Period and secondary cosmetology literature on the sulfite cold wave (c.1932) and the thioglycolate cold wave (c.1940–41); inventor attributions (Clark/Speakman; McDonough/Evans; Willatt) carried with the caveats noted in the chapter, as the cold-wave timeline is one the popular sources frequently conflate.