Fig. 8
BLEACHING AND DYEING OF PLAITS AND HOODS
The vats (which are made of wood) and the coppers are all furnished with a steam perforated copper coil at the bottom. Over this at a slight distance, so that the heated pipes cannot come into contact with the plait, is laid a perforated tray, be it of wood or copper. The plait is laid, as described above, on this tray, and when sufficiently pressed down is covered with a perforated copper lid to prevent the plait from rising above the surface of the dyebath. This is then brought to the boil and continued for sufficient time, according to the nature of the material and colour required, to ensure perfect penetration and regularity. This time may vary from even less than twenty minutes to several hours. When the desired shade is achieved, which is proved by testing, the plait is lifted carefully from the dye bath on to a crated topped carrier, similar to a funeral bier. Formerly on arriving at the drying shed the plait was put on rods and thoroughly shaken to cast off as much moisture as possible, and then hung in the air so that the drying might not be too rapid and thus render the plait brittle. Now the plan is to place the plait, when taken from the copper, in a centrifugal wringer or “hydro-extractor,” which, revolving at great speed, throws off all free moisture and leaves the plait almost dry. Placed then in a chamber with large power-driven fans, the drying process is most speedily completed.
Before dyeing, for easy handling, all plait is “strung.” Every piece of plait is received either wound up in “sticks,” as they are technically termed, or in some looped formation which allows a fine string to be easily threaded through and tied in such a manner as to form a means of either carrying the piece or of hanging it on a wooden rod. These rods are made of convenient thicknesses and length to carry the plait in the drying departments (be it in the room, or in the open air), when suspended either in the former case on trestles mounted at suitable distances, or in the latter on lines fixed to uprights and stretched across the drying area. Each lot of plait for dyeing carries a numbered wooden “tally,” the number corresponding with the dye ticket left in the office or “giving out” room. When dry by means of these tallies, the plait is collected into its original lot, and is carefully tied up in suitably sized bundles. Some plaits receive, when dyed, a “finish” of a glucose mixture which has two effects, it gives better gloss to the material and it assists in preventing the colour coming off during the manufacturing processes. These mixtures are all of a starchy or farinaceous nature, in which some substance, say “farina” itself, is dissolved in water, brought to a boil and rendered crystal in appearance before being used for the finishing process.
Some plaits are of one colour throughout, but are made with straws that have been previously dyed. Generally speaking, especially for straws, the effect is not so good as where the plait itself is dyed. There are, of course, one or two exceptions where the fibre used is very delicately plaitted into some loose design which would not retain its crispness of outline under the weight of water in dyeing and the necessary handling. Other plaits known as “Speckled,” must, from their nature of mixed colours, be plaitted from dyed straws. Of these there are coloured and natural, coloured and white, and mixtures of various colours. The dyeing of straws follows in the main the dyeing of plait, but the preparation is somewhat different. The straws, cut into equal lengths, are tied up in bundles about 5 ins. in diameter, and are carefully placed in the vat or copper in an upright position with as little pressure as possible, and when dyed are dried still in the bundle. At one time a new dyeing effect on straws was introduced, which consisted of standing the bundles upright and allowing strong dye to run through the “pipes.” This, of course, dyed the interior and some parts of the exterior, which not touching another straw allowed the dye to do its work. Water was then passed through the “pipes,” and the result when dry was a pretty mottled effect. Another fancy method of dyeing was the production of “Ombré” colours. This novelty, introduced by the French dyers, consisted of two or more colours on the same plait. It was done by means of a fine spraying machine, which vaporized a powerful dye on to an already dyed piece of plait of some lighter tint. Messrs. Lye & Sons brought out a novelty on straw plait, particularly effective on the Japanese wide patterns, which produced the same iridescent effect that is obtained on “shot” silk. This, however, was bath-dyed and not sprayed. These various bases of double tones were utilized to their undoing, for it was no uncommon sight to see manufacturers of the lower grades of hats endeavouring to produce multicoloured effects on chip plaits by pouring the prepared dye over the plait from finely nozzled watering cans! The resultant crudeness of such arrangements brought a beautiful thing into disfavour. The shade requirements of to-day include many colours that are termed “Pastel.” These are delicate, pale shades, and can be obtained only by submitting straw plait to a bleaching process previous to dyeing, but the finished article is a thing of extreme beauty, not only on the question of colour, but in its intense purity and softness. A method for dyeing plaits, which obtained considerable magnitude in Paris, but has never been a favourite in Great Britain, is that known as “Cold Dye.” It enjoyed only a small measure of success on straw, but on chip and hemp braids very beautiful results have been achieved. In 1877 Mme. Deuxbouts, of Paris, was dyeing chip plaits in this manner, which is that used for feathers, and in 1878 at the Exposition Universelle, her exhibit in this direction was superior to that shown by any other house. It is now used for dyeing crinoline and those silk plaits which would be spoiled by heated baths.
Such are the main features of dyeing, past and present, on the various plaits utilized in hat making, and in this art, for it is no less, England has shown the way to the rest of the world. To-day other countries, such as the United States, Switzerland, Germany, Italy and Japan, have achieved signal success in dyeing, in fact on some fibres a few foreign dyers are more successful than those at home. This is probably due to the careful skill of the dyer, combined with the more favourable nature of the water used.
CHAPTER VII
BLEACHING
The other section of preparatory work for plait is that of Bleaching. The early efforts in this direction were of necessity very crude, and it is probable that imitation of the process used in some other industry, rather than invention for the particular commodity, provided the primary steps in straw bleaching. Naturally, the first thing that would occur to anyone would be to wash with water, and any grower of cereals, knowing the bleaching power of the sun, would probably combine these two elements in the endeavour to produce a better colour on the corn stalks. Then some attempts would be made with a cleanser such as soap, still utilizing the sun’s rays as bleacher after cleaning. As Italy is probably the home of bleaching operations, it is not difficult to imagine that, with the sulphur bleaching effects so easily seen round the Bay of Naples and in Sicily, it was not long before the fumes of sulphur were pressed into the service. And crude as these elements are, although the processes have radically changed, they remain practically the fundamentals of bleaching to-day.