The Preparation of Plantation Rubber

Before proceeding to deal with defects in the rubber as it is put upon the market a brief account will be given of faults which may be noted in the preparatory stages.

DRYING-HOUSES FOR CREPE.--It has already been shown in the previous chapter that one type of drying-houses--viz., that over a factory--stands condemned, except for the drying of...

moderation in lubrication, and supervision. The machines should be inspected every day, and once a week rolls may be swabbed down with a 10 per cent. solution of caustic soda ap...

NO. 1, OR FINE PALE CREPE.--Considering first the preparation of the highest grade, fine pale crepe, it must be stated that the difficulties attached to the process are generall...

AIR-DRYING OF CREPE.--It is still the prevailing custom to air-dry crepe rubbers. A few estates, it is true, have artificial driers installed, and in some necessary cases others...

We have already explained that, until recently, rubber was not used in the unvulcanised condition, but that the excellent physical properties of plantation rubber have made this...

PALE SHEET.--The first form in which plantation rubber was prepared was as "biscuits" or sheets. This form remained in favour for some years. The first biscuits or sheets were r...

Whether it is necessary to employ any coagulant, or whether latex should be allowed to coagulate naturally, will not be discussed at this stage. Neither will mention be made of...

TAPPING KNIVES.--The choice of a tapping knife is a subject upon which there is much divergence of opinion. This must be so because no known knife has such apparent outstanding...

Almost without exception, the agent employed in the coagulation of plantation (_Hevea_) rubber is acetic acid, or in some cases formic acid. Under ordinary trade conditions supp...

SORTING-ROOM AND PACKING-ROOM.--It is in these departments that most factory installations are lacking. More often than one cares to acknowledge, sorting and packing are done un...

The number of manufacturers of machines for preparing rubber would seem to be on the increase, and there can be little doubt that this competition will result in a continued imp...

Every year appears to bring forth some new ideas in the mode of rubber preparation. Some of them are based in principle upon the oldest known method--_i.e._, the native Brazilia...

In the foregoing chapters the methods of treating latex, coagulating, rolling and curing, or drying, have been described in great detail. These details will give the reader some...

Meanwhile opinion is growing in favour of proceeding along the line of reducing the number of plantation grades to a minimum. At present some confusion exists. Some estates make...

Broadly there are only two methods employed in obtaining the latex from _Hevea Brasiliensis_. The first is that employed in South America, where incisions are made by means of a...

RECEPTION OF LATEX AT THE STORE.--Bearing in mind the remarks in Chapter VI. on the conditions under which latex is transported, it follows that nothing but the very best and mo...

To criticise the methods of the pioneer planters of _Hevea Brasiliensis_ presents no difficulty in the light of present comparative knowledge, and to be "wise after the event" i...

GENERAL CONSTRUCTION.--On the question of general construction there is little to be said, except that buildings are now being properly designed in more permanent form than were...

PERCENTAGE OF FIRST LATEX AND OTHER GRADES.--One of the problems confronting any manager is the question of the percentage of first-grade rubber calculated upon the whole output...

On the one hand there is the school of planters who would advocate the advisability of planting up to, say, 200 trees per acre, with subsequent thinning out by selection. At the...

The tests on the raw rubber may be carried out (1) on the sample of sheet and crepe as received. For this purpose the rubber is cut into a strip, which is clamped between grips...

CLEAN WEEDING.--Intimately connected with the growth and development of the rubber tree one has to consider the conditions under which it is allowed to mature. The argument has...

GENERAL STYLE OF FINISH.--Broadly, there is no single and definite style of finish, but on the whole it may be stated that the greater proportion of crepe rubbers are prepared i...

Raw rubber--Physical tests--Vulcanised rubber--"Inner qualities" of raw rubber--Defects of crepe and sheet-- Variation in physical properties--Rate of cure--Influence of various...

Defective coagulation--Coloured surface blotches--General darkening of surface--Soft coagulum--Spongy underface--Tearing --"Pitting" of surface--Thick ends or edges--Mis-shapen...

First consideration, fine pale crepe--Standardised dilution of latex--Coagulation and coagulant--Quantities of coagulant-- Colour of rubber--Sodium bisulphite (use of)--Evaluati...

General style of finish--Dirty edges--Iron-stains--Rust-stains --Oil-marks--Trays--Dirt--Holes--Greenish and tacky streaks-- Not due to oil _per se_--Tackiness and copper--Cotto...

Pale (air-dried) sheets--Uniformity of product--Pans _versus_ tanks--The ideal tank--Modern installations--Care of tanks-- Standardised dilution of latex--Variation in dimension...

Choice of coagulant--Strength of acid solution--Making stock solution--Quantity for use--Quantities under modern requirements--Care in mixing--Method of mixing with latex--Use o...

Tapping knives--Personal equation in use of knives--Choice of latex cups--Cleaning of cups--Water in cups--Premature (spontaneous) coagulation--Prevention of spontaneous coagula...

Drying-houses for crepe rubber--How many storeys--Ventilation --Windows--Effect of light--Effect of direct sun-rays--Hot-air houses--Smoke-houses--Various types--Ordinary smoke-...

Air-drying of crepes--Artificial driers for crepes--Vacuum drying--Hot-air driers--Michie-Golledge system--Rate of air- drying--When drying takes place--Increase in weight of dr...

Sorting-room--Packing room--Store rooms--Storage of rubber-- Need for special accommodation--Floor of store room--Local conditions--Temperature and humidity--Incidence of moulds...

Quality of metal in rolls--Nature of roll-bearings--Brass liners--Liners of alloy or of cast-iron--Adequacy of machines --Arrangement of battery--Speed of machines--Gear ratios-...

Original planting per acre--Ultimate stand per acre--Close- planting _versus_ wide-planting--When to commence thinning operations--How to select in preliminary rounds-- Later se...

Percentages of "first" latex and other grades--Early collection of latex--Transport, nature of--Light railways-- Motor-lorries--Bullock-carts--Care of transport vessels--Use of...

Acetic acid in general use--Is a coagulant necessary?--Acetic acid--Formic acid--Citric acid--Tartaric acid--Oxalic acid-- Sulphuric acid--Hydrochloric and nitric acids--Hydrofl...

Da Costa process--Byrne curing process--Freezing process-- Wickham process--Derry process--Spontaneous coagulation-- Definition of--Discussion of types--AErobic--Anaerobic-- Org...