CHAPTER XII
SORTING, GRADING, AND PACKING
The question of standardising the output of our plantations is one which has occupied attention for some years, with a not inconsiderable degree of success.
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 up tree-scrap and bark-shavings together; one estate puts tree-scrap, earth-scrap, and bark-shavings into one uniform crepe; other estates have three or more separate scrap grades—e.g., lump-rubber and “washings,” tree-scrap, earth-scrap, and bark-shavings scrap. There is a movement on foot at present to try to restrict plantation rubber to three grades:
Crepes—1. First Quality Latex.—I.e., crepe made from the true coagulum obtained from the regulated coagulation of strained latex. This is a pale rubber, and may be prepared satisfactorily if the directions given in preceding chapters are followed. Naturally there must be, in all factories, some defective rubber of this grade. For various reasons the crepe may be of inferior colour, or is slightly contaminated with dirt or traces of oil and grease, etc. This defective rubber should be placed aside most rigorously and plainly marked as “off-quality.”
If a proper scheme of standardisation of latex and chemicals is followed, there should not be any such variety in shades of colour, such as was common in No. 1 crepe in the past.
Comparatively few estates in Malaya now prepare thick (or blanket) crepes in the No. 1 grade, but in such cases the same rules must be applied as govern the sorting of thin fine pale crepes.
2. Compound Crepe, No. 1.—In this it is proposed to include cup-coagulated lumps, coagulated lumps from transport vessels, skimmings, bucket rinsings, cup-washings, and tree-scrap. It has been shown in [Chapter X.] that strict care is necessary to eliminate all oxidised (dark) scraps. These are relegated to a lower grade. The possession of a “scrap-washer” is necessary if the best results are to be obtained.
On some estates the ingredients of this compound crepe, while fresh, are placed in a common jar or tank to which a quantity of sodium bisulphite (1 per cent. solution) and acid are added. The resulting conglomerate mass is cut up for working.
3. Compound Crepe, No. 2.—This grade would include the remaining lower grades—viz., bark-shavings, scrap, and earth-rubber scrap.