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.

REDUCTION CARRIED TOO FAR.--However desirable it may be to diminish the number of grades, it must be pointed out that diminution and simplification are not necessarily synonymous terms in this matter. It is well known that on estates where the earth-rubber is only brought in at lengthy intervals, say of a week, the resulting crepe is sometimes very tacky. This is only natural, and is due to the prolonged exposure to the sun's rays. With the improved machinery now at our disposal, and with the increasing attention which will be given to the lower grades in the future, it is possible to prepare from average bark-shavings crepe free from bark, and of quite a good colour. Where trees are not "scrapped" before tapping, there would seem to be no objection to amalgamating the rubber obtained from the bark-shavings with the No. 1 Compound crepe; and it would be a distinct danger and possible loss if this good rubber were to be mixed with earth rubber. The liability of the latter to become tacky is well recognised; and if possible it should be maintained as a separate grade, in which it would be permissible to mix only rubber obtained from actually dry shavings from "scrapped" trees, or heavily-oxidised scraps which have been rejected from other grades.

SHEETS.--Broadly there are no fine distinctions to be made at present in the grading of smoked-sheet rubber; it is either No. 1, or if any so-called defect is visible the sheets must be rejected and plainly marked as "off-quality."

Clippings (trimmings) may either be made into crepe or shipped under their own description.

RUBBER GROWERS' ASSOCIATION'S RECOMMENDATIONS.--Taking the foregoing arguments into full consideration, it would seem that, strictly speaking, the number of grades cannot be reduced to less than four at present without producing some amount of confusion.

In its handbook,[15] the Rubber Growers' Association remarks:

[15] "Preparation of Plantation Rubber," 1917.

"The fewer grades the better, and regularity of each grade is most important.

"The grading should be as follows:

"(No. 1) Fine crepe (or No. 1 sheet), made from the free or liquid latex.

"(No. 2) Clean light brown crepe, made from lumps and skimmings.

"(No. 3) Scrap crepe, made from tree-scrap.

"(No. 4) Dark crepe, made from bark-shavings, earth rubber, and the lower quality of scrap.

"Tacky rubber should be packed separately.

"_Compound Scrap Crepe._--Estates using scrap-washers should make a compound crepe of grades Nos. 2 and 3, which will make one compound free from bark and specks. All rubber intended for No. 4 should be most thoroughly washed."

Concerning these recommendations the remarks in preceding paragraphs should be studied.

CARE IN SORTING.--Whether dealing with smoked-sheet, pale crepe, or lower grades, the strictest care is necessary in sorting and grading. This work must of necessity be relegated to coolies, and they should be trained men. Instructions must be definite, and doubtful specimens of rubber should always be placed aside for the decision of the European superintendent. Any pieces showing unmistakable signs of what are regarded as defects should be stringently rejected. In the case of pale crepe, when the defect is confined only to a small area it is permissible to cut out the affected portion. Similarly there can be no objection, in the case of smoked sheets, to an occasional sheet being treated in this manner. On the majority of estates these rules are observed carefully, but some estates yet have to learn that defective pieces of rubber may not be concealed in a bulk of otherwise good quality. Samplers have often an uncanny knack of hitting upon the defective specimens, and it is entirely the fault of the estate's sorters if these pieces are submitted as being representative of the mass.

CHOICE OF CASES.--Consumers complain justly of the presence of chips, splinters, and wood-dust. It will be evident, therefore, that whatever the type of case employed the interior surfaces should be smooth, there should be no cracks or gaps in the timber, and the cases should be cleaned out before using. There remains great room for improvement in the means and method of packing, and in spite of suggested alternatives we are at present restricted to the use of wooden cases.

From comparisons of actual quality and fulfilment of the requirements indicated above, there can be no question that cases made of three-ply wood, such as the "Venesta," are in every respect superior to the ordinary wooden cases of "Momi" type. The consideration of cost and available supplies, of course, enters largely into the question, and three-ply cases are not at present so largely employed as they deserve to be.

A new type of case was recently exhibited in Singapore. It emanates from the U.S.A. and is made of a fibrous material, resembling in appearance a very stout cardboard. The complete case when assembled consists really of two boxes, one of which is inverted and slides down over the other. Packing is completed by means of stout wire, which is strained by a simple ratchet arrangement. It is claimed that from 225 to 250 lbs. of rubber can be contained. Other claims made amount to the statement that the case is practically indestructible under normal conditions of handling and shipping. A demonstration given certainly appeared to substantiate the statement fully. Rubber packed in cases of various and average type was allowed to fall from a height of about twenty feet. In all instances the wooden cases of every type were either smashed or badly burst, whereas the fibre cases were merely dented. These cases are obtained in flat sections, which, in assembling, are folded and clamped by means of copper rivets in a special but simple machine. It was pointed out that objection might be lodged against the use of copper for this purpose.

More recently there is announced a new packing case which is stated to be made from low-grade rubbers, but information is rather vague.

BAGS.--There are in local use stout canvas bags which have the advantage of being used many times, as long as they are waterproof and kept in good dry condition. Their employment for the conveyance of smoked-sheets would appear to be permitted, but crepe rubbers sent in them are often reported upon as being "massed" at the edges, and hence difficult to "sample."

BALES.--Attempts to bale rubber for the market have been frequent, but no success seems to have attended the efforts. In some quarters the failure has been ascribed to prejudice on the part of buyers, but it is the opinion of the writers that the objections to baling are, or could be, well-founded. Massed rubber often cannot be inspected properly, and hence is always open to suspicion that internally there may be unsuitable portions.

There have been several schemes put forward for winding crepe rubber on spindles so as to form a cylindrical package complete in itself. We have seen the process, and certainly the method had much which appeared commendable. Apart from other objections which might be raised, there is always the one prominent objection mentioned in the preceding paragraph.

While baling of rubber is thus not likely to suit the general market, there is no reason why, as in one or two instances, it should not be practised by agreement between producer and consumer. It is believed that "slab" rubber is shipped in bales from Sumatra to the U.S.A.

Quite recently a proposal has been put forward to revert to a simple form of baling for ordinary plantation rubber. Under this scheme wooden cases are discarded, the packing material being composed of scrap-grade crepe rubber which, it is claimed, could be put to use by the manufacturer. An obvious drawback would be evident if these bales happened to be exposed to direct sunlight or a continuous high temperature. The tackiness which might supervene would make the handling of such bales unpleasant, even if it did not affect the internal rubber.

FOLDING FOR PACKING.--In the packing of smoked sheets it would appear to be advisable to avoid, if possible, the folding of any pieces, as the objection is made that such rubber is difficult to "sample" on arrival, especially in cold weather. Sheets should be prepared or cut to such length that they occupy the full superficial area of the box, either singly or side by side.

The same remark applies to the packing of crepe rubbers, except that here we deal with units of folded rubber. Crepes are generally folded by hand, and coolies usually work to a certain dimension by means of a standard stick. The work is slow, but often gives employment, at a cheap rate of pay, to women and weak coolies.

Several machines have been invented to replace this labour. The best of these yet seen has a simple device by means of which the length of the fold is adjustable to suit the size of any packing case. It is called the "Senang" folder, and is made by the General Engineering Company (Radcliffe) Ltd., Radcliffe, near Manchester.

CARE IN ASSEMBLING.--Whatever the type of case employed, great care must be given to the assembling of parts and the final fastening. It is not uncommon to find in the operation of putting on the "strapping" that nails have been driven into the rubber. Extra bands of strapping are sometimes advised, and where these bands pass over the sides (not edges) of the case only specially short nails should be used.

All wood should be planed, and in cases other than three-ply should be of stout wood, not less than 5/8 inch in thickness. All timber used should be of uniform type and thickness.

METHODS OF PACKING.--The usual method of packing crepe is to fold the lengths to some measure of the dimensions of the case. This is done in a haphazard fashion on some estates, with the result that either space is lost or the packing is badly arranged.

Some ingenuity can be displayed in the packing of sheet rubber in order to avoid folding the sheets, which, besides increasing the difficulty of sampling, leads to loss of space. Endeavours are being continually made on estates to prepare sheet of such a size as to obtain the maximum benefit of space both in smoke-house accommodation and in packing. A few estates employ tanks of such calculated dimensions as will yield uniform sheets which pack flat and fill the superficial area of the case.

In view of the contamination which sometimes characterises the employment of wooden cases it is sometimes advised that the interior should be lined with sheets, or pieces of crepe, the ends of which are later folded over the top of the mass. In this manner it is stated that contamination is confined only to the exterior of the contents of the case.

WEIGHT OF CONTENTS.--The dimensions of average cases are 19 inches by 19 inches by 24 inches, giving a capacity of 5 cubic feet.

In these it is possible to pack 150 lbs. of crepe rubber and 200 lbs. of sheet rubber (about 5 per cent. more in cases of three-ply wood). It may be noted that boxes arrive in better condition when fully packed. The foregoing figures are not adhered to strictly. For example, some estates find it expedient to ship rubber in actual ton lots, and for this purpose pack only 140 lbs. of crepe per case, giving sixteen cases to the ton. Other estates, using presses, pack more per case than the quantities noted above. At present there does not appear to be any definite regularity in practice.

In all instances it should be the invariable rule that the rubber should be weighed before packing, and that all cases should contain uniform nett quantities of any particular type of rubber. Invoicing, etc., will thus be greatly facilitated. If these practices are followed, and the rubber always weighed on the same scales (assuming it to be perfectly dry when packed) complaints of "short-weight" should be infrequent.

"SHORT" WEIGHTS.--In some cases the occurrence of "short" weights on arrival at ports would appear to be inexplicable. It often happens that the constituent parts of wooden cases have been in stock for a considerable period. If for no other reason than that indicated below, all cases, either before or after assembling, should be thoroughly dried in the sun. "Short" weight could be accounted for to some degree by a lack of observance of this elementary rule, as it is most probable that there would be a perceptible difference in weight of the wooden case in a drier atmosphere.

(_a_) If rubber is weighed in the box, and the average tare of the case deducted from the gross weight (in order to obtain the nett weight), any loss in the weight of the timber would appear as a deficiency of rubber at the distant port.

(_b_) Whether the same effect would be produced eventually in the case of rubber which is weighed before packing will depend upon the method of weighing at the warehouse. If the rubber is weighed in the box, any observed deficiency would be attributed to a loss of weight in the rubber.