"Pool Knowledge on Plastics"
Page 65
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IT would be wrong to say that reinforced plastics have I yet proved to be a satisfactory substitute for all other : materials, as time alone can prove many of the factors which as yet remain theoretical conclusions." This was stated by Mr. N. R. Carrington-Bates, director, Commercial Motors (Harrow), Ltd., when be addressed the London Division of the Industrial Transport Association on Tuesday.
There had unfortunately been no pooling of knowledge by companies developing plastics, with the result that good, bad and indifferent moulders were producing plastics of differing qualities and prices. Care was needed in selecting a bodybuilder with adequate experience.
Intelligent labour was required for the moulding process, The cost of basic materials was high and formed about 75 per cent, of the price of the finished laminates. Development of sandwich construction could eliminate the need for body framing, leading to 'a revolution in the bodybuilding industry. This, however, would demand a high degree of standardization in body sizes and styling among operators.
Use of Machine Mr. Carrington-Bates thought that if the M.A.S. machine for producing plastics laminates (described in The Commercial Motor, July 19) fulfilled the claims made for it, the introduction of plastics bodywork into new fields would be 'encouraged. Manual laying-up left too much room for variation in quality of finished products: too much responsibility rested with the operator and not enough on predetermined specification. A machine of the M.A.S. type would eliminate much of the hazard of indifferent labour.
Claims made for the weight-saving properties of plastics could not be justified in all instances. Weight for weight, glass-fibre reinforced resin was as strong as steel, and if the strength of steel was required its weight would be matched. The, virtue of plastias was that it could be made in curved shape S more easily than metal, and thus be .conferred with • strength at less cost.
Colour-impregnated plastics were difficult to 'produce as the surfaces of the moulds had to be maintained in a highly polished condition. This added to.produetion costs, Another
factor was the need to avoid damage to coloured parts during' assembly, and in any event it was always necessary to restore the original polished surface after the bodybuilders had completed their work. An imperfect coloured. moulding had to be scrapped as it could not be made good' without too much trouble. All these factors were reflected in the price.
Few moulders have had the courage to demand an adequate price for the job, but have preferred to accept an unrealistic price and put their faith in improved knowledge and technique, eventually reducing costs. or to refuse colour work altogether." said Mr. Carrington-Bates. Furthermore, the quality of a coloured moulding did not compare favourably with one in natural finish. The addition of pigments detracted from the characteristics of the resin.
Almost-silent Cab
An important field for the application of plastics was in cab construction. An almost-silent cab could be made for forward-control oil-engined vehicles: it would also be warm in winter and cool in summer, and free from drumming. In the present stage of development, too much regard had been paid to traditional modes of construction and styling, entailing the retention of framing.
The approach to load-carrying bodies was more complex. The real difficulty to progress was the " obstinate insistence" of operators to vary body shapes and sizes. " If, in the interests of economy and efficiency, a range of standard units could be agreed upon which would be suitable for a repre sentative body of operators, it would not be difficult to enlist the co-operation of experienced moulders to develop moulds for the production of suitable units," said the speaker.
In designing a boxvan body, care should be taken to refrain from developing large sections which were expen
sive to replace if damaged.. A body designed in sections and bolted together was the best practical approach. Development costs Could be high. The plastics industry urgently needed a development corporation. There should be united and well-financed effort to develop the outstanding ' potentialities of a fine and. versatile material. •