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Structural Maintenance and Care of Finishes Will Prolong the Life

19th December 1947
Page 43
Page 44
Page 43, 19th December 1947 — Structural Maintenance and Care of Finishes Will Prolong the Life
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Which of the following most accurately describes the problem?

of the Commercial Vehicle Body in Times of Difficulty in Replacement

How to Make Bodies

LAST LONGER

THERE was dever a time in which it was more important to care for vehicle bodywork by every means available. New bodies are in woefully short supply, and the old ones, which would mostly 'have been scrapped tong ago, have to

work harder than ever. • . Structural maintenance, although partly a skilled job, requiring the services of the all-too-rare craftsman, is largely a matter of sound commonsense and adequate vigilance. How simple it is to go around tightening nuts and bolts on bearers, etc., and taking • up a turn or two on screws, and yet how often such attention is neglected! •

Even if it demands the removal and replacement of trimmings, this can usually be done by the average mechanic. Elementary maintenance of this nature also discloses fractures, corrosion, rotting, etc., which might, if allowed to go farther, demand far more extensive repairs.

Thorough cleaning is also an important part of maintenance, and is fat from being simply a beauty treatment. Conscientiously cleaned vehicle ',bodies last far 'longer than those left to their own devices, and are a better advertisement.

Wet or Dry Clean ?

There is always a certain amount of controversy as to whether the cleaning should be wet or dry. There is good and bad in both, however, and circumstances often dictate which method must be used. Dry cleaning means that paintwork deteriorates quicker, and this may lead to corrosion of metal and rotting of wood, whilst wet cleaning, if not followed by careful drying, may lead to similar effects. Particular attention has to be paid to effective drying in the case of interior cleaning of passenger vehicles.

An example of care in cleaning methods is provided by the case of London Transport. This undertaking's buses are washed externally with cold water and swept out internally each night, after about 14 hou1 service during the day. Every

fortnight this process is supplemented by internal washing, disinfecting and vacuum-cleaning of seats.

Bodywork generally is inspected, and minor repairs are carried out as necessary. There are further and additional inspections at 2-2-i months and 3-4 months, and at the latter period paintwork is touched up.

Every two to three years a London bus body receives a complete overhaul at the Chiswick works. It is removed from the chassis, all interior fittings are stripped, panels are removed, and pillars examined and repaired or replaced as necessary.

Thorough Interior Overhaul

Floors are also overhauled and rebuilt as necessary. Seats are removed, cleaned and repaired, routeindicator gear is overhauled, and new route blinds are fitted. The whole body is then painted and varnished. Each stage of the overhaul is subject to regular inspection.

The system employed by, the Birmingham and Midland Motor Omnibus Co., Ltd., is also of interest. There is routine inside and outside cleaning every 24 hours, usually at night, whilst every fortnight floors are scrubbed, ceilings and paintwork washed, interior woodwork, luggage racks, etc., cleaned and polished, and upholstery vacuum-cleaned and disinfected. Drivers' cabs are also scrubbed out and thoroughly cleaned. At the larger garages, machines are provided which beat and vacuumclean seat cushions.

Body panels, roofs, bonnets, etc., are washed in soap and water, whilst exposed under-parts of bodies are also cleaned. All damaged paintwork is touched up.

Vehicles are docked for inspection and maintenance every 5,000 miles. As far as bodywork is concerned, particular attention is paid to bearer bolts, door and window Mechanisms, seat fixings, floor traps, destinationblind gears, floor covering and budget-locks. Bodies are also inspected for accident damage, loose Darts, projecting screws, nails, etc. The " Midland Red" has found that bodies can be kept in service satisfactorily for about 2i years between complete overhauls, provided that they are given a light overhaul and are repainted externally every 15 months.

A light overhaul consists of minor repairs to body panels, upholstery, etc., flatting of exterior paintwork, repainting one coat and revarnishing. The work involved in a complete body overhaul is much more extensive, and depends largely on the age and condition of the body.

Effects of Labour Shortage The serious nature of the problem is indicated by Red and White United Transport, Ltd., the group engineer of which says: "No practical, inexpensive way of cleaning public service vehicles has yet been found. We have had experience with automatic washers and have used the products of oil and paint companies, but it does not alter the fact that application of these, with labour at its present high cost, makes cleaning

a very serious problem." , The company, therefore, cleans its buses in the Old-fashioned way with hose pipe, soft brush ,and ordinary water. Clensel is used extensively for the interiors, and at some depots there is a large tank below the wash to collect rain water from the roof, providing softer water and easing the strain on the mains.

For interior cleaning the company uses Sturtevant portable and fixed cleaners, but again the trouble is labour and operation.

Some interesting information on bus cleaning is contained in a report by Manchester Transport Committee, which proposes to instal a washing plant for exterior cleansing at the Northenden bus garage. The plant comprises a superstructure containing eight vertical and one horizontal motor driven rotating wipers, which automatically clean the sides and roof of a bus as it passes through.

Water for washing the sides and roof is sprayed at low pressure on to the wipers from vertical and horizontal spray pipes. No special skill is required to operate the plant. The use of low-pressure sprays has the advantage over the manual cleaning method, employing high pressure water, of reducing the possibility of timber. rot and metal corrosion. The front and rear of the vehicle has to be cleaned manually immediately after it passes through the plant.

Manchester's buses are at present washed by • manual brushing and high-pressure sprays; each vehicle being cleaned three times in a week.

It is estimated that the installation of the plant it Northenden garage would enable the number of cleaners to be reduced and. the vehicles to be

washed daily. .

The estimated annual cost of operating the. washing • plant is, including debt charges, £1,756, compared with £1,833 for the present manual system. The initial cost of installing the plant is expected to be about 17,000.

Synthetic Finishes.

The views of a protninent•' paint manufacturer on the question of nonstructural maintenance a r e .o f

interest.. '

_ Thus, Paripan, .Ltd., Sherwood House, Piceadilly Circus, London, W.1, states that, in addition to washing and leathering, the synthetic resin finishes commOnly used to-day benefit from judicious use of the pro-. prietary polishes containing wax and a very mild abrasive., Besides removing greasy marks and "traffic stains,

chalking "—the gradual breakdown Of the film—is dela34d.

A satisfactory polish will be Obtained only on a finish Which is sufficiently hard,such as matured synthetic-resin enarpeL Thus' only wax .should . be used to polish a " long " oil (natural resin) varnish or enamel. The varnish, in particular; must be treated carefully. Even wax should be used sparingly, as these finishes, when hard enough to withstand brisk polishing, are sometimes near breakdown and wax will enter the film, giving rise to rain-spotting.

Although the synthetic finish is much tougher than the corresponding natural resin product, it is not so hard as nitro-cellulose, so that polishing compounds containing considerable quantities of abrasive, used to impart the initial lustre to cellulose enamels, must not be employed.

Touching Up

On the question of touching up, it is mentioned that the edges of a bad patch should be rubbed down with 320 or 240 waterproof paper, using water and a smear of soap as a lubricant The edges of the patch must be bevelled.

The use of soap will make cutting easier and prevent the adjacent unblemished paintwork from being unduly scratched. Then* some paste filler, or cellulose stopper, should be spread over the hole with a, putty knife. When hard, the stopper, should be rubbed down with 320 Or 240 paper, using water and soap as before.

The patch must now feet quite smooth when stroked with the finger. The ball of the finger is capable of A.34 detecting an irregularity of .001 in., and if the patch does not feel smooth, more stopping must be applied. It is useless to apply paint to an imperfect surface, as the gloss will accentuate the defect.

When the stopping is quite smooth a small dab of paint is applied, and should be kept as thin as possible at the edges. If brushed, the patch will be visible, but if polished lightly when thoroughly hard, it will scarcely be detectable. If sprayed, it will be almost invisible from the beginning.

Coloured body panels are more difficult because of the problem of obtaining an exact match. In this case, if repairs must be carried out, a whole panel should be painted.

Further advice comes from Jenson and Nicholson, Ltd., 36, St. James's Street, London, S.W.1. This concern says that to ensure long life of the painted surfaces, care must be taken to use good-quality materials,. from the priming to the finishing enamel or varnish. Preparation for painting is essential, care being takm to see that the metal parts are clean and free from grease, and the timber well seasoned. All joints should be painted before assembly, and no bare wood covered over by metalwork.

Each coat of paint must have its proper drying and hardening period, and the final coat should be allowed to harden out before putting the vehicle into service.

Washing of vehicles should be carried out frequently and the road dirt washed off by hose, using plenty of water. This concern says that the scouring of paintwork by using rags and water should be avoided, as this tends to break down the surface, thus allowing water and grit to get under the top coat. The application of a polishing cream after washing would lengthen the life of the paintwork considerably, it is stated.

Before repainting, the old, finish should be thoroughly cleaned down to remove all grease, and any rust should be taken off with emery cloth. Loose paint must be scraped off, and any bare wood or metal primed with a good oil primer, which should be allowed to harden.

Filler and stopper should be applied as necessary, and the whole surface faced down to a smooth uniform surface, using waterproof sandpaper and water After all moisture has been dried out the undercoating, enamel and varnish can be applied as for new work

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