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Hidden rust menace can be beaten

5th May 1978, Page 30
5th May 1978
Page 30
Page 31
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Page 30, 5th May 1978 — Hidden rust menace can be beaten
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Which of the following most accurately describes the problem?

RUSTING is probably the biggest single factor affecting both the length of service life and eventual resale value of a vehicle. It is in-. sidious, creeping into hidden box sections and slowly rotting them away from the inside out.

From the outside a vehicle may look immaculate with its shiny, painted bodywork, but under the skin there could be serious corrosion which may be almost impossible to correct.

Local authorities don't help. During the average winter they spread between one and oneand-a-half million tons of salt on to the roads. This rock salt clings to the underside and the chassis of a vehicle and proceeds to rot them away.

Damage to the painted outer surfaces is often caused by stones and this gives the salt a chance to get to grips with the metal underneath.

Salt, of course, isn't the only problem. Most vehicles have built-in water and dirt traps which inevitably hold moisture.

Drain holes in the bottoms of doors are often too small and thus become quickly blocked, Here the water, which inevitably finds its way in, lays and causes the damage.

Door sills, particularly on small vans, are another vulnerable area. They, too, usually have drain holes to allow any condensation that builds up to run away. Again they can become blocked with road dirt and start a build-up of water. Every single panel seal and joint is a potential harbourer for dirt and water.

Wheel arches are notorious mud traps which hold moisture near to the metal parts long after the roads themselves have dried out. For this reason it is important to wash the vehicle regularly both on top and underneath.

Waxing, too, is worthwhile as it can displace the droplets of water which remain in the joints. Additionally the wax acts as an extra barrier against the elements.

What more can be done to revent rust from forming in the first place or if it's too late how Can rust be eliminated? CM has been looking at what's available for operators to protect their vehicles and has been asking an experienced professional repairer how he tackles the task of getting rid of the rust. Until the late Sixties the only form of extra protection available for the vehicle owner was underseal. This rubberised coating was applied to the underside of the vehicle either by spraying or by hand. In the former case it simply covered the areas that were clearly visible.

By hand it was possible to reach some of the more inaccessible parts, but even then absolute protection couldn't be guaranteed. Nevertheless, underseal is even now a fairly cheap method of ensuring at least some protection. Not only does it stop rust, it also insulates the underside from the effects of stones and helps to keep the interior of the vehicle quieter by reducing drumming.

There are a number of manufacturers of underseal, such as Dunlop; and the D-IY man can buy his underseal in reasonable quantities from accessory shops, such as Halfords. Before applying the underseal, especially to an older vehicle, it's essential to ensure that all traces of dirt and moisture are removed. If the vehicle is to be steam or highpressure cleaned on the underside, leave a day before applying the underseal. If possible the vehicle should be kept in a warm, dry place so that the surface will be free from dirt or grime. Undersea] will not ad here to dirt or grease.

As a further protection coating of red-lead or sim paint will also help.

The really keen do yourselfer can stop some of rot in the doors by removing trim panels and daubing uric seal on the inner side of outer door skin. By making s there's plenty on, especiall} the bottom, water will run the surface. Care must be tak though, that the essential dr holes are left unblocked.

If it's decided that thr holes are inadequate larger even more holes can be serted. However, the expo! edges of fresh holes must protected with either plenty paint or underseal. It's of easy to forget about other hc which are drilled in a vehicle radio aerials or other ancill equipment. Left unprotect these will be the nucleus o rash of rusting which will sc spread.

Rubber grommets or e‘ filling compound will slow process down, but it's bet once again to paint or unders these exposed areas.

An important point witt vehicle that's been undersea is to make sure that the unc seal is maintained in good c, dition. Check the undersi regularly and if any areas flaking off they should scraped off and re-sealed. regular inspection of this sort thing will prevent rust from c. ting a hold. Although underseal is a vl good means of stopping r forming on the exposed areat a vehicle, it cannot reach thr hidden box sections. Here ; other sort of treatment required.

Manufacturers like ZieloE who operate treatment statio and Cadulac offer a compli service. Box sections which ; inaccessible are drilled, fill with a special chemical rust p ventive and them grommet to stop the rot.

Using manufacture drawings the sealant is forc into every nook and cranny. the case of Ziebart the sal material is used on the und side of the vehicle too.

Special tools are used, su as lances, to spray the matei into box sections. This sort treatment is excellent for ni vehicles which haven't had t time to attract any rust. Ho ever, it is still possible to gi some protection for older vehicles although this is on a more limited scale.

Professional approach

So much for stopping rust Defore it starts. Once it has taken -told the problem becomes greater.

To see just how a professional repair organisation counteracts the creeping menace, CM visited Twyford Commercial at 489; 499 Jarrow Road, London SE1 6 3JR.

Twyford Commercial has been in the business for a number of years, operating both its own haulage fleet and latterly recovery vehicles. It also undertakes mechanical and body repairs and so is well experienced in all aspects of vehicle use.

According to Douglas Twyford, managing director, the remedy is a simple one where

rust is in evidence, either as the .result of fair wear and tear or damage, the affected section is 'sanded down to sound metal, and then a zinc chromate primer is applied.

When dry the undercoat can be added followed by the top ,coats. In some cases where the rust has come from behind a panel or alternatively has penetrated too deeply, it may be possible to fill, Where the rot is very bad or if the section concerned is a loadbearing member it is is often a more satisfactory solution to replace it all together. In any event, all the rust needs to be removed.

Aluminium is now used extensively in the construction of commercial vehicle bodies. It does not readily corrode even if left unprotected in its natural ,state, though a thin layer of aluminium oxide forms on the surface of the panel.

It is not porous so it acts as a protection to the metal beneath. As with steel, though, the crevasses need to be protected with a thick layer of paint. In contrast the oxide, which forms, in a similar manner, on a steel surface is porous. Acting as a sponge it brings the water con

tact with the good metal underneath.

Where nuts and bolts become encrusted there are any number of proprietary brands of freeing agents which can be used to disintregate the rust. But the important point here is to remove it once it has done its job and apply a lubricant which will also act as a barrier so that the nut and bolt will come undone easily on the next occasion they have to be slackened off.

Regular attention is the only lasting solution. When we visited Twyford Commercials we were shown a double-decker bus in prime condition still use by the Matchbox compan Even though it is now 30 yea old there were very few signs serious rust, which must I attributed to regular attentic and to the numerous layers paint that had been applied ov the years.


People: Douglas Twyford

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