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Dent & Ding Repair Advice
Dent & Ding repairs
Number four in a series of DIY Small - Medium Area Repair Techniques (S.M.A.R.T.)
Why do we need to do it / what we are trying to achieve
It is true to say, that we only get one opportunity to create a first-impression. Our car’s live by the same rules. It is a fact of life that roads are getting more congested, driving standards are falling, cars are getting bigger, and the space in which to drive them and park them is effectively getting less. This means it is inevitable that your car will start to pick up small dents from other people carelessly opening their doors (amongst other reasons).
Unfortunately, the very quality which makes metal so useful when constructing the car (the ductility) – is also its downfall, as it only takes a small amount of localised force to bend the metal (stretch it out a bit) and voila – a dent is created.
Regarding how well these can be repaired, think of it this way – if the metal has been stretched – can it be unstretched? Not 100%, there is scope for improvement, but you must be realistic with what is achievable with the tools you will have at your disposal.
You may have seen various rods of shapes & sizes being thrust down door window openings – I have a set of these, and they basically gather dust. Most modern cars do not have internal door panels which allow access, due to side impact beams, airbags, electrics for windows, central locking & mirrors.
You really have two choices; work from the outside and ‘pull’ the dent; or work from the inside and ‘push’ the dent. I have a compressor-driven tool called a ‘ding-puller’ (cue laughter), which works on the principle of small discs being bonded to the centre of the dent, and a negative force applied to these discs. Suction pads would operate in a similar way – but both require the paint to be in good order.
I also have specialised hammers & dollies which, once the internal door trim is removed, can ‘tap out’ the dent – these tools are available to the keen enthusiast. The hammer is used to apply force, whilst the dolly is held against the other side of the dent, to act as ballast, preventing the dent from being reversed (and standing proud of the panel). Light taps, are the way to go here. Another tip, is to look at the dent very carefully before, during and after this re-work. You will notice that there is a ‘border’ (raised part) to the actual dent; this is caused by the metal distorting upon impact. This is where the stress caused by the impact has been contained. It stands to reason (and is borne out in practice), that if this high-spotted area is gently, but firmly tapped around, this will weaken the dent, and may even be enough to straighten it out by itself (I’ve done it myself). What you would need here is a bit of dowelling with a flat tip at one end (for striking), and a rounded (but still smooth) end at the other tip (this is the business end). You want to apply force, but not have it dent the metal. You would work your way around the high spots, keeping the dowel in contact with the bodywork at all times, whilst gently tapping with a heavy rubber mallet. The idea is to gradually bring the high spot into line with the original shape of the panel, and you work in a circular motion, bringing the dowel ever-closer to (but not touching) the dent itself.
Apologies if the above is very descriptive and ‘dry’ as a result. I’m trying to include as much as possible, but obviously words can only go so far…..
I would strongly recommend getting the technique right on a scrap panel – don’t use your pride and joy as a training tool – it is so easy to over-egg this, and end-up making it worse.
This will give a satisfactory result, if care & patience is given to the task. Remember, you may still notice where the repair area was (the curse of the owner/repairer), but the casual onlooker/passenger/purchaser may not.
Hope that you find this article useful.
This job should never be complete - the day I think I've done it all, is the day I resign.
Currently in VelSatisfied's garage:
2005 FIAT Ducato 2.8JTD LWB Gran Volume, 2000 Kawasaki ZZR 1100 D7 'fullpower' in black + full GIVI & KAPPA luggage, 2007 MB R-Class 320 CDi Sport LWB uprated by Brabus to 300Bhp don't know if there's a 155mph limiter - will be fun finding out! 2004 Mercedes Vaneo 1.7 CDi Ambiente 7-seater