By Andrew Marsh
Engineering Director, Auto Industry Consulting Ltd
Once upon a time a highly respected UK shop owner stated that “if one can pass water, one can paint.”
The original phrase is even more offensive, but there are some important themes behind this. From the damage scoping phase through panel repair/prep and via painting to final assembly, there is a high demand for the greatest skill possible to execute the job regardless of size. Indeed that skill is all about getting the best finish or fit for the least amount of time.
The painting process is the only one that does not involve stripping or rebuilding the vehicle. Further, it is the only process where the job execution time can be very accurately forecast as it sits in the middle of the restoration process. Add to this that operatives are frequently rewarded by the number of jobs completed per hour, and we have a potential focus on volume of work than quality.
OK, by now refinishers all over the land are pretty angry, and rightly so – because things are changing.
The time for the refinishers to take centre stage is rapidly approaching. Already select OEMs have fitted carbon fibre reinforced plastic (CFRP) panels where the weave is visible though a clear coat for several model generations, but this is not common. Now we see the emergence of CFRP with thermoplastic resins which are finished with a smooth outer coat, intended for colour refinishing. But that’s not all …
We know the set-up of the paint equipment and especially the spray gun along with post-operation cleaning is vital for minimising paint consumption as well as delivering the very best finish. The issue is the panel stiffness itself, as it alters the way the paint droplets interact with and wet-out the panel.
The panel technicians are already fixated on material strength in terms of possible joining solutions and indeed it can affect the extent of the allowable repair. Now we see that extending to refinishing, since there is a very clear drive by OEMs to further reduce weight across the board in the next few years. That translates to even thinner skin panels, or skin panels made from multiple materials (typically bake hardened steel alloy, multi-layer aluminum alloy, plastics and occasionally fibre reinforced plastics) on a single vehicle. It is no longer possible to think about the body shell and bumper facias requiring different refinishing processes – it’s much more subtle than that.
Specifically for the skin panels the ultimate tensile strength will be slightly higher than for mild steel, but the reduced panel thickness means that whilst the resistance to denting is on a par it will deflect in a different way – which affects the application of paint. When we alerted a European OEM about how a recently introduced vehicle had mainly bake hardened steel alloys skin panels they were surprised – they were the Tier 1 supplier to that OEM but no one inside the product development team had associated panel material properties with the refinishing process. Amazing!
So perhaps the new way to refer to refinishers now should be “if you are a material properties expert, you can paint.”
About Auto Industry Consulting
Auto Industry Consulting is an independent provider of technical information and consultancy to the global collision repair industry which was formed by Ben Cardy and Andrew Marsh in 2011. Of the many services we offer two of our key products are:
Auto Industry Insider uses in-depth research to identify the relevant key industry challenges and their effect on the vehicle repair sector – see autoindustryinsider.com.
Ezi-Methods provides OEM based repair methods and information via our web service, now sold in the UK, USA, Australia, South Africa and New Zealand. For further information, please visit ezimethods.com