Bright green... or bright green?
As we attract new readers, including some who are new to the hobby, Stephen Paul Hardy takes a step 'back to basics', exploring the outward differences between diecast and resincast automotive models.
Stephen Paul Hardy compares casting materials.
This is not going to be a competitive comparison between a pair of models from two different manufacturers. Instead it is an illustration of the essential differences that you can generally expect to find between interpretations in diecast and resincast, using two fabulous 1/18 models that are very similar in their subject coverage.
Whilst, very visibly, both are Porsche 911 Carreras, both in Lime Green with factory option ‘whale tail’ rear spoilers, they represent cars from different Porsche model years. Our diecast representative from Solido (S1802603), released in March, depicts a 197677 Carrera 3.0.The resincast representative from GT Spirit (GT740), released back in May 2019, depicts a 1984-89 Carrera 3.2.The difference in their front fog lights is therefore, respectively, period correct for each model and the quick reference difference between them in the photos is that the GT Spirit model is the one with the additional front indicator side-repeater lamps, obligatory from 1984 onwards.
HISTORICALLY
As a sweeping generalism, diecast models are made from metal alloy components cast in machined dies. The constituent metals in the alloys have changed over the years, with modern production now usually a zinc alloy with small quantities of aluminium and copper added, called Mazak (also known as Zamak). Resincast, on the other hand, uses inert resin and filler compounds as the casting medium.There are, of course, a considerable number of commercial considerations behind both processes and a debate that makes interesting further reading on the subject can be found online (https://www.collectors-clubof-great-britain.co.uk/news/diecast-vs-resin-autoartand-spark-debate-the-issue/).
Setting the myriad of commercial considerations aside, I just want to focus on the outward, fundamental differences that are the more obvious motivational considerations for collectors when thinking about buying automotive scale models.
BITS AND PIECES
First up, is the fact that, generally, although not always, diecast automotive models tend to have opening features, whereas resincasts do not.Those opening features - doors, bonnet, boot - allow improved visual appreciation of (and access to) the interior detail.The downside is that invariably the hinges, particularly on the doors, are necessarily out of scale. Then there is also the issue of the shut-lines - the gaps around those opening features - that can detract from the overall impression of the model. Having said that, over the past few years, these gaps are
getting tighter and tighter on models
targeted at the collector's market.Very recently, the degree of accuracy on toolings and castings from some manufacturers has reduced these gaps to commendably fine tolerances.
Of course, with single piece bodies, resincast models do not come under the scrutiny of shut-lines. Their counterpart, however, is that of how crisply defined and convincing the engraved lines are that represent door edges.Admittedly this issue then also applies to any small detailing on either type of casting when it comes to small non-opening features such as fuel tank filler flaps.
Before we leave the general subject of working features, most 1/18 diecasts have moveable - or posable - front wheels, often linked to the steering wheel and therefore ‘steerable'. The norm with resincasts of all scales is that all the wheels are set fixed in line with the body centreline.The main difference from a display point of view is that posable front wheels just add a little bit of variation and realism to the display cabinet (and photo-shoots).
GLAZING OVER?
Before we get to interiors, there is the issue of glazing. Again, falling into generalisations, diecast models are normally fitted with hard, injection moulded, polystyrene-type plastic glazing, whilst resincasts feature thin sheet, celluloid-type, materials.
Looking at the diecast side first, details such as window frames and heated rear window elements tend to get included into the injection mouldings.The benefit of this type of glazing is that it is robust and increasingly now overprinted to accent raised details.The downside is that it can be slightly opaque and is generally fitted into the body shell using small lugs that can be visibly intrusive.
Turning to the resincast glazing, whilst the thin material gives a good transparency and therefore less obscured view of the interior, it is prone to flexing and minor buckling.This means that when it catches the light, fails to give the solid, hard glazed, feel conveyed by glass in real life. On occasions, the light refraction of that buckling can generate iridescence. Window rubber surrounds, quarterlight frames etc., tend to be replicated by printing them onto the glazing sheets.Whilst this produces exemplary representation of heated rear window elements, the lack of 3D relief on other details tends to look very much what it is - a 2D substitute. More recently, some manufacturers have started to rectify this by adding filigree layers of detail onto the glazing sheets, giving a much more authentic feel, but does not overcome the general issue of the flimsiness of the base glazing sheet.
TAKE A SEAT
Arguably, at one stage, resincast models specifically for the collector's market generally had the edge over diecasts in terms of the amount of authentic detailing they incorporated.The gap is closing fast and is most evident when it comes to the interiors. As 1/18 diecasts became more numerous, interiors remained very much a matter filled by single colour plastic mouldings that looked, well, plasticky! An issue, though, that has been increasingly rectified of late. Resincasts, on the other hand, from the outset delivered textured, detailed interiors that are now both extensive and intensive in their authenticity.
YOUR CHOICE
I think the accompanying photos very adequately illustrate that both die and resincasting can deliver superb models. In the end, preference is very much a personal matter. For me, it is a case of the subject and the quality of modelling that matters, not the material that the model is made from. I'll take both the bright green and the bright green, because the limited stocks are very nearly gone. DC