The difference is that one resin type is injection molded in molds made of metal or epoxy are dimensional consistent, while the other type is generally hand-molded in relatively flexible rubber molds that allow greater variability.
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If you went to the more stable mold type, the parts would be more similar but the cost savings of using rubber molds of prototype masters would be lost.
--- In STMFC@..., Tim O'Connor <timboconnor@...> wrote:
Jeff Aley states
>> ASSUMPTION: All of the "common" prototypes are already available in plastic.
Definitely not true.
>> ASSUMPTION: It is un-economical for manufacturers to produce plastic models
>> (RTR or kits) for the "less common" cars we still want / need.
Not entirely true. Production quantities on many plastic cars are quite low but
still profitable. The question is, how much sunk investment cost do you have to
You know what plastic manufacturers call plastic? RESIN. All this talk about resin
vs plastic is kinda silly IMO. We're really talking about injection molding versus
vacuum molding. The materials, and engineering of the final product do not have to
be that different from one another. It is only the manufacture of the parts that is
different -- the assembly process of Tichy flat kits, and Sunshine flat kits, is not
different, or it at least it need not be different.
>> ASSUMPTION: Too many resin kits sit unbuilt, primarily due to "Westerfear".
Ah, but there is always the model that you DON'T HAVE yet, and must have.
>> Why doesn't somebody [Tim O'Connor?] produce RTR models made out of resin
I definitely do produce such models. They're just not for sale. :-)
>> In this discussion, I will argue that the resin RTR car only needs to be as
>> accurate as any other RTR car; similar "manufacturability" compromises can be
>> made, just as if the RTR car was plastic. The fact that it is resin doesn't
>> automatically mean that it has to meet some higher standard of accuracy.
Totally agreed. I think it's been well established that vacuum molded resin is no
guarantee of 100% fidelity to the prototype. And many injection molded models are
top notch, almost impervious to improvement (e.g. Tangent).