Resin aftermarket??

Due to the molding techniques used with resin, the details can be more crisp and sharp. Things like undercut edges that really can not be done with styrene can be done in resin.

Also they make conversions to diffrent A/C or armor which are not available in plastic yet.

Manufacturing cost is also a big factor. The molds for polystyrene are hugely expensive as they must withstand high temperature and pressure of the injection molding process. Thus, it is only cost-effective if they plan on making a very large number of products.

Resin casting is more suited to make a smaller number of products, as there is no need for expensive steel molds. There is a lower initial cost to get started. But the molds wear out quickly, and thus resin casting is not cost effective for a large run of products.

It used to be that the low surface  tension of the molding resins and RTV molds made for unmatched surface detail.  However, lately, through whatever new molding technology is coming into use in new kits from major mfgs, the detail in styrene kits is matching the detail of resin.

The other advantage of resin casting is lower cost of molds, so people can offer parts that  will have as much demand- more unusual or rare stuff- offbeat options.

In armor modeling, often times the vinyl tires will adversely effect the surrounding plastic after a while. Replacing vinyl with resin will eliminate this. Also a lot of model companies use a generic looking vinyl tire to avoid licensing issues. A resin company will produce more accurate and better detailed tires.

rob  how does a vinyl tire effect the rest of the plastic?

joe

It often causes the surrounding plastic to melt. Dragon's early wheeled Soviet vehicles had this issue, Trumpeter's Chinese BJ-212A jeep had this issue and there have been accounts of Academy's M60 series tank kits (they use a thin rubber road wheel to the plastic one) having the rubber rim melt the wheel.

The issue normally occurs when unpainted vinyl stays in prolonged contact with unpainted plastic. I've taken to dipping the vinyl tire in Future floor polish to act as a barrier. Others have covered the surface of the wheel with bare metal foil where the tire would contact the wheel surface.

Car kits often have chrome plated wheels so they normally do not have this issue or might use a better form of vinyl for their tires.

The appeal of resin to me is that very small runs of unusual items are available. As an example, I'm planning to build an early M 48 model just now. The kit will be issued by Dragon, who no doubt will cast many thousands of copies.

But their kit will be of the A1, which were numerous, rather than the M 48 "no letter" which was relatively rare. I want a 48 nothing, so I have looked online and found the conversion parts I will need, which are probably made to order or in small shelf stock.