Could one of you smart guys explain to me the differance between the 2 that makes resin molded items offer so much more detail than injection molded styrene items.I can’t just be better artists making the molds,they could be persuaded by a healthy salary.This question has bugged me since I returned to modeling after a many year hiatus.I don’t like sounding like a dullard when someone asks me similar questions. thanks ahead, rudedog
You’re correct in that the difference lies in the molds. As you have seen, resin allows for very fine cuts, crevices and textures whereas injection plastic tends to have softer detail. The reason is that for injection plastic sprues to be removed, they have to be pushed out of the molds after their molten plastic hardens (note the ejector pin marks). Therefore, very complex parts will need to be made in several components (think AFV Club kits) or compromises will need to be taken. The introduction of the “slide-mold” technology into model making (done with great fanfare by DML) allows the maker to add cuts or holes to parts that otherwise only have details on two surfaces. By sliding a rod sideways into the mold before the plastic is injected, a hollow gun tube can be made. Then, before the sprue is removed from the two part molds, the rod is withdrawn, allowing the gun tube to be ejected from the mold. Get it?
With resin, fairly radical parts can be made because the molds are made of RTV rubber which mimic surface detail of the “master part” extremely well. The master is removed and liquid resin is poured into these molds in a vacuum chamber. When the resin cures, the pieces are manually removed from the molds which are fairly flexible. This allows for undercuts, fine details and a fidelity to the original that is much higher than most styrene parts. After a while, the RTV mold begins to break down and another mold needs to be made. The cost of RTV, resin and the manual labor involved are much more complex than an injection mold which will last for 100,000s of parts before any maintenance is needed.
Another differance is the material used. Resin is about as thin as water when poured where the molten plastic is much thicker (think volcanic lava) so the resin is more able to flow into tiny crevaces.
T-26,That was an excellant synopsis.I truly understand now.And Claymore,thanks also,it makes sense. Semper fi , rudedog