More often than I expected I’ve talked to people who were surprised to hear how abysmal original casts can be. Because, when someone more familiar with “western” model kits hears “original vs. recast” they may think of a high quality/expensive product vs a cheap remake. In my experience, the quality of original casts have a huge range; while Chinese recasts have a narrow range. But, recasts can never perfectly recreate the original cast since shrinkage always occurs.
Why is there a wide range of quality?
Originally garage kits were cast by hobbyists in their home or garage (hence the name “garage” kit)”. Recently more circles (groups that make fan-works) after sculpting the master copy have their kits cast by professionals, but there is still a large amount of circles that do the bare minimum or have to rush to be ready for an event.
Photo from @GRIZZRYPANDA 
Photo courtesy of Plum Workshop
GrizzryPanda‘s kits (left) are professionally cast, trimmed of flash, and packed into blister packs. Meanwhile, Atelier Hiro (right) packs their kits into regular plastic bags straight from the molds. Both of these circles have been making garage kits for over 10 years.
Common Issues:
1: Bubbles
Polyurethane resin is made by mixing 2 chemical mixtures. The stirring process can introduce bubbles and without proper air vents in the mold or using a pressure pot there will be tiny bubbles in the final cast. Bubbles need to be drilled out and filled with putty before painting.
2: Excessive Flash & Large Tabs
“Flash” is the general term for extra, unwanted resin. Multiple channels are needed in silicone molds to make sure resin completely fills it. “Tabs” are where the channels meet the kit itself and with good planning they can be placed in smart areas. But, sometimes very large tabs can be placed in poor areas where removing them damages the kit.
Most circles will cut away the flash, but still leave the “tabs” (small areas where the channels meet the sculpt) as to not damage the kit itself. Large tabs can also be a problem, but large amounts of flash cover a lot more surface area around delicate areas.
Photo courtesy of Emerald Angel Studio 
Photo courtesy of Plum Workshop 
3: Sparse Resin
Resin doesn’t always fill the mold completely or it’s very thin to the point of being see-through. This usually happens with large thin pieces like dresses. The gaps should be reinforced or filled with putty.
Photo courtesy of Emerald Angel Studio 
Photo courtesy of Plum Workshop 
Why don’t recasts have these problems?
The two recasting companies reccomend: GK-Model and E2046 (I vastly prefer GK-M) will have to prepare and fix issues like these before they can make their own recasts. The master kit needs to be free from defects before they can make copies. Because there is competition, there is incentive to provide high quality recasts (there was a time E2046 didn’t have much competition and there were some common QC issues). The reasons I prefer GK-M is because overall they have higher quality casts.
But, because they are using copies of the original master and making copes from that there will be some shrinkage. Frenchdoll from the circle Cerberus Project makes sure their original kits fit perfectly in difficult areas so that recasts are more difficult to assemble.
At the end of the day,
If only one circle is making a kit of my favorite character I’ll suck it up and deal with issues like these. Sculpting is hard and making great quality kits is difficult and expensive. I prefer to directly support Japanese sculptors even if there is a chance the kit will be a nightmare. On the other hand, after all my years I now have a list of circles whose work and quality I adore and I will go out of my way to buy from them directly. So, good quality can build loyalty.