I've had Instant Mold laying around for a while and I haven't done much with it. I decided that I needed to give the product my full attention, instead of trying to use it in a hurry because I'm working on something else.
From my Dark Angels Veterans kit I attempted to cast the terminator legs, several heads, the meltagun, flamer, and some icons. I didn't notice any errors in the mold so I stuffed greenstuff in an effort to get the most detail.
The little detail in the front of the heads and legs, as well as the tiny bits on the guns didn't turn out very well at all, yet the simpler icon bits turned out great. I'm not an expert at green stuff, I may have been using too much yellow as the loss of detail seemed to be due to shrinking.
Instant Mold: Soon to be replacing Finecast in stores near you.
With the icons I only cast the front because they'll soon be attached to the front of my Watchers in the Dark.
With this I attempted to cast one directly onto the Watcher's shield, while most of them were just cast individually. Although the cast is secure to the shield, there is flashing to be removed so in the future I won't be casting a mold directly to the model.
So if nothing else, Instant Mold is great for getting a bunch of decorative pieces to spice up your army. I may have been using the wrong blue/yellow mixture, although I've heard similar things elsewhere. I don't think Instant Mold will save me from actually buying models, but it will allow me to use some of the smaller pieces that only appear once on the sprue. I'm a fan, I probably just need more practice.
The clear nature of the mold allows you to see air bubbles.
It will eventually pay for itself (~$11), depending on your skill and frequency of use.
Highly detailed pieces can't be cast with greenstuff.
It's easy to misalign and miscast, wasting greenstuff.
It's very difficult to cut open the mold without cutting the model in tight areas, such as in between legs.
As for my Watchers, they're progressing nicely. I have all eight's hoods done, I will need to file away some of the sloppier areas though. I want to add more detail to the models but I'm not really sure how to go about that since they're so small. Another problem that I've run into is the hand sizes. My test model used a human hand, while the goblin hand is much larger. Currently, all but one of my goblins have goblin hands with weapons crudely attached. I need to visit the bits bit and either attach all human or all goblin hands, I hate being inconsistent. The human hands are more appropriate for real Watchers, while the goblin hands are more daemonic. I need to figure out where I'm going with this army.