...Pretty grainy and bumpy. It feels like the whole thing is coated in a really fine sand that doesn't fall off anywhere. It's also not scratchy like sand, I just can't think of a better analogy...
Polished vs. Non-Polished
I didn't notice any difference at all... If I had the option to pick between the two (which is only an option for the white) I'd get the unpolished and save myself an extra $1 and a day or two of production time.
Grant it, I've never had a model with a large, flat surface on it... It might be that the polishing process works better for models like that, but for something small and detailed it's not really worth in my opinion. The ceramic pellets they use in the polishing process just can't get into small areas.
All the colors come out really nicely and are super vibrant.
They also look very different from eachother, which is kind of hard to get across in pictures, but the red, orange and pink all look very different. Pink and red are the closest in color.
I haven't tested what happens if one were to soak colored prints in alcohol, water, etc.
If you were cheap, you could totally print your model in white and paint it with acrylic.
If there are a lot of little cracks and crevices (see the dice on right) or the model is fragile it's probably best to shell out the extra $1 and just print it in color.
It's also conceivible that the models could be dyed with alcohol ink (more on that below).
Depends on the print..
As with the rings (right) the detail showed up much better on steel for whatever reason... This confused the bananas out of me because the strong & flexible is supposed to have better resolution, so I'm not really sure why that's the case, but I have found that to be consistently true.
I have a set of plastic dice (the ones that I keep plastering everywhere on this page) that I've carried around with me and they've held up to handling that was between throwing them in the bottom of a backpack then dumping books on them and bubble wrapping each dice individually and carrying them in a special box. Most of the time, I'd just put them in a sturdy zip block with a bit of air and jab them into a backpack pocket I'd filled with other assorted crap and they were totally fine.
Where I get a bit leary of breakage is thin rings...
The stainless ring pictured is thick enough that you'd be totally fine printing this in plastic. It's actually thick enough it's kind of hard to flex.
The polished nickle ring would be fine if it weren't for the little squiggles. While they work in steel/metal, if you were to take a toothpick/similar and poke at them in a plastic print, they'd probably break.
The ring in the white strong & flexible has a number of issues. First and for most, the areas in the webbed part are fragile and arrived slightly cracked because they just weren't thick enough. The second issue is that the band itself is pretty thin and will bend/flex if you squish it between your fingers. If the band were solid all the way around, I wouldn't be too concerned, but the webbing coupled with the thinner ring make this pretty unstable as a design if you print it in the strong & flexible.
This stuff takes acrylic really well. It goes on really nicely and doesn't seem to flake off. It also doesn't bleed, which always makes me happy.
DYING WITH ALCOHOL INK
The ink holds and doesn't bleed anywhere.
VERY hard to control due to the porous nature of the material - the ink is absorbed rapidly and creeps over the surface obnoxiously fast. You also can't really get the ink out once it's on, even if you soak it in alcohol... It's also extremely difficult to control the spread and saturation of the color during the dying.
Reaction to being soaked in Alcohol
If you leave it sit for a while (I'm talking 30+ minutes), it seems to start dissolving slightly. Though it could have just been my imagination... You can sort of see a hole in the right eye of the creepy dude eating an apple that wasn't there when I got the print...
There's really no point... I barely noticed anything happening...
On the bright side, it didn't mess up the texture of the material like sanding steel sometimes does, but it also doesn't seem to accomplish much if anything...