The cheap magnetic stirrers don't seem to have the gazoots to stir something as viscous as olive oil for days on end. They tend to burn out. One of our guys (hav) fried a bunch of hana stirrers, and eventually got a Benchmark stirrer (about $200). I got one on his recommendation, and it has been reliable. Regarding crushing between glass plates, I don't know. C60 is pretty soft, so it might work, but you might want something convex so that you can concentrate more pressure on a crystal. Some people have crushed it between two spoons. You could probably use a glass plate and the back of a spoon, or maybe a glass rod. Lots of ways would probably work. Personally, I use a porcelain mortar and pestle, though I know that I lose a bit of it. A stainless steel mortar & pestle might lose less, due to less porosity.
There does seem to be uneven quality. I've used a Hanna for a couple of years and haven't had a problem. But I'm only using it for this, cutting the power when not in use, and I use it at less than full speed. The price ranges on either side of a hundred. At Amazon, HI 190M-1 seems the most popular of that brand, with a lowest price of $86. As for crushing, a stainless mortar works very well, as it doesn't absorb the powder like ceramic.
I think grinding prior to mixing in Olive Oil is the single most important factor impacting how much and how quickly the C60 dissolves. I bought the mortar Turnbuckle provided a link to a while back. It works great. The only issue is that the C60 can tend to stick to both. Here's what I do to avoid losing much at all.
Wash hands. Do the grind in mortar. Measure and pour some specific small amount of Olive Oil into the mortar. Stir the Olive Oil/c60 mix in the mortar. The OO mix gets very dark because the C60 is concentrated. Pour that batch into whatever bottle you're using. (I now use dark wine bottles. They work great, especially the ones with a screw cap.) That first pour will get most of the C60 into the bottle. Pour another small amount of Oil into the mortar and repeat process as necessary. I also use use the pestle to stir and that gets C60 off the pestle.
There's always a bit left, but not much... And, well, that last bit is finger licking good. :-)
Edited by HighDesertWizard, 05 April 2015 - 06:21 PM.