albqbrian - 15-4-2012 at 23:37
Check out this baby offered on Ebay. Granted it's expensive.
http://www.ebay.com/itm/Floating-Stir-Bar-Stirring-Teflon-PT...
It is a normal stir bar suspended off the bottom by a thin, plastic, three-legged "cage". What you get is a stir bar that can't hit the bottom or the
sides of the vessel it's in. Pretty cool. It has an "Make an Offer" option; I wonder how low he'd go?
Arthur Dent - 16-4-2012 at 04:50
Cool,
I have used a "ghetto" version of this which consisted in a 1L beaker, the ceramic bottom plate of a dessicator (it has holes), and three ceramic
isolators as standoffs. You put the stirbar in the middle of the beaker and the three standoffs on the sides, then the bottom plate over. I use this
setup to stir the acid when I attempt to dissolve a metal.
You can't use the stirrer at high speed or the standoffs may be displaced, but just the small movement of the acid greatly accelerates the reaction
with the metal and prevents foaming from occuring.
Robert
bahamuth - 16-4-2012 at 06:50
It's a stirbar for cell cultures, and the point of suspending the stirbar is to not grind the cells to mush.
And if you have a magnet that flies and jumps off into the walls you are either doing it wrong or the stirrer plate is crap, the latter being the most
probable reason. The only stirrer apparatus magnet I ever was happy with was a analog Heidolph MR-something, everything else is just crap compared to
those magnets and hot plate.