Haven't done this for a while, but what we used to do was mix Vaseline plus mineral oil (both purchased for cheap at the local drugstore), and then apply it using a 10 ml syringe with a pipet tip attached.
We used the mixture of Vaseline + mineral oil because Vaseline alone is too viscous (unless you want to develop Popeye forearms). Heat a jar of Vaseline in a hot water bath (NOT OVER A FLAME--it's flammable!) until it melts. Mix in about 10-20% mineral oil by volume (you can play with this ratio until you find the viscosity you like); then draw the mixture up into syringes while still liquid. The procedure a little messy, so fill a lot of syringes at once and you're set for years. Pat On 18 Nov 2011, at 12:55 PM, Dima Klenchin wrote: > Hello, > > I wonder what everyone is using for sealing hanging drop slides on VDX > plates? For the most part, we paraffin oil but I am unhappy with it because > it is too think and too frequently there is break in the oil and the drop > dries too much. I find vacuum grease to be not terribly practical because it > takes too much time - particularly when the well needs to be opened (seeding, > modifying well content, etc). > > In ideal world I would like to find a much thicker oil that 1) contains as > little volatiles as paraffin oil, and 2) allows no more water vapor diffusion > through it than paraffin oil. Hampton suggests Cargille immersion oils for > this purpose but the MSDS for these oils states that they have slight odor, > so I am a bit concerned with unknown volatiles getting into crystallization > drop. > > So, what do you like to use? Thanks much, > > - Dima