[3dem] carbon rods for evaporation

[Kelly Dryden]

Hi all,

Since Edwards no longer makes them, we have a Ladd carbon evaporator.  
However, we are having trouble getting the carbon to vaporize.  The rods 
a slightly thinner than we used previously with an Edwards, and vacuum 
reaches about 2E-6.  The problem is that I can only get a very thin 
layer of carbon after 12-15 times of increasing the current nearly to 
the maximum.  I can't leave it on for too long each time because either 
the rod will blow, or the apparatus gets so hot the plastic film is 
damaged.  All the carbon rods we have tried (the originals from Ladd, 
and from Ted Pella and EMS) appear to be graphite.  I've been unable to 
determine if this has always been true, or if it is creating the problem.

Any suggestions for helping us get fine-grained carbon coating for our 
grids will be welcome.

Thanks,
Kelly


*********************************************************
Kelly A. Dryden, Ph.D.
Assistant Professor of Research

Dept. of Molecular Physiology & Biological Physics
School of Medicine, University of Virginia
Snyder Bldg., Rm. 232
480 Ray C. Hunt Dr.
Charlottesville, VA  22908-0886

office: (434)982-0525  fax: (434)243-8271
email: kdryden at virginia.edu