Silicone oil is about your only choice. You can try Glycerine which boils at 290C but MAKE SURE it cannot boil over or get into a flame or hot plate. http://www.uiowa.edu/~chemsafe/MSDS/Glcerol.htm acrolein is carcinogenic afaik Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist