I have been trying to find solid silicone rubber (or other) cord suitable for use on a homebuilt vacuum table, but without much luck. It looks like 3/16" dia. would be about right. Searched this site and found little specific information on what people are using and where they buy it. Any help is appreciated.

Back in the day we used 1/4" surgical tubing

Try http://www.allstaradhesives.com/

mcmaster carr has 1/4 edpm foam rubber cord that works great.