There are different types of "silicone" caulks and we found one type
(silicone/latex, paintable) to be much superior to the others. The "pure
silicone", clear bathroom caulk which smells like acetic acid would tend to
peal away from the plastic as it dried. Also, it was very important to
thoroughly clean the plastic tubing/cap before "glopping-on" the caulk.
Another plus: the paintable caulk is available in different colors allowing
one to indulge one's artistic side. ;)
__________________________________________
Jack Presley voice: (530) 752-7327
Protein Structure Lab fax: (530) 752-8969
UC Davis http://psl.ucdavis.edu