In further reading your post above. You may have to remove the existing rubber backing. The silicone will replace this for a weather tight seal
Cure time may take 24 to 48 hours
http://www.caulkyourhome.com/frequen...ons.php#prod_6
I've used it on metal plastic glass and ceramic.
IF you are looking for a 5 minute fix. Get yourself some devcon 5 minute epoxy.
And Mix it up. However, It will harden fast and your working time is restricted.
It will also yellow and become fragile the longer it is exposed to UV light.
Life expectancy in this application will only maybe be a year or two at best and will not look good once it yellows.
http://www.devcon.com/prodfiles/pdfs/fam_tds_175.pdf