by Bill » Mon Oct 26, 2015 11:20 pm
Not sure I completely understand the question but I am going to give it go anyway. Regarding silvered teak. If you varnish over it without cleaning I believe you will get an inferior product due to the salt and crude that accumulates. A rinse and a SOFT scrub will do wonders if you let it dry first. You could use a teak brightener but seems a pitty sometimes to put chemicals on the wood but sometime you have to do it.
Regardless of what you do if you varnish you will not have silver anymore, it will darken. It the teak was clean the varnish will stay, if it was contaminated it will fail earlier than you expect. If you are looking for it to last longer try a layer of CPES epoxy as a base coat first. The CPES will have instructions but as I recall you can varnish within 24 hours. The varnish will attach and last longer, the color will be deeper as well. We use Bristol Finish on our boat with excellent results, but it is not a true varnish.
without coloring your teak Silver, I can't imagine any way to keep it that color other than no varnish and a salt water rinse weekly or so. Many will claim that that is best anyway.