Once you put varnish on your wood parts, it will be very difficult to get anything to stick to it. Removing it is difficult and you must get it all off, even out of the pores, to get a good bond. If you think there will ever be a need to bond to that part, seal it with the same thing you use for your resin.
Mixing your resin mixture with a little acetone makes a very good sealer. See N64KR at http://KRBuilder.org - Then click on the pics? Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il ? MVN Best KR at 2013 - KR Gathering in Mt. Vernon, Il ? MVN Best Interior at 2013 - KR Gathering in Mt. Vernon, Il ? MVN Best Paint at 2013 - KR Gathering in Mt. Vernon, Il ? MVN Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il ? MVN Daniel R. Heath -?Lexington, SC