“ …..it's the only varnish left on the market that is real varnish. Others are actualy poly's in disguise”
I hate to be the naysayer, but this statement is not exactly true.
Varnish is basically oil mixed or cooked with resin with a drier added in for curing. The oil can either be linseed or tung. Traditional resin was usually fossilized sap from pine trees. I am not aware of any varnish on the market today that uses pine sap as the resin. Maybe it’s out there somewhere but I doubt it.
Today all varnishes are commonly made from synthetic resins; either phenolic, alkyd, polyurethane, or a combination of phenolic and alkyd is used.
What makes varnishes different from each other is the type of oil and resin that is cooked together. The amount of oil used makes a difference too. For example, what makes a varnish a spar varnish is a high percentage of oil in the mixture. This keeps the varnish soft. Today UV protectors are a factor but traditionally they were not.
There are some very high quality marine/spar varnishes on the market today that are favored by wooden boat builders and readily available. These would include Epifanes, Interlux, and Petit’s Z-spar. These are about as traditional as it gets today and they are not polyurethanes.