Trying to understand varnishes

[JHZR2]

Varnish is a term that gets thrown around a lot. Im trying to better understand wood protectants that some people make with solvent (spirits, naphtha, turpentine), oils (BLO or tung oil), and then a "varnish".

I get it that the resin used to make a varnish can be lots of things, including polyurethane.  Its the other options I dont get.  I understand they can be classical (sap-based) resins, alkyd or phenolic chrmicals, etc. 

But here are my questions:

-where does one procure these to make your own blends of "danish" oil (I think that is the generic term) or other such things?  Is there a requirement to buy a finished product (say minwax polyurethane or epifanes varnish) to mix in, or are there other ways?

- if one wants to build on such a finish, shouldnt (can?) a lacquer be ysed since lacquers supposedly "melt" into each previous layer?

- if something like a box store polyurethane was used, woukd the wood be shot ever after, since the pores would be filled with poly?

Anyone care to recommnd their choice for rejuvenating and protecting new and old (75-100yrs) wood, ibside and outdoors?  Im thinking the recipes may differ from application to application.

Thanks!!

 

[leakyroof]

There is some great reading out there from various authors, especially with breaking down historical make-up of varnishes to present day mixtures.
A wiping varnish is often where people will tweak a commercial product to their own liking.
But, Finishes in general can get confusing, muddled and down right false at times with claims and ingredient listing.  Bob Flexner(. Hope I got his name right...) has a great book or two on the subject of finishes and covers Varnishes in depth.https://www.amazon.com/UNDERSTANDING-WOOD-FINISHING-BOB-FLEXNER/dp/B000H6EJ4U
  As far as protecting that wood. Can you elaborate?  Are you looking for a clear finish and not paint on the 'outside' wood?  A Spar Varnish or Marine Varnish would best for outside Varnish protection since it will have UV additives in it.
Interior Varnish will be different.
I use Pratt-Lambert 38 for interior work and Epifanes for Exterior work. Both have been very good for me and predictable.

 

[JHZR2]

Thanks for the reply.  I've done a lot of reading, and even got the book you mentioned from the library once. 

The challenge I have is finding the real "varnish" component... That is, the resin component necessary to make my own.  So many varnishes have gone off the market, or have converted to urethanes, instead of being more natural or at least, less plastic combinations.

There seems to have been a lot more non-urethane options even just a few years ago.  Now, it seems that there is one SW product, the P&L 38, and Epifanes.  Yes, a search will find other options, but I was generally interested in fairly readily available sources from which I could make my own "Danish oil" mixtures to experiment with. 

Even the local P&L dealers don't carry 38, BM doesn't offer anything, SW offers a fast oil varnish, and I can get Epifanes from Amazon... So the only local option is SW, or to buy a poly-based product most anywhere...

Essentially what I'm looking for is an internal and external varnish product that will build upon it self by chemically combining, "melting" etc into the previous layer, unlike polyurethane that can only be sanded for more surface area, and then interlocked into place...

 

[leakyroof]

Thanks for the reply.  I've done a lot of reading, and even got the book you mentioned from the library once. 

The challenge I have is finding the real "varnish" component... That is, the resin component necessary to make my own.  So many varnishes have gone off the market, or have converted to urethanes, instead of being more natural or at least, less plastic combinations.

There seems to have been a lot more non-urethane options even just a few years ago.  Now, it seems that there is one SW product, the P&L 38, and Epifanes.  Yes, a search will find other options, but I was generally interested in fairly readily available sources from which I could make my own "Danish oil" mixtures to experiment with. 

Even the local P&L dealers don't carry 38, BM doesn't offer anything, SW offers a fast oil varnish, and I can get Epifanes from Amazon... So the only local option is SW, or to buy a poly-based product most anywhere...

Essentially what I'm looking for is an internal and external varnish product that will build upon it self by chemically combining, "melting" etc into the previous layer, unlike polyurethane that can only be sanded for more surface area, and then interlocked into place...

. Jamestown Distributors will carry many Varnishes that you could research about. Interior and Exterior for boats.
VOC regulations have taken a toll on where some finishes are sold or prohibited for sale. California I think doesn't allow Epifanes to be sold there.