Replies

1. 
   Paul_Snyder | Jul 25, 2002 12:13am | #1

   Good question! There's a lot of misinformation floating around on the subject of varnish, varnish & oil mixes, and polyurethane (a type of varnish).

   Here's some links to articles on the subject (though for the whole story, get a copy of Bob Flexner's book - "Understanding Wood Finishing."

   http://www.popularwoodworking.com/features/finish5.html

   http://www.taunton.com/finewoodworking/pages/w00060.asp

   http://www.popularwoodworking.com/features/finish2.html

   http://www.woodfinishingsupplies.com/varnish.htm

   http://www.assoc-restorers.com/r-articles/sal/varnish.html

   http://www.assoc-restorers.com/r-articles/sal/bubble.html

   http://www.assoc-restorers.com/r-articles/sal/brshvar.html

   Paul

   F'burg, VA

1. 
   sorethum1 | Jul 25, 2002 01:03am | #2

   Well.  I'm glad I asked.  Thanks Paul.  I'll be back after I've done some reading.  Todd

2. 
   StanleyNiemiec | Jul 26, 2002 12:45am | #3

   I consider a varnish to be those finishes that combines a resin with an oil in an organic solvent.

   The resin can be naturally occuring (copal), natural formulated (soya alkyd), or synthetic (polyurethane or phenolic).  The oil is generally boiled linseed though sometimes a tung oil may be substituted.  The percentage of oil determines if it is a long oil varnish or a short oil varnish.  Long oil varnishes are not as hard and thus more flexible.  The organic solvent is typically mineral spirits or historically, turpentine.

   A lacquer is basically a resin (as with nitrocellulose) and oxigenated solvents like alcohols, toluene, etc.  Shellac (the Brits call it spirit varnish to make a mess of things and to generally confuse the issue) consists of shellac resin and alcohol.

1. 
   Jamie_Buxton | Jul 26, 2002 05:33pm | #4

   So you're saying water-borne finishes can't be varnish?

1. 
   bobhallsr | Jul 28, 2002 07:02am | #5

   If I may offer an opinion:

   <So you're saying water-borne finishes can't be varnish?>

   Not at all. Go back to Stanly's paragraph on varnish components, perform a litle chemical wizardry and emulsify the solids components of the formula, substitute water for the organic solvent (the vilotiles). When the water evaporates, the varnish coalesces and the remaining trace amounts of the organic solvent evaporates. This is, of course, an over simplifiction and I don't believe that this varnish will have an oxidative cure such as the oil based varnishes. But I'd call it varnish.

   BJ

   Gardening, cooking and woodworking in Southern Maryland