Replies

1. 
   Paul_Snyder | Sep 17, 2002 03:45am | #1

   The two have some similar characteristics, but they're not the same.

   Here's a link to the basics on different finishes -

   Wood Finishes

   You can learn a lot about shellac at shellac.net.

   Bob Flexner's book, "Understanding Wood Finishing" has a detailed discussion of the various finishes.

   Paul

   F'burg, VA

   
   

   ---

   Edited 9/16/2002 9:25:06 PM ET by Paul

2. 
   RW | Sep 17, 2002 03:58am | #2

   Get ready for the flood. No, they aren't the same.  Shellac is derived from (feel free to correct me if I get any of this off) - - the lac beetle, which I believe is indigenous to India. Things live in trees and secrete an ooze which you could think of as sap if it helps. That secretion is harvested literally by putting tarps under the trees and whacking them good. This unrefined stuff is the start of shellac, which comes in multiple grades of clarity and refinement (refined by man). The lower or less refined grades often contain small bits and particles of bug. You can buy shellac flakes from a variety of suppliers. You'll find the small bits and pieces in the darker colored flakes. You can progress to Orange and Amber tones, and up to blonde, which is pretty well as refined as it gets. At the top of ths spectrum is super blonde de-waxed which has all or almost all of the wax removed from it and is often used as a sealer / tie coat between disparate finishes. Shellac has been around for ages. It's the hide glue of finishing. It has a reputation for longevity and durability, though it's athletes foor - water, makes it less popular today with your average household furnishings. When you hear the term "french polish" you're hearing about a method of applying shellac. Shellac dissovles in denatured alcohol.

   Lacquer is more recent - early 1900's I believe. Started out with your basic nitrocellulose lacquer which is still popular today. There's nitrocellulose in the content and if I recall correctly this has to do with cotton fibres but I don't recall more than that. The process of making it uses various resins, mastics, plasticizers (which give some flexibility to an otherwise brittle film) and acids - nitric & sulfuric. Lacquer is considered to be somewhat toxic. You aren't going to die if you get a whiff of it, but stand in a shop all day spraying it without a mask and you'll probably regret it. That being said, some people are more sensitive than others. I've seen guys who refuse masks and guys who get a little leak in theirs and throw up ten minutes later.

   There's other forms of lacquer as well, CAB ( cellulose acetate butyrate), CAB-acrylics, and on and on. Your standard nitro is an evaporative finish. When you move up to catalyzed lacquers, pre-cats, and (very similarly) conversion varnish, you have a reactive finish which forms its bond through chemical reaction rather than evaporation.

   Long story short - shellac has been around for ages and originates with bugs. Lacquer is man made and originated somewhere around the end of WWI. Shellac you can swim in, lacquer, not so much.

1. 
   DWRead | Sep 17, 2002 05:55am | #3

   Is the lacquer used on wood the same as the stuff used in Japan and China to make lacquerware?

   In China the first umbrellas were made of paper that was oiled to repel water. According to the article on finishes, tung oil dries and hardens (unlike cooking oils, which get sticky). Was tung oil used to waterproof paper?

   The point of all these questions: There's a company in Boston(www.blanchefield.com) that has been making custom lampshades for almost a century. Most of the lampshades are fabric, but some are paper that is coated with oils and resins so more light will pass through. I was wondering what commercial products could be used to make paper translucent but not leave it sticky or oily.