[Rockhounds] (was)cinnabar lacquerware (now) Lacquer

[Ted Kowalski]

Uh, no..., yes, well in one way at least. 

I'll post a few pieces of information on some common coatings and maybe
confuse the situation a little more.

Shellac is an animal product, a resin secreted from the Coccus lacca (lac
beetle), a scale that feeds on certain trees in India and southern Asia.
Preferred solvent is alcohol (ethyl of course). Relatively unrefined shellac
is reddish amber (called garnet) in color, 

The lacquer in common use in America and Europe is actually nitrocellulose
(cellulose nitrate) dissolved in various solvents; methanol, acetone, M.E.K
and others.

Japan or oriental lacquer is sap is collected from Japanese urushi trees
(the lac tree). Only a cup of urushi sap is collected from a tree in a year.
As such true oriental lacquer is much less common and much more expensive.
Preferred solvents are water and turpentine. 

Two links:
http://wwwsoc.nii.ac.jp/jsac/analsci/ICAS2001/pdfs/0100/0155_4e04n.pdf

http://books.google.com/books?id=YtePXGmDI70C&pg=PA352&lpg=PA352&dq=lac+urus
hi&source=web&ots=V5Z2tTtx5l&sig=wd62oVj2vnbTTAQZK17KczUlVMU#PPA352,M1
(watch out for the multiple lines, cut and paste the whole thing)

In the second link, the description of how cinnabar (there! the rock stuff
to keep this on topic), is rubbed into the oriental lacquer to obtain the
desired shade of red. 

The first link is a rather technical description including how oriental
lacquer cures by polymerization and how the cured lacquer is subsequently
insoluble. Offhand, I would expect the cinnabar that is held in suspension
by the polymerized lacquer to be safe for general handling. That is, don't
destructively heat it or gnaw on it and you shouldn't need to worry about
mercury contamination. Think of it as sealing the cinnabar in epoxy. If the
cinnabar lacquer ware has a final clear topcoat of lacquer (likely) you
shouldn't receive any mercury exposure.

Just my opinion... Well, except for the info about shellac and
nitrocellulose lacquers.

Ted Kowalski
Fredericksburg, VA USA




<snip>
http://www.go-star.com/antiquing/lacquerware.htm

Apparently cinnabar lacquerware was originally made with ground 
cinnabar mixed with lacquer, beginning over 2300 years ago, though 
cheap modern varieties contain polymer or other synthetic materials 
instead.  BTW, I didn't know that lacquer came from a tree called the 
lac tree!  <snip>.

Aloha, Kitty
<snip>