FREE BOOKS

Author's List




PREV.   NEXT  
|<   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31   32   33  
34   35   36   37   38   39   40   41   42   43   44   45   46   47   48   49   >>  
n a ground of leaf gold. Any of them may be used with good seed-lac varnish, for reasons already given. Equal parts by weight of rosin, precipitated rosinate of copper, and coal-tar solvent naphtha will give a varnish which, when suitably thinned and the coats stoved at a heat below 212 deg. F., will give a green japan second to none as a finishing coat as regards purity of tone at least. To harden it and render it more elastic half of the rosin might be replaced by equal weights of a copal soluble in solvent naphtha and boiled linseed oil, so that the mixture would stand thus: rosinate of copper 1 lb., rosin 1/2 lb., boiled oil 1/4 lb., hard resin (copal) 1/4 lb., solvent naphtha 1 lb. When heated to a high temperature this rosinate of copper varnish yields a magnificent ruby bronze coloration, especially on glass. Verdigris dissolves in turpentine, and successful attempts might be made to make a green japan varnish from it on the lines indicated for rosinate of copper. ORANGE-COLOURED GROUNDS. Orange-coloured grounds may be formed by mixing vermilion or red lead with King's yellow, or orange lake or red orpiment (? realgar) will make a brighter orange ground than can be produced by any mixture. PURPLE GROUNDS. Purple grounds may be produced by the admixture of lake or vermilion with Prussian blue. They may be treated as the other coloured grounds as regards the varnish vehicle. BLACK GROUNDS. Black grounds may be formed either from lamp black or ivory black, but ivory black is preferable to lamp black, and possibly carbon black or gas black to either. These may be always applied with the shellac varnish as a vehicle, and their upper or polishing coats may consist of common seed-lac varnish. But the best quality of ivory black ground in the best super black japan yields, after suitable stoving, a very excellent black indeed, the purity of tone of which may be improved by adding a little blue in the grinding. COMMON BLACK JAPAN GROUNDS ON METAL. Common black japan grounds on metal by means of heat are procured in the following manner: The surface to be japanned must be coated over with drying oil, and when it is moderately dry must be put into a stove of such heat as will change the oil black without burning it. The stove should not be too hot when the oil is put into it nor the heat increased too fast, either which error would make it blister, but the slower the heat is increased and the longe
PREV.   NEXT  
|<   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31   32   33  
34   35   36   37   38   39   40   41   42   43   44   45   46   47   48   49   >>  



Top keywords:
varnish
 

grounds

 

rosinate

 

GROUNDS

 

copper

 

naphtha

 
solvent
 
ground
 
mixture
 

orange


boiled

 

vehicle

 

produced

 
yields
 

formed

 

coloured

 

purity

 

vermilion

 

increased

 

carbon


possibly

 

preferable

 

slower

 

shellac

 
admixture
 

applied

 

Prussian

 

blister

 
change
 

burning


treated

 

consist

 
surface
 

COMMON

 
japanned
 

grinding

 

Purple

 

procured

 
manner
 

Common


adding
 
coated
 

quality

 

polishing

 

common

 

suitable

 
stoving
 

improved

 

drying

 

moderately