Dec 072016
 

When it comes to finishing stocks for antique guns I like to use the traditional materials – partly for authenticity and because they are pleasant to work with, although undoubtedly not as durable as a thick coat of polyurethane varnish!   Guns were finished using one of two methods, oil finishes or spirit varnishes.  Oil finishes basically use mixtures of oils (usually boiled linseed oil) and waxes ( beeswax and other hard natural waxes) and harden by the oxidation of the oils by oxygen in the air, which takes place fairly slowly – driers, typically based on manganese compounds, are used in low concentrations to speed up the oxidation. The alternative traditional finish was spirit varnish, using a solvent – typically alcohol, in which a naturally occurring material that is transparent and hard is dissolved – typically shellac (secreted by an insect) or occasionally copal varnish (from the resin of a tree), or other resinous material – alcohol and Shellac are the ingredients of traditional French Polish and were very widely used before modern synthetic materials displaced them.   Spirit varnish hardens by evaporation of the spirit  to leave a thin coating of the varnish – the alcohol evaporates rapidly so the varnish hardens quite quickly and far fewer coats are needed compared to oil finishes, but its more difficult to get an even finish. Shellac varnish itself has a brown tint, and so does darken the wood slightly – the better the quality of the shellac the lighter the colour.    It is also possible to use both materials on the same job.

 

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