A sine qua non is that the glass be hot enough to melt the shellac.
The cement consists of a mixture of shellac and 10 per cent of oil of cassia.
It is then coated with shellac by heating and rubbing upon the shellac.
On no account must the shellac be allowed to get overheated.
Shellac is the most common and the most useful of the spirit varnishes.
In the process just ...