Glazed back of enamel
Posted: Tue Mar 02, 2021 7:43 am
Hi,
This is Russian silver and enamel badge for graduation of the Imperial University faculties.
The cross is enameled (blue translucent enamel).
C clasp was repaired (replaced). Most likely hard soldered. The mystery is brown vitreous glazing on the back of the cross; it is not original because I have this badge without this feature. Normally, blue enamel would be damaged when exposed to high temperature, but it remained intact.
Therefore, back glazing has something to do with repair and soldering at high temperature, but I have never seen anything like this.
Antique enamel was sometimes done with glazed back because of non matching coefficients of thermal expansion of enamel and substrate (metal).
Jewelers use thermal resistant paste for partial covering of an object when hard soldering, but it is cleaned afterwards, unlike this brown glaze here.
Any ideas are appreciated.
Regards
This is Russian silver and enamel badge for graduation of the Imperial University faculties.
The cross is enameled (blue translucent enamel).
C clasp was repaired (replaced). Most likely hard soldered. The mystery is brown vitreous glazing on the back of the cross; it is not original because I have this badge without this feature. Normally, blue enamel would be damaged when exposed to high temperature, but it remained intact.
Therefore, back glazing has something to do with repair and soldering at high temperature, but I have never seen anything like this.
Antique enamel was sometimes done with glazed back because of non matching coefficients of thermal expansion of enamel and substrate (metal).
Jewelers use thermal resistant paste for partial covering of an object when hard soldering, but it is cleaned afterwards, unlike this brown glaze here.
Any ideas are appreciated.
Regards