Registration is now open for the new Surface Decoration Techniques seminar scheduled for 7, 8, and 9 March 2023. The course is 15 hours in the afternoon from 14.00 to 19.00.
Surface treatments are procedures aimed at permanently or temporarily changing the appearance of objects and in our case jewelry, then basically metals. The methods for achieving decorative effects are virtually endless, because anyone can modify those already known or invent new ones.
Seminar content.
This seminar covers some of the topics consisting of permanent modifications obtained by superimposition/insertion of one or more metals on another metal-base, or by surface deformation:
– Kumboo (Married metals);
– Nunome zogan (inlay);
– Reticulation (deformation).
KUMBOO
I bring together under the heading «Married Metals «all combinations of different metals and/or alloys, joined together without added welding, but only by the high temperature and pressure exerted between the surfaces.
The simplest example of this type of joining is what is known as KUMBOO, or kumbu, a technique of Korean origin, which will be one of the seminar topics, while the more complex technique is mokume, which will be the subject of a specific seminar.
The Kumboo technique involves the application of pure gold leaf to a silver surface, which can be an already completed object or a part yet to be assembled.
Topics covered during the seminar (live/video demonstration and participant practice).
- Production of gold or silver leaf;
- Preparation of surfaces for leaf application;
- Application of the leaf and subsequent treatments.

NUNOME ZOGAN
To the large family of INLAY (literally «insertion») belong several techniques that sometimes seem totally different from each other.
What distinguishes and fraternizes these different procedures is the fact that they all involve the insertion of leafs/plates and/or wires of one metal (usually-but not only-pure silver and pure gold) on a base of another metal/alloy of greater hardness in which engravings and depressions are made by means of special burils or chisels, and without the use of soldering.
In Japan all the insertion techniques are grouped in a mega-family that goes by the name of ZOGAN. One version we have always used in goldsmithing courses is called NUNOME ZOGAN and consists of creating on an iron plate a useful surface for the insertion of pure gold and/or silver leaf or wire.
Topics covered during the seminar (live/video demonstration and participant practice).
- Production of gold or silver leaf;
- Preparation of the iron base;
- Examples for making rings or bracelets;
- Finishing the objects.

RETICULATION TECHNIQUE
This is a technique of deforming surfaces (mainly silver, but also gold) by means of fire: by appropriately heating a properly prepared surface, it wrinkles, creating strong contrasts.
Topics covered during the seminar (live/video demonstration and participant practice).
- Fabrication of the silver alloy for reticulation;
- Preparation of the plate for reticulation;
- Reticulation process;
- Use of the reticulated plates.
Materials and tools to be provided by participants. - Basic tools (pliers, files, hammer, emery papers, drills, cutters, compass, shears);
- At least 0.5 grams of pure gold, or a few grams of pure silver for making the leaf;
- At least 20 grams of pure silver for making the sheet to be reticulated.

Note: The school can provide a tool kit. Contact the secretary’s office
Materials provided by the school.
In addition to the use of all equipment, the school provides:
- 925 silver plate and wire
- Iron plate