In Vol. 334 "Applications of Thermal Spraying", we introduced examples of thermal spraying adopted in various industrial fields. In this lecture, we will review the application examples of thermal spraying used in fine arts and crafts.

(1) Application to wood

Thermal spraying can be easily applied over wooden materials, such as woodcarvings and wooden signboards.Wood having rough surfaces or that is known to leak oil when being exposed to heat is not suitable for thermal spraying. However, using wood containing little oil and include the surface polishing process, they can be compatible with thermal spraying.The procedure is explained below.
First, apply zinc as undercoat for about 100 µm thick using wire flame spraying.Be careful not to burn the wood during this time.Next, spray the wood using metal as a top coat that will produce a desired color phase, such as aluminum bronze or brass, and deposit it for about 3 mm thick. Use a grinder, buffing, wire brushes, or apply chemical treatment as sulfidizing, to create metallic arts.They are absolutely creative and durable.

(2) Application to sculptures such as relief

Reliefs and shaped articles made of plaster or plastics can be easily transformed into metallic articles using thermal spraying.
To apply thermal spraying to a relief made of plaster, fill the bubbles on the surface first, and then apply a finely textured film made of aluminum or compatible materials for about 150 µm thick, using arc spraying.For plastics, use arc spraying to form a copper film first, followed by chemical treatment such as etching to produce polished look on the surface.

(3) Repairing casted statues

Statues are created by casting metals. However, even small flaws in casting will usually make the workpiece a defective item.Thermal spraying is one of the techniques used for repairing such flaws.
Casting flaws vary, but for build-up layers, the backside can be repaired by thermal spraying. Holes and areas that were not soaked in hot water can be repaired from the back using plaster or plastics, and by spraying metal for about 5 mm thick from the front. Post-processing is adopted for giving a special touch.

(4) Copying by thermal spraying

Zinc spraying is a technique used for copying the surface of an original model faithfully.The thermal spraying film capturing the original model is usually as thick as 5mm. The surface is extremely smooth and glossy.Since the spraying material for the second layer can be selected freely, it can be customized for intended purposes.
Using a relief made of plaster as the original model, metal reliefs having the same pattern can be replicated by wire flame spraying and arc spraying.Any material can be used for the original model as long as the heat conductivity is low.