Rosin is an ingredient in printing inks, varnishes, adhesives (glues), soap, paper sizing, soda, soldering fluxes, and sealing wax.

Rosin can be used as a glazing agent in medicines and chewing gum. It is denoted by E number E915. A related glycerol ester (E445) can be used as an emulsifier in soft drinks. In pharmaceuticals, rosin forms an ingredient in several plasters and ointments.

In industry, rosin is the precursor to the flux used in soldering. The lead-tin solder commonly used in electronics has about 1% rosin as a flux core helping the molten metal flow and making a better connection by reducing the refractory solid oxide layer formed at the surface back to metal. It’s frequently seen as the burnt or clear residue around new soldering.

A mixture of pitch and rosin is used to make a surface against which glass is polished when making optical components such as lenses.

Rosin is added in small quantities to traditional linseed oil/sand gap fillers, used in building work.

When mixed with waxes and oils, rosin is the main ingredient of mystic smoke, a gum which, when rubbed and suddenly stretched, appears to produce puffs of smoke from the finger tips.

Rosin is extensively used for its friction-increasing capacity in several fields:

• Bowed string players rub cakes or blocks of rosin on their bow hair so it can grip the strings and make them speak. Extra substances such as beeswax, gold, silver, tin, or meteoric iron are sometimes added to the rosin to modify its stiction/friction properties, and (disputably) the tone it produces.
• Powdered rosin is often applied to new hair, for example with a felt pad or cloth, to reduce the time taken in getting sufficient rosin onto the hair.
• Violin rosin can be applied to bridges in other musical instruments, such as the Banjo and Banjolele, in order to stop the bridge moving during vigorous playing.
• Ballet and flamenco dancers sometimes rub their shoes in powdered rosin to reduce slippage before going on stage – it was at one time used in the same way in fencing and is still used as such by boxers.
• Gymnasts use it to improve grip.
• Applied onto the starting line of drag racing courses used to improve traction.
• Bull riders rub rosin on their rope and glove for additional grip.
• Baseball pitchers and ten-pin bowlers may have a small bag of powdered rosin nearby, to use on their throwing hand, for better control of the ball.

List of Rosin Uses

Hot-melt and pressure-sensitive adhesives; mastics and sealants; varnishes; ester gum; soldering compounds; core oils; insulating compounds; soaps; paper sizing; printing inks; violin Rosin; synthetic resin; rubber; tackifiers and sealants; coatings and lacquers; healing salves;