Sound Dampening Coatings

Question:

My company makes window balances. One of the parts of this balance is a metal spring. When the spring is compressed and expanded it can make a "boing" sound. The spring is compressed when the window sash is raised and expanded when the sash is lowered. Is there a painting process that can help quiet these springs?

The spring is made of two types of metal: phosphorous coated music wire (ASTM A228 and A228M specifications) and hard drawn galvanized steel wire (ASTM A227 and A227M). J.W.

Answer:

Sound dampening coatings are generally soft and elastomeric and, in the case of a spring coating, it must also be extremely flexible. Nearly 50 years ago, when I was an industrial paint consultant in training (one has to start somewhere), my company applied a plastic cement to the inside of steel electrical equipment cabinet panels to keep them from vibrating and "drumming". The coating acted as a vibration damper. That coating would be too rigid for your application. My first suggestion would be coating the springs with a flexible polyvinyl chloride powder or liquid coating. Another candidate would be an elastomeric polyurethane coating. In either case you will need to apply a primer. Most of the other polymers are too rigid. The springs must be cleaned to remove oily soils before coating.