What is the difference between a matte finish and an electropolished finish on vacuum tubing?
A matte finish is a bead blast finish on tubing exterior only. The surface has a uniform dull appearance. Most fittings are constructed with a matte finish. An electropolished finish removes a small portion of the surface of the vacuum tubing, usually both inside and out, which results in a surface that traps less water vapor than an unpolished surface. In most high vacuum and many ultrahigh vacuum applications, a matte finish is acceptable. For ultrahigh vacuum applications requiring a minimum of trapped gases in a chamber’s surface, an electropolished finish is desirable. Additional time and expense accompany electropolishing.
