Trepanning is a method of producing large deep holes economically from solid. The process can also be used for boring tubing where heavy stock removal is needed.
A specially designed hollow tool cuts a narrow circular path in the work piece and leaves a solid core. Because all the material is not being removed, the rate of penetration by trepanning is much faster than other methods. Trepanning can produce I.D.s to 24" in diameter, lengths to 60 feet and walls to any desired thickness.
An electrolytic process for producing controlled aluminum oxide films on aluminum that offers high corrosion resistance, increased durability, and is resistance to stains and scratches. It also is a good insulator and nonconductive along with adding a decorative appearance.