How to do Aluminum anodizing

A. Hi Rohit.

There are many types of anodizing for many purposes, and many methods, but electrical power is applied to the part, usually while immersed in sulfuric acid, to impart a hard aluminum oxide finish. Nearly any shade of dye is available except white. But not much real progress can be made until you describe the parts; for example, the chromic acid anodizing of aircraft parts is very different from the hardcoat anodizing of wear surfaces, which is very different from the bronze colored anodizing of architectural extrusions. Good luck.

A. For plant design, equipment, materials of construction, solution heating & cooling, etc., see Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon] . A plant with manual operations will differ from one with automated parts transfer in both initial & operating expense.

Use the 'Capital Equip.' link below to find vendors of rectifiers (power supplies), tanks, etc. Note that a hard anodizing rectifier must be capable of higher output voltage, 100 VDC, vs. 25 VDC for conventional anodizing.

US Specialty Color has a dye Color Chart and under Product Information, anodizing pretreatment chemicals, dyes and sealants.

Robert Probert's book, "ALUMINUM HOW-TO -- The Chromating - Anodizing - Hardcoating Handbook" details the anodizing procedures.
S. Kawai's book, Anodizing and Coloring of Aluminum Alloys [affil link on Amazon], ISBN 090447724X, describes electrolytic ("two step") dyeing quite well. This is rather a specialty process for architectural aluminum and cookware in the USA, but seems more generally used in Japan.

Probably, you must establish a record for high quality anodizing over many years before chromic acid anodizing of aircraft parts is a consideration.

Before investing any money, be sure environmental permits can be obtained.

A. Hi Sunil.

This would be sulfuric acid anodizing, with the coloration applied by what is called a two-step process rather than an organic dye. Metal salts are electrically deposited into the anodized pores before sealing, making the color very lightfast.

Regards,