Anodizing Aluminium - No Sulphuric Acid and Less Than $50 To Do (Sodium Bi-Sulphate)

Anodizing Small Parts without using Sulphuric Acid and with a total cost of less than $50.

This is a guide on how I anodize small aluminium parts to give them an aesthetic anodize, using sodium bi sulphate, in place of sulphuric acid.

This is about as basic as a set up as it can be, and I want to show you that we can still achieve great results on small parts. However there are some constraints to be aware of:
We are not aiming for an exact thickness of oxoide, however if you let the current drop to near zero, it should be thick enough to take up the dye
some dyes will take up better than others. Rit black and other black dyes have a reputation for being more difficult to get good finishes on
sodium bi-sulphate is reportedly a safer acid than sulphuric acid, but 20% bi-sulphate is still a dangerous chemical and should be handed carefully
as the part grows in size and complexity, bubbles may become an issue and will need to be removed though the use of a stir or bubbling method
anodizing coats thinner than 30-40 microns generally do not provide hard wear resistance
This guide is intended for basic aesthetic coats for small parts
Whilst the process is straightforward, it will take a few goes to get right

As a final note, whilst anodizing can be a straightforward method, I only recommend doing it if you feel that it needs to be done, in this case to add colour. I have done many aluminium parts over the years and most of them did not need to be anodized and were left bare, given a coat of etch primer and painted, or given a coat of clear lacquer.

#machining #diy #anodizing