Uploaded June 2025 | Updated September 2026, 1 week ago
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
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
