Blackening stainless steel

[Tovin]

I have a bunch of screws, nuts, and washers that I would like to make dark/black.

I saw a technique where you first clean them in acetone, then let them sit in phosphoric acid, and finally clean them in distilled water. The result would make them dark/black.

Has anyone tried this? Does it work?

Before and after pictures from YouTube:



Source: YouTube
https://share.google/s6eSgcrXDdiJbrkDe

 

[Intet]

Heat them up and dip them in linseed oil.

 

[Thomas_Blekinge]

Instead of phosphoric acid, CocaCola, which contains phosphoric acid, will probably also work.

 

[JohnyS]

I have used bluing solution on regular steel with decent results. I haven't tried it on stainless steel.

 

[Tovin]

Heat them up and dip them in linseed oil.

Is it a better method than the one described above? What shade will they get after such treatment?

 

[Roger Ravnestam]

Unfortunately, you cannot get stainless black with phosphoric acid.

 

[Tovin]

Unfortunately, you can't make stainless steel black with phosphoric acid.

They are screws on a motorcycle, so I assume they are stainless steel 🤔
Is linolja what I should use then?

 

[Roger Ravnestam]

https://provexa.com/process/svartoxidering/