[Mike Baker]

I am trying to make my own black concrete acid stain. I am not a chemist other than owning a Chemcraft chemistry set when I was 10 years old.

On a SDS sheet for commercial stain it said hydrochloric acid, sodium dichromate, manganese choride and water.

I bought some "Sodium Dichromate Dihydrate 99.5%" which is red orange, Manganese (II) Chloride Anhydrous, 98+% which is pink.

I mixed 30ML of each into 1000 ml of tap water and 60 ml muratic acid 20° Baumé Hydrochloric Acid 31.5% By Weight. I was expecting black but it was deep yellow.

Can anyone help? I have 6,000 sq ft to stain and commercial stain would cost around $1000.

Mike Baker

As1dSt@yn

[chenbeier]

I would not use it, because dichromate is poisson and carcinogen. Don't polute the envirement.
The mixture would be yellow to green, depending on HCl content. There is nothing what turn it black.

[Mike Baker]

I am going by this information:

https://directcolors.com/datasheets/dc-concrete-acid-stain-sds.pdf

See the formula for black.

Mike

[chenbeier]

Your mixture doesn't fit to the datasheet.

[Mike Baker]

I realize the quantities are off but I stopped when it did not turn black.