ammonium bifuoride

[Jerry Pinsky]

Does anyone have experience using ammonium bifluoride to remove rust stains from concrete? Normal rust removers (oxolic acid) don't seem to work.

Jerry

[RB]

Ammonium bifluoride is an etchant. It will hydrolyze in the presence of water and give you hydrofluoric acid. Although the HF will be somewhat dilute, be cautious. I have had some of my worst acid burns from HF.

Many years ago HF used to be supplied in waxed cardboard containers (before the advent of plastic, Nalgene containers) since it will dissolve glass. Frequently it leaked from these containers. It has low surface tension and penetrates the skin and then starts to burn out from the bone, much like glacial acetic acid. It can ruin an otherwise good day.

I doubt that this will remove the rust stain, it will most likely remove the concrete that has been stained if it does anything beneficial.

Gloves and goggles would be a good investment. As with any acid add it slowly to water, don't add water to it.

RB

Jerry P> Does anyone have experience using ammonium bifluoride to remove rust stains

[Jerry Pinsky]

Thanks. I though I knew what I was dealing with but it has been a long