Dichromate to water ratio for black finish

Hi Darren. I don't know what metal you are trying to blacken with dichromate and for what purpose or to what spec. But whatever metal it is, it's unlikely that applying carcinogenic hexavalent chromium is the best solution anymore, with the world working hard to get rid of dichromate :-)

Please give us some more details and hopefully we can help.

In my mind, weapons require a higher level of control than most parts. I see that you are at dear old Camp Carroll, so you will have to comply with MIL-Spec's for anything that you do. This includes the qualification and certifications for any of the chemicals that you use, as well as the generic process.

Hello again, Darren. I'm still left with the problem of suggesting "a better safer way" when you haven't told us what metal you are trying to blacken and for what purposes, or to what spec. Dichromate was formerly used for a number of different purposes, although I'm not familiar with dichromate and water being used to blacken anything. You know what you have in mind, but so far I'm afraid I don't. Thanks!