Dauvit-- I have nitric acid that is 74% (as stated by the Lab).

What ratio to water would I used to dilute it for etching silver

or copper? It’s been a LONG time since I did any etching. .Del

It depends on what you are wanting to do. A good bet is to mix it

to between 12 and 15% for a slow and accurate etch with minimal

underbite, but you can mix it up to 25% for a faster, less accurate

etch.

To calculate the desired strength, work out the volume you need to

produce (say 100ml) and the strength you require (say 12ml): in

this 100ml, there needs to be 12% pure acid, or 12ml. How much 74%

acid gives 12ml of pure acid? Divide 12 by 0.74 and you get 16.21.

OK. Therefore you need to use 16.21ml of 74% acid in (100-16.21)

83.79ml of water to create 12% acid.

Sorry if this seems very complicated: I know how to do it, but

can’t work it out as a formula (maths was never one of my

strengths). The above works if you substitute the figures you

actually need, for example 250 ml of 18% acid.

All the best,

Yours aye,

Dauvit Alexander