Homebrew PCBs

On 30/05/16 04:52, AncelB mosaicmerc@... [Homebrew_PCBs] wrote:
> Just as an FYI I use Nitric acid, and have been doing so since 1987.
> Fairly easy to handle at the lowish concentration in the etchant tank. I
> can handle the boards with bare fingers once I get them rinsed inside of
> 10 seconds so I etch next to the rinse tub sink, although I generally
> use plastic tongs/tweezers.  My etchant tank is an ice cream container
> as nitric is plastic safe as well. No heating required, but minor
> ventilation is, it self agitates due to some bubbling during etching. No
> staining etc, clear liquid and does not degrade when dilute. Lasts for
> many years.
>
> Harder to come by in the U.S.A. but if you hold a tertiary degree you
> can buy it from lab chemical supply companies. I am not in the U.S.A.
> and obtain it direct from my old University in carboyles.
>
> I mix down the concentrated stuff to 1.2 Sp. grav to 1.22 Sp grav. for a
> fresh batch as required (acid adds to water). Resultant etch in 5 to 8
> mins double sided, 1 oz. Detail traces to 8 mils using the toner
> transfer/foiling method. No heating or agitation required. Suitable for
> quick and dirty sharpie marker traces, black or silver pens, silver is
> better. Black ink needs to be dried properly (hot air speeds that).
>
> The waste is acidified copper nitrate which is  not a hazmat. Good for
> drain cleaning/sewer lines, anti fungal use etc.

What dilution of acid with water in terms of volume is that?