Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

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.

Ancel