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

When using muriatic acid and hydrogen peroxide, the etching time mostly depends on the concentration of hydrogen peroxide used.  I usually get 12% peroxide from a beauty supply store.  With this concentration mixed 2 to one with muriatic acid the etch time is around 2 to 3 minutes.  This is a very exothermic reaction, and the solution will get hot very fast..  You really have t o watch closly with this concentration, because it can over etch very quickly.  I usually dilute this down to 6% to get around a 6 minute etch time.  With the 3%  from a drugstore I usually have a 12 to 15 minute etch time.  Peroxide can decrease in concentration after it ages or exposed to air. in a nearly empty container.
DuWayne KV4QB