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

First of all, distilling hydrogen peroxide from pharmacy grade 3% VOLUME peroxide is relatively easy. I posted it some time ago and some one recently said it as well. It's by freezing and throwing away the ice that forms.

∗∗∗∗ safety ∗∗∗∗
You need to be extremely careful in handling this concentrated stuff. You can only reach about 40 some odd percent concentration by freezing. Still, its "dangerous". I've accidentally had few droplets hit my finger (Yes I should have been wearing my chemical gloves but I wasn't) and the skin where the droplet hit, the skin immediately turned white, chemical burn. Then the liquid penetrated into the dermis, layer of skin where there are blood vessels and nerves. And the painful stinging sensation from the peroxide burn was really intense. It was good that I had the sensation. Had it stopped, then it would have meant that my finger would have to been amputated...


∗∗∗∗Another safety aspect of handling peroxide∗∗∗∗
DO NOT EXPOSE TO UV OR EVEN BLUISH LIGHT (florescent light, sunlight is a big NO NO).

DO NOT LET IT COME IN CONTACT WITH ANY METAL ESPECIALLY IRON BASED MATERIAL. This includes all stainless steel. Iron act as a catalyst to decompose peroxide into oxygen and water.

Store in clean dark brown bottle but it should not be so airtight
that it can build up pressure. Countless number of explosions have happened because of this most famous is the accidental sinking of Russian super sub the Kursk.

∗∗∗∗ Side note ∗∗∗∗
do not confuse volume concentration such as 3% vol H2O2 with 3% H2O2. big difference. You can not get 90% H2O2 nor can you make it at home unless you know lot about chemistry and have the right equipment.

Concentrating H2O2 by freezing is more than plenty good for your etching need!! Don't make it any more dangerous than need to be.