Sunday, April 27, 2008

Etching Metal - Safety FIRST

Here's my focus on the results of some safety research done about using muriatic acid and hydrogen peroxide to make a substitue for ferric chloride, the PCB etchant no longer available from Radio Shack for etching computer PCB circuit boards.

- First, let me say that I used to make my own soap using hot sodium chloride (lye) and hot oils to create the soap molecules, am not afraid of toxic or dangerous materials and understand that safety is foremost and substances can be respected and still be used.

- Second, safety is top of the list with me, when using machinery, drills, extremely high temperature kilns and torches. But it doesn't stop me from using things that might injure me if I don't pay appropriate attention to safety concerns.

I am seeing sites recommending using the muriatic acid plus hydrogen peroxide mixture, without a lot of safety information. In Europe, chlorine bleach is treated as a toxic substance while in America it can be purchased at the grocery store. All that taken into account, here is a list of safety and must-follow ideas if you plan to use muriatic acid and hydrogen peroxide to etch copper, brass or nickel items.

Safety is always the highest priority. Your hands, eyes and lungs are important and should always be protected. Your children, pets and plumbing are also important.

USE EXTREME CAUTION with etching solution, be focused on what you are doing and never leave it and walk away for any reason - this method of etching demands more respect than using ferric chloride, the etchant no longer available through Radio Shack, but which is still available at Rio Grande supplies (see link below). This etchant is much more agressive and dangerous to skin and eyes. Muriatic acid will eat through clothing and skin, even as a mist or tiny droplets. Always wear protective equipment, goggles and gloves, and keep a box of baking soda (sodium bicarbonate) handy to neutralize any spills and to put on your skin, to wipe down the work area - any foaming shows where the acid has spilled.

1 FIRST locate and keep available Baking Soda (Bicarbonate) at all times for neutralizing acid and etchant spills
3 Don't use a metal container.
4 Do not use in your kitchen and keep away from food and beverages
5 Keep away from stainless steel - sinks, appliances
6 NEVER put down the drain or flush in the toilet - will eat pipes and very bad for septic tanks - copper ions very bad for fish in streams
7 Muriatic acid creates fumes - only use outdoors and do not inhale fumes
8 Wear safety goggles, latex or nitrile gloves, long sleeves, no open toed shoes - ABSOLUTELY necessary at all times
9 Wear leather or vinyl apron over clothes
10 Have a fan blowing fumes AWAY from you (yes, even outdoors) for ventilation
11 Keep the garden hose handy at all times to flush any splashes or spills
12 Don't use anything made of nylon in the etching bath, it will turn to sticky mush
13 Stainless steel tools (tongs, tweezers, burnishers, etc) will be instantly etched and dulled by the etching solution - use plastic or bamboo only
14 TOSS the gloves you use and rinse the vinyl apron well and hang to drip dry - the etching solution concentrates as it dries

Have a large container of cold water nearby to place etched metal in when degree of etching is obtained, then place into container with baking soda water and (still wearing gloves) sprinkle more baking soda on etched metal to completely neutralize it

Do NOT store in an open container as it will continue to give off corrosive fumes and vapors
Do NOT store in bottles, jars or containers that look like they might contain food or have food or drink labels on them
Recommend putting POISON-DO NOT DRINK OR SPILL labels on plastic lidded container

Do not dispose of used etchant by pouring into the environment - the copper ions are bad for fish and wildlife. Dispose as a hazardous substance.
If after reading all this, you prefer to use ferric chloride, a milder etchant that used to be available from Radio Shack, here is one supplier and how you can find it (there are others too):
RIO GRANDE - ETCHING SOLUTION LOCATION (you will need an USERID to log in, or call them on their 800 number)

Here are some links that talk about etching computer boards in copper and etching for model trains and spaceships, that contain much of this information:
Etching Links:!--A-better-etc/

PLEASE be careful and use safe methods when etching metal. Your eyes, hands, plumbing, children, pets, garden and the natural world (not necessarily in this order) are worth protecting. If you have questions or comments please post.

Safety in Storage of Metal Etching Supplies - took a large plastic storage tub, the big one-piece ones with snap on lids, and am storing the etching solutions, potions and supplies in it with the lid on tightly. If anything gets knocked over or accidently spills it will be contained inside the plastic tub. Also those tubs have holes through the handles so a lock can be put on them, may not go that far but if the tub goes to the garage or shed later might do that, with a big sign on the lid describing the contents clearly.
Safety rules for metal etching.
Eye protection - goggles Clothing protection - leather or vinyl apron Skin protection - latex gloves, long sleeved shirt, no open toed shoes No metal containers, plastic only No metal tongs or tweezers, plastic or bamboo only Cover work surface with plastic Have baking soda (neutralizer) mixture handy at all times Don't breathe fumes, only use outdoors Don't pour residue in drains, will eat plumbing and septic tanks Always add acid to water! Avoid splashing Keep away from pets and children - label clearly and keep locked away

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