Copper Etching

[Unforgivun]

So yesterday Jeff and I tried our hand at etching copper. I wanted to share my experience here so that others do not make the same mistakes I did.

For those of you not familiar with the process its pretty simple. Basically you have an etchant that eats into the metal that you're etching. Then you have a resist, the resist protects the metal from the etchant so that a design can be etched into the piece.

Etchant solutions can be comprised of strong salt solutions or they can be acids that eat at the copper itself.

The etchant we used was Ferric Chloride. We used it on a small piece of 18 gauge or so copper. The resist we used was plain old sharpie markers.

Here is what we learned. Fresh Ferric Chloride works FAST. After 40 minutes of etching, the design was fairly pronounced. Its important to sort of "swish" the piece in the solution to allow the bits to sort of fall off. I can't comment on any other etchants at the moment as we haven't tried them.

The resist we used was plain old Sharpie markers. What we learned about the sharpie markers as resist is that they aren't all that reliable. The design itself held fine, but the edges deteriorated a lot. That made the design sort of rough around the edges.

Anyway, you have to disable the etchant once you remove the piece. We used ammonia, but we have since read (didn't try it) that soapy water will do that.

Once the piece was done we cleaned it in a mild sufuric acid solution to clean it up, and then pickled it in liver of sulfur (sulfurated potash).

Here is the final result. Noticed the design edges where the sharpie eroded rather than resisted.







The next attempt will use either oil based paint sharpie, a toner transfer, or an acrylic paint as resist.

[trying-it]

Looks good Blake.

Some additional resist info can be found at link below:

http://www.ganoksin.com/borisat/nenam/gom-etching-champleve.htm


In class last semester we used asphaltum with great results, but the stuff can be a bit messy applying.

I also used clear nail polish with good results.

With either resist I found a small set of jeweler screwdrivers works real good for resist scratching tooling.

A couple examples of my first tries:



Have fun and play safe!

[BIGGUNDOCTOR]

I am currently reading a book from the 1920's on etching. Lots of resist, and echant formulas.

[trying-it]

Doc you going to share book title and a few of the recipes???????? :rolleyes:

1 of these days "photographic etching" will be tried here. Seen it done, just not by me yet! Same process used in industry for printed circuit boards, etc.

Think family photos etched on metal would make great Xmas ornaments and/or gifts.

[ianinsa]

Hi All,
In this day and age the most effective rewsist is signage vinyl, available from your local signage shop! they can even cut it for you with their computerised vinyl cutters.
For mordant(the acid that does the etch) I have recipies(tried and tested)for most metals including 316s/s just PM me & I'll send, I have posted them before. If you warm the mordant you get quicker results, use a feather to brush off bubbles on your job for a "crisper " look . Wear a respirator, Remember, if it eats metal it Ain't good for You !!!!

[ianinsa]

Sorry I could not find earlier posts easilly so, the most effective mordant that I have found for Copper,brass and bronze is 3 parts water to 1 part nitric acid , this will etch 1mm deep in 8-10mins , it works for sterling silver,nickel silver pewter and other Zinc based alloys too. For Monel use 1 part nitric to 1 part acetic acid And Aluminium use 3 parts water to 1 part Hydrochloric acid , Stainless steel use 2 parts nitric to 3 parts Hydrochloric acid(Be extremely carefull with this stuffthe slightest wiff of the fumes will rust the crap out any metal nearby ).

To get the Vinyl to stick down "bubble free" first spray your metal with a light coat of dishwash water mix , this allows for "squeegeing" and some repositioning.

When cleaning up with soapy water afterwards add some bicarbonate of soda to netralise
the acid.


When etching take extreme care the mordants and the fumes as they are hazardous to you ,your loved ones and the environment!!!!!!!!!!!!!!!

[tzonoqua]

I used to do a lot of copper etching at college. Great fun!! I second what Ian says, nitric works great, warm bath, agitate or use a brush to move the bubbles around, pay attention to health and safety practice, wear ppe!! We used to use nail polish to draw designs on the metal, then remove afterwards with acetone.

I also used to work as a signmaker, and cut out vinyl designs to etch, great for logos etc, and at the moment where I work in a school we use photoetch boards for printed circuit boards, transfer the image in a light box with an a acetate transfer that has had the image photocopied onto it, then washed through a developer to reveal the image, then etched in ferric chloride. Although we are just doing circuit boards with this process, with this method the outcomes are limitless!!!

Be sure to dispose of your acids safely, either by neutralizing or taking to a hazardous waste depot.

[pkrankow]

If you are using a photo resist, and your mask is halftoned (can be done in photoshop) you can get photograph reproduction, well, newspaper equivalent.

Very interesting.

Phil

[etech669]

Hi I've had similar failures with Sharpie pens but had some excellent results with "Dalo Etchant Resist pens" used for circuit board prototypes AU$6 (Not suitable for ammonium persulphate etchant)
Another product available here in Aus. is "Press & Peel PCB Film", Simply photocopy or laser print your design onto the film, cut to size, iron onto your copper project & etch. Good for larger designs (200mm x 280mm) pack of 5 sheets AU$32

Cheers.

[Unforgivun]

I'm familiar with PCB BLUE, but I've seen a few tutorials online showing the same basic thing using a regular transparency film. IF the transparency film works that would lower the cost of a "printed" design significantly as they only cost around US$0.30 each.

[Pulsepushthepopulace]

Muratic acid and hydrogen peroxide is another avenue of approach... More volatile, but keeps well, easier to get ahold of, and has less of an environmental impact in comparison to copper sulfate....


staedler dry erase marker -> Red...

[ToolSteel]

Kosher Salt
In the past, I've dissolved as much salt as hot water will hold, put it in a crockpot on low and connected the anode/cathode. A few hours later, I got a DEEP sharp etch on copper. In fact, this was stronger than anything else I tried... and I've tried Muriatic Acid and Bisodium Sulfate... separately.

[Bentiron1946]

A note of caution, please don't just dump the used etch solution on the ground, dump down the drain as it will pollute the ground and water. Salt will kill plants and sterilize the soil and the copper is a contaminate too. When you dump it down the drain it may end up in a septic system and pollute the the ground water as it filters through the soil and if you are connected to a city wide system you will get some dilution but eventually it will be added to the environment so take you left over chemicals to a proper hazardous disposal site, do not just dump them in the regular trash or down the drain. We only have one planet to call home.

[Unforgivun]

Most facilities that accept used motor oil will accept old etchant solutions as well.