Copper Etching Discussion - Page 3

menty666 · #61 2011-02-25, 10:28pm

Thanks folks

I still need to pop by the pet store for a cheap aquarium pump.

Holaday · #62 2011-05-24, 1:39pm

David,
the info you provided some time ago (quoted below) is what I have been searching for. I have read in a couple of places that a dangerous gas is emitted if higher voltage is used (more than the D cell batteries I think is meant). Several of my students are "improving" on the instruction from Art Jewelry Magazine. They are using a rechargeable 9v lantern battery. I am concerned that this "improvement"..... while it is working GREAT, might be not so good for health reasons. Am I understanding this correctly? Should I tell them to STOP? I did mention possible dangers but until I found your post, I couldn't name the gas.
Thanks for any further input you can pass along.
I plan to use rechargeable D batteries in tandem, and a battery holder to hook them together.
Carol

"So the slight amount of sludge you end up with is copper chloride. During the electrolysis process, you bubbled off hydrogen and chlorine gas. Copper chloride is none too friendly, either.
************************************************** ***********************************
Copper chloride= cupric chloride CuCl2[/quote]

houptdavid · #63 2011-05-25, 11:38am

Carol as long as it's a well ventilated space everything should be fine, just like charging a car battery you wouldn't want to do it in a tightly enclosed space

Holaday · #64 2011-05-25, 12:14pm

Thanks David,
I will warn them AGAIN about the need for VERY GOOD ventilation during etching process. I am going to set up my own etching bath in my studio inside a fume hood style system.

I haven't yet decided between using four rechargeable "D" batteries in a holder, or the rechargeable 9v lantern battery. Cost for set-up seems similar (including chargers). Or perhaps I should look into Tink's electro-plating system. So many choices, so much information.

I have successfully etched with ferric chloride.... too messy .... and sodium persulfate, nice etch but slow.

Thanks again for the info.

SilverSage · #65 2011-06-05, 8:58am

I would like to try this. At the moment, I have no method preference. Any recommendation for which would be best to try?

Holaday · #66 2011-06-05, 9:58am

Julie,
I expect there are many "best, easiest, cheapest, safest, etc." ways to etch metal. Ask ten people who have done it and you will get ten different "favorite" methods no doubt..

I have decided to go with salt water and four rechargeable D batteries (two might do the job just as well). Ordered the top quality batteries and charger from Amazon.com. I bought an aquarium pump and a heavy (doesn't float) bubbler stone at a pet supply store. I plan to do this with EXCELLENT ventilation and will dispose of the used etchant at the hazardous waste dump. This method (minus the bubbler and with one battery) was described in great detail in the November 2008 issue of Art Jewelry magazine. Reprints might be available on their web site.

Coral Shaffer (owner of www.enamelworksupply.com) has written an extensively researched 56 page spiral bound book that she self published. "Relief Etching for Jewelers and Enamelists" includes instructions, safety info., and the pros and cons for a great variety of techniques and chemicals. She consulted safety experts and chemists and includes their warnings. A chart on page 50 makes it easy to compare the variables.

I asked Coral why she warns against using a 6v battery and she replied "According to the safety guys the batteries in series increase the amperage without increasing the voltage. I still have trouble visualizing the difference but apparently they can. And they warn that anything above the 1.5 volts has potential danger involved. Also I found that using higher voltage tends to degrade the resist. That may not matter for a short, shallow etch but I'm always going for a deep etch and need to keep the resist intact."

I am interested in hearing what others have to say about their preferred methods.

SilverSage · #67 2011-06-05, 11:06am

Thanks so much for your input Carol! While I do have limited funds, cheapest isn't necessarily my goal. The aquarium bubble sounds good to me, but I do worry about waste disposal. If I can figure which method works best (and perhaps without least staining of workspace, etc.) for a nice deep etch I'm willing to go that way. In the long run, it is less expensive than trying the cheapest, finding out it doesn't quite do what I want, and then ending up spending $$ on the next best method, etc.
I will go research the link you provided. Thanks so much!

houptdavid · #68 2011-06-17, 8:42pm

Julie if you go with the rectifier/powersupply and the copper sulphate you can electroform too!

SilverSage · #69 2011-06-30, 7:41am

Do these methods work with silver also, or will I need another method for that?

houptdavid · #70 2011-07-15, 6:35pm

Silver is another solution altogether

alb6094 · #71 2011-07-23, 3:06pm

Bump

Just wanted to say thank you David for putting up such a comprehensive list. Everything I could possibly want to know about etching in one place, you're a doll!

AutEvDesigns · #72 2011-07-23, 7:59pm

I etch copper and brass with the cupric chloride (peroxide with Muratic Acid) and it's extremely inexpensive and works great (for me). Here in MN, anyway, you can get the peroxide for less than $1 and the Muratic Acid for around $5 a gallon at most home improvement/hardware stores. What I like best is:
1) you can recharge the solution by adding peroxide (and occasionally a little more acid) and don't need to throw it out after a few etches
2) it's a relatively transparent (though sometimes dark) solution and is pretty easy to see how your etch is progressing
3) and after the first etch or two the solution gets weak enough that you can throw in a piece of copper or brass over night and get a good etch by morning.
a) I do this in my garage studio. I don't think I'd let it sit for that long in my house
b) it's not really for anyone who wants instant gratification ... at least after you get copper into solution, it's fairly fast (5-15 min for a shallow etch) when it's the Muratic Acid without any copper in solution (and very noxious - ventilate WELL) ... but it's nice when you don't want to babysit your etching.

For resists I have successfully used StazOn ink with rubber stamps, alcohol-based paint pens (from Art Supply stores like Dick Blick), electricians tape, Sharpie Markers (the designs drawn with these seem to disappear the fastest, but browns and reds seem to stick around a little longer than the black ink). I've purchased asphaltum but have been too chicken to open it and try it.

I've read about the salt bath and rectifier and think with the comments and help in this thread I might give that a try!

alb6094 · #73 2011-07-23, 8:49pm

Julie I think yours look wonderful! I have both peroxide and muratic acid (I pickle with MA) and that sounds like a good match for me. I have some rubber stamps and I think I'll find the StazOn Ink and give that a go.

cheng076 · #74 2011-11-11, 11:42am

Batteries in SERIES increase voltage and amperage stay the same. Batteries in PARALLEL increase the amperage and the voltage stays the same as one cell.

Think of voltage as similar to a pressure and amperes as an amount; 12 volts of electrical pressure pushing a quantity, amperes, of electrons thru a circuit.

Holaday · #75 2011-11-12, 9:08am

chen076,
thanks for the clarification... though I am still not entirely clear.

so ..... are 4 D batteries in a battery holder in a serial arrangement?

I found a useful diagram here:
http://electronics.howstuffworks.com...h/battery6.htm

Wish I could say that I now know what I am doing.... It does appear the battery holder is a serial arrangement and therefore delivers 6 volts ... though I am still not certain of this. And if it does, is this any different than simply using a 6 volt lantern battery when it comes to safety issues? I am concerned about this because my students "improved" on the original instructions found in a magazine and are using the lantern battery in their home studios. If I understand Coral's safety instructions, this is not a good idea. Great results however.

AmorphousDesigns · #76 2011-11-12, 10:05am

that battery pack has the batteries in SERIES, each "bottom" of one battery is connected to the "top" of the next one. If it were parallel all the "tops" would be connected and all the "bottoms" would be connected.

Holaday · #77 2011-11-12, 10:08am

Elizabeth,
thanks for confirming my guess re: the battery holder. Now if I could just wrap my mind around the rest of the info.

houptdavid · #78 2011-11-13, 6:43pm

Julie nice job, do you have a bubbler/air pump?

houptdavid · #79 2011-12-11, 9:55pm

Here is some more info on electroplating...
http://www.archive.org/stream/electr...e/250/mode/2up

I just love old technical books

houptdavid · #80 2013-02-20, 11:20am

Moved and bumped as there have been a lot of questions lately about electroforming

Holaday · #81 2013-02-20, 12:55pm

Thanks David. Seeing as this discussion has been "bumped up", I'll add an update of my own.

Note: This is for electro-etching and not for plating.

Since my last posts in November 2012, I have changed a few things. I am now using a small power source that provides a steady 3 volts (can raise this) at a set 2 amp. Still using salt water but no longer using the aquarium pump. Photos and comments on set-up and results can be seen on my blog (link below my signature). I still might prefer the rectifier/power source with digital read-outs... so that I could (maybe) set the volts lower still.

I am starting to get a handle on the volts/amps (current) thing, but no clue yet as to what is meant by "load". What difference does the size of the anode (the piece) make, and how about the size of the tank in relation to the other variables?

This is a continuing experiment and I enjoy reading everyone's comments, questions, and solutions. Thank you.

houptdavid · #82 2013-02-20, 2:32pm

I have only used the Cupric Chloride etchant (Peroxide/acid) which I wasn't real thrilled with and the Rectifier and Copper sulfate which I can use for both etching and electroforming

The load is referring to the size of the piece and the amount of current it takes

For etching
The anode (etched part) should be the same size or less than the cathode
{But for electroforming the anode should be the same size or larger than the cathode (work) 1:1 to 2:1}

Tank size should be for what fits your work, more important is the distance between the anode and cathode 1-3 " depending on work (again for copper sulfate)

Holaday · #83 2013-02-20, 5:19pm

Thanks once again David.

I have two tanks. One for 2"x3" max and one for 4"x6" max. Smaller tank is working well with a simple power source 3-12V and set 2amp. Have yet to test this power source with the bigger tank. A bit concerned that the larger load might be a problem.... I am guessing at this because the unit does seem to get hotter when the anode has more surface that is being etched away than when it has less... and with all else being unchanged.

I use it with the volts set at lowest option. I would prefer a unit that I can set lower. Perhaps at 1V.

The anode and the cathode are about 1" apart. No complaints about how this is working, just want to know what to expect if I try to use this power source with a larger load.

So much as been written on this topic, you would think there could be no more questions. Perhaps I am over-thinking it.

houptdavid · #84 2013-02-20, 5:30pm

Are you using a saturated salt solution (no more salt will dissolve in the water) as the salt breaks down and you have to renew the tank from time to time

Holaday · #85 2013-02-20, 5:38pm

Yes. In fact, the solution becomes so saturated with crud that I syphon off the clear water after the crud settles before I add more salt.

houptdavid · #86 2013-02-20, 5:58pm

The crud is sodium hydroxide (lye) and Copper chloride

Holaday · #87 2013-02-20, 6:03pm

Good to know. So this is what I put on the label when I take it for hazardous waste disposal? Anything else?
A small amount of etching - small piece, little surface being etched - sure produces a lot of this "crud". Anyone else using the salt water method to etch copper experiencing this?

David, in your opinion, is the copper sulfate option more or less toxic to use and dispose of?

Holaday · #88 2013-03-03, 10:24am

Update on salt water/power source etching experiments. I set up a larger tank for the brass plates I use for roll printing. Used the same small power source with same settings (3V @ 2amp fixed) as shown in previous post. The piece etched at about the same speed as a smaller copper piece in a smaller tank. Lots of by-product produced, AND I had to clean off the cathode several times as black "stuff" built up quickly. Second photo shows cathode with lots of holes punched in it. I have cleaned and sanded off most of the black build-up.

Although the salt water etch is working well, I don't like the amount of "by-product" I am dealing with. I can't find the container of copper sulfate I so carefully stored, so I set-up the smaller tank with sodium bi-sulfate (what I use to pickle silver and copper). I plan to try that one today. I am thinking that since we sometimes add peroxide to this pickle to make a "super" pickle to etch off copper from accidentally copper plated silver, perhaps I can safely add some to speed up this etch if needed. I'd like to heat the solution just a little (pretty cold in the studio right now), but since the etch tank is plastic, I hesitate to put it on a warming tray as I do with the pickle in a Pyrex glass container.

Including photo of piece and cathode in the larger tank as it shows my latest design for the 4"x12" cathode. The 2" X 6" piece is taped to the brass sheet "hanger". This is working well, although I am still searching for the "perfect" tank for this size of piece.

Holaday · #89 2013-03-11, 9:16am

A question for David..

In an earlier post you said - "The crud is sodium hydroxide (lye) and Copper chloride".

My question is... in the salt water/power source technique, do the volts used change what by-products are produced? The reason I ask is that I saw a photo of another etcher's set-up using a single D cell and the water looked very copper colored. After not much etching, mine is much more of a mustard color with quite a bit of "crud" floating... and then settling. I want to properly label the container when I take it to the hazardous waste disposal site.

So many people are using (and sharing) the salt water/power source method because they feel it is "safer" than ferric chloride. Lye as by-product certainly doesn't sound safe to me. In fact, I would add a huge red flag safety warning for that. Or am I over-reacting?

I couldn't find my container of copper sulfate so I set up a small tank with sodium bi-sulfate (pickle) and the small power source set at 3V (as low as it will go). While I love the clear turquoise color of the bath, and there is no "crud" to deal with, it was a very slow etch. This could be because it needs to be warmed up a bit (pretty cold in the studio right now). As soon as I find a glass beaker that I can safely use on a warming tray (as I do with the pickle in a Pyrex bowl), I'll try that. Or maybe I could add some peroxide to it as I do when I need a "super pickle". What do you think?

Thanks for your help with the chemistry of electro etching.

houptdavid · #90 2013-03-11, 4:46pm

I'm no chemist

I just Google the crap out of things.

The byproducts will be the same with the salt water/power source, just takes longer to produce.

I can't find anything on using sodium bi-sulphate [sodium hydrogen sulfate (NaHSO4)] as an electrolyte bath for electroetching/plating

What you are trying to do with the sodium bi-sulfate is basically make Cupric Chloride Etchant. BUT you DO NOT use a power supply. This works best warm and with an air pump.

http://www.ndiprintmaking.ca/forum/i...page;topic=9.0
Cupric Chloride Etch (for copper)

250g Sodium Bisulphate - 1000ml water = 20 Degrees Be / SP 1.16

350g Salt - 1000ml Water = 23 degrees Be / SP 1.1885 (some excess salt)

400 ml Hydrogen Peroxide 12%

Above mixed together

Add 400g Copper Sulphate

* You may need to add a further 200g salt & 100g Copper Sulphate to adjust specific gravity of mix

Final Cupric Chloride Mix = 30 degrees Baume (Heavy Scale) / SP 1.2609