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Author Topic: Brass etching - FAIL  (Read 50337 times)
jringling
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« Reply #50 on: September 29, 2009, 05:14:37 pm »

I have used regular iodinized salt with no problems. Is your plate etching at all, or is the entire plate etching evenly? Are you suspending the anode/cathodes in a tank? If so, how far apart?

I have had horrible results with the sharpie as a mask. You may want to try fingernail polish.

Could you post pictures of your set-up. With pictures, we may spot something that is out of place...
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Reckless Engineer
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« Reply #51 on: September 29, 2009, 07:03:32 pm »

The formentioned setup works for me a treat thanks Wink

If im honest i wasnt expecting much. I used the battery of my cordless drill with an old drill motor, the motor ran for about 2o seconds then stopped but plenty of bubbles still! id gone about 0.25mm deep in 5 minutes. not bad for table salt and water in an old hand cream pot that hadnt even been rinsed out lol.

Cheers guys thumbs up from me.
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von Corax
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« Reply #52 on: September 30, 2009, 04:40:58 am »

does anyone of you fine ladies or gents have any idea were i may purchase pure salt from in the UK

As I understand it, kosher salt is near-enough pure NaCl as makes no difference. You should be able to find it in any decent grocery store, as it is gaining popularity in non-Jewish kitchens for its purity, milder taste and easier-handling texture.
« Last Edit: September 30, 2009, 04:43:10 am by von Corax » Logged

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planish09
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« Reply #53 on: September 30, 2009, 07:53:56 am »

many thanks will get on to it and take a picture this weekend
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Professor Higgins
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« Reply #54 on: October 16, 2009, 11:15:57 am »

Ive recently been having a go at etching but Im not getting the results I expect.  I am getting an etch but it only seems to go so deep then stops.  I also dont seem to be plating the cathode with copper as I expected, what Im getting is a black deposit that I think is zinc as the etched surface of the brass plate is copper coloured rather than the yellower brass.

Ive tried both copper sulphate and salt but both seem to give the same results. 

For power Im using a bench PSU that allows me to control both voltage and current and monitor whats being used too.  When I start the process the voltage used is around 2v and the current is clamped (limited to whatever I set, in this case 3.5 amps but it would like more as the psu indicates this.  After awhile though the voltage starts to rise and once it reached the max Ive set the current being used drops to about 2 amps where it will happily sit for hours.  At that point it doesnt appear to etch any more.

Any suggestions ?
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jringling
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« Reply #55 on: October 16, 2009, 12:39:04 pm »

Are there any other metals in the solution, such as the hanger for either plate? Are both the anode and cathode brass?

After the etching has stopped, have you pulled the etch piece and rinsed the oxidation from the areas to be etched?

After the etch has stopped, can you increase the amps?
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Professor Damien Tremens
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« Reply #56 on: October 17, 2009, 12:09:02 am »

I would highly recommend that you pause the etching every 15-20 minutes, take  out the item being etched,
and brush /rinse it off in plain water (using the kitchen sink and tap water is fine) with a soft bristled brush.
In addition to removing any sediments or other deposits on the surface of the item being etched, it also lets
you examine the progress and check to see that the masking is not breaking down, the depth of the etch, etc.

In addition, are you using any kind of method to keep the etching solution in motion, like an aquarium bubble bar?
This helps to keep a fresh flow of etching solution passing by fresh metal.
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Wisconsin Platt
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« Reply #57 on: October 21, 2009, 08:47:28 pm »

Some lazer printers dont work Sad specifically brother brand ones, perhaps you could try different paper?

Dear.  God.  I wish I'd known this sooner.   <Shakes fist at the Brother Laser Printer sitting next to him>  I mean, it was still a good buy, but one of the reasons I wanted a laser printer was to print off masks.

Piffle!
« Last Edit: October 21, 2009, 08:49:42 pm by Wisconsin Platt » Logged

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JingleJoe
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« Reply #58 on: October 22, 2009, 12:08:02 am »

Some lazer printers dont work Sad specifically brother brand ones, perhaps you could try different paper?

Dear.  God.  I wish I'd known this sooner.   <Shakes fist at the Brother Laser Printer sitting next to him>  I mean, it was still a good buy, but one of the reasons I wanted a laser printer was to print off masks.

Piffle!
I am also shaking my fist at the useless brother lazer printer that has been sitting next to me for almost a whole bloody year! I can't shift the thing, no one wants to buy it! Sad
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Wisconsin Platt
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« Reply #59 on: October 22, 2009, 02:26:53 am »

Some lazer printers dont work Sad specifically brother brand ones, perhaps you could try different paper?

Dear.  God.  I wish I'd known this sooner.   <Shakes fist at the Brother Laser Printer sitting next to him>  I mean, it was still a good buy, but one of the reasons I wanted a laser printer was to print off masks.

Piffle!
I am also shaking my fist at the useless brother lazer printer that has been sitting next to me for almost a whole bloody year! I can't shift the thing, no one wants to buy it! Sad

At least it gives me hope that I *CAN* etch something.  I was quite put out that I couldn't get the bleedin' toner to transfer. I kept figuring I wasn't cleaning the metal enough.  Guess I'll try again with someone else's printer/copier.
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Major Twangy Rubber
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« Reply #60 on: February 27, 2010, 08:26:15 pm »

Many apologies for the thread necromancy, but I wanted to clarify a specific point mentioned earlier.

I'm attempting to use the toner/salt water method, but I have grave concerns that I'm "doing it wrong" - as on both attempts so far the toner has practically erupted from the surface of my work piece in a matter of seconds Shocked

Further up the thread, it's been said that oxidation forms on your work piece and bubbles rise from the "other" plate (or big brass screw and offcuts of brass from other work in my case). Is this the correct thing to look for?

My confusion arises because I'm using the molex connector on a PC PSU, which is termed "+12V", as one terminal and the ground as the other. In the galvanic etching scenario - which terminal should I be using as the Positive - "+12V" (yellow) or "ground" (black)? I've read conflicting accounts of what the "+" in "+12V" actually means in a PSU, so could someone please be kind enough to let me know what I should be doing?

Cheesy
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Professor Damien Tremens
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« Reply #61 on: February 28, 2010, 05:31:03 am »

Many apologies for the thread necromancy, but I wanted to clarify a specific point mentioned earlier.

I'm attempting to use the toner/salt water method, but I have grave concerns that I'm "doing it wrong" - as on both attempts so far the toner has practically erupted from the surface of my work piece in a matter of seconds Shocked

Further up the thread, it's been said that oxidation forms on your work piece and bubbles rise from the "other" plate (or big brass screw and offcuts of brass from other work in my case). Is this the correct thing to look for?

My confusion arises because I'm using the molex connector on a PC PSU, which is termed "+12V", as one terminal and the ground as the other. In the galvanic etching scenario - which terminal should I be using as the Positive - "+12V" (yellow) or "ground" (black)? I've read conflicting accounts of what the "+" in "+12V" actually means in a PSU, so could someone please be kind enough to let me know what I should be doing?

Cheesy


If the bubbles are forming on your cathode plate (the one that you are *not* trying to etch), you have your positive and negative hooked up backwards.

You want the positive (+) hooked up to the part you are etching (anode), and the negative (-) hooked up to the cathode plate. The bubbles should form on the surface of the metal being etched. In some cases, that actually is an issue if they do not "break away" and allow for fresh etching, as the bubble itself can act as a resist or masking. An example of this effect can be seen here:
Spoiler (click to show/hide)
You can see the series of pits that can form, instead of the smooth edges that should be created. Compare the line quality at the bottom left to the quality at the top right in the image. The rougher, pitted appearance is due to the bubbles staying in place for a long period of time. This typically is only an issue on very fine detail sections, not on areas where there is a large solid section being etched.

One other refinement to be aware of. Ideally the cathode plate should be the same size, if not larger, than the anode. They also should be parallel to each other. If you have a large area being etched, but only a small cathode in relation to the anode, you will get a stronger etch in the area closest to the cathode, and it will weaken as it gets further away. I personally use a full 4" by 10" sheet of .02" thick copper as a cathode (which is the maximum size I typically work with in my setup) so my entire anode is "covered".
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jringling
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« Reply #62 on: February 28, 2010, 06:05:24 am »



If the bubbles are forming on your cathode plate (the one that you are *not* trying to etch), you have your positive and negative hooked up backwards.

You want the positive (+) hooked up to the part you are etching (anode), and the negative (-) hooked up to the cathode plate. The bubbles should form on the surface of the metal being etched. In some cases, that actually is an issue if they do not "break away" and allow for fresh etching, as the bubble itself can act as a resist or masking. An example of this effect can be seen here:
Spoiler (click to show/hide)
You can see the series of pits that can form, instead of the smooth edges that should be created. Compare the line quality at the bottom left to the quality at the top right in the image. The rougher, pitted appearance is due to the bubbles staying in place for a long period of time. This typically is only an issue on very fine detail sections, not on areas where there is a large solid section being etched.

One other refinement to be aware of. Ideally the cathode plate should be the same size, if not larger, than the anode. They also should be parallel to each other. If you have a large area being etched, but only a small cathode in relation to the anode, you will get a stronger etch in the area closest to the cathode, and it will weaken as it gets further away. I personally use a full 4" by 10" sheet of .02" thick copper as a cathode (which is the maximum size I typically work with in my setup) so my entire anode is "covered".
[/quote]

I agree with everything said above... but now I am confused... When etching brass, I do not get any bubbles... I use a copper sulfate solution, so this could be the difference. I do use a bubbler under the piece being etched as it helps remove the oxidized layer and speeds the etch along.

I have recently been etching stainless steel. When I etch ss, I get major bubbling off of the negative plate, not the etched piece. This is in a saltwater solution, using stainless for all pieces in the tank...  Why do I gat bubbles in one and not the other?

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Professor Damien Tremens
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« Reply #63 on: February 28, 2010, 06:17:25 am »

I agree with everything said above... but now I am confused... When etching brass, I do not get any bubbles... I use a copper sulfate solution, so this could be the difference. I do use a bubbler under the piece being etched as it helps remove the oxidized layer and speeds the etch along.

I have recently been etching stainless steel. When I etch ss, I get major bubbling off of the negative plate, not the etched piece. This is in a saltwater solution, using stainless for all pieces in the tank...  Why do I gat bubbles in one and not the other?

I don't know why it would bubble on one and not the other, but I personally do not turn on the bubble bar until I have a solid stream of bubbles
coming up from the etching brass. Sometimes I have to tweak the batteries, wiring alligator clips, or other minor areas before it starts to bubble,
but it is very noticeable when it does finally start up. I only use an electric/saltwater setup, so this could be the difference.
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Major Twangy Rubber
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« Reply #64 on: February 28, 2010, 04:41:43 pm »

Thanks for the clarification!

However I'm still a little confused as to what's going on in my setup... whilst I'm getting bubbles arising (very strongly, it looks like a soluable aspirin!) from the piece that I'm wanting etched, there doesn't seem to be any oxidation occurring on that piece - it's all on the non-etching piece!? After my second toner mask shredded itself off the surface I tried dunking a scrap piece of brass as the anode to see what would happen; after about 5 minutes of immersion, with fizzing bubbles arising from it, there was *no* oxidation at all on the anode - but swooshing the cathode about deposited clouds of brown sludge into my salt water.

If jringling says that he gets "major bubbling off the negative plate, not the etched piece" and I get the reverse but no apparent etching occurring, should I assume I've got mine the wrong way round anyway?

I'm going to give it another bash in about an hour, so I'll try it the "other way round" anyway (it can't hurt!) and I'll report my findings later on.

Smiley
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jringling
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« Reply #65 on: February 28, 2010, 04:51:44 pm »

It took me awhile to remember that "The piece being etched goes to the Positive"

P & P,  piece and positive... This took me months to remember this...
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JingleJoe
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« Reply #66 on: February 28, 2010, 05:44:01 pm »

I must admit I do have to keep going back to the little tutorial I wrote to make sure I have the polarity right Roll Eyes
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jringling
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« Reply #67 on: February 28, 2010, 05:51:36 pm »

I must admit I do have to keep going back to the little tutorial I wrote to make sure I have the polarity right Roll Eyes
That's exactly what I had to do until I memorized P&P...

 Grin
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Major Twangy Rubber
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« Reply #68 on: February 28, 2010, 07:29:48 pm »

OK, I had another crack at it and it would appear that the "+12V" connector is the positive in my setup! Cheesy

Using that as the +ve, my toner resist stayed in one piece and I managed to get a very shallow etch. Bubbles rose from my cathode, not the piece being etched (!?). Looks like that is the way to go, but I need to tweak the system to get it better:

Try another printer and maybe a laminator to make the toner transfer better.
Try the citric acid (?) addition to try and cut down on the oxidation layer - I had to scrub it clean every few minutes! Malt vinegar didn't make any difference, but that's all I had to hand to experiment with  Tongue
Use a proper cathode plate, rather than scrap bits!
Use 2 croc clips per plate to get a better current flow?

Thanks for the pointers guys, I appreciate it!
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jringling
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« Reply #69 on: February 28, 2010, 08:04:14 pm »

OK, I had another crack at it and it would appear that the "+12V" connector is the positive in my setup! Cheesy

Using that as the +ve, my toner resist stayed in one piece and I managed to get a very shallow etch. Bubbles rose from my cathode, not the piece being etched (!?). Looks like that is the way to go, but I need to tweak the system to get it better:

Try another printer and maybe a laminator to make the toner transfer better.
Try the citric acid (?) addition to try and cut down on the oxidation layer - I had to scrub it clean every few minutes! Malt vinegar didn't make any difference, but that's all I had to hand to experiment with  Tongue
Use a proper cathode plate, rather than scrap bits!
Use 2 croc clips per plate to get a better current flow?

Thanks for the pointers guys, I appreciate it!
Citric acid? I may have to look into this... With the brass I use I have to clear away the oxidized layer 2 or 3 times to keep it going quickly. If I don't, it still etches fine, just slower...
A warm bath also etches faster...

Also keep in mind... it isn't the volts that direct the etching, it is the amps. I use a 6 amp 12 v car charger without any load in-line, so the etching sees 8-10 amps and the charger trips its thermal circuit breaker every 10 minutes or so... but I get good deep etching...

good luck and keep us posted...
-Jerry
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JingleJoe
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« Reply #70 on: February 28, 2010, 09:30:15 pm »

Use 2 croc clips per plate to get a better current flow?
Now thats just silly Roll Eyes Your current is not dependant on the number of crocodile clips! It is dependant on how many amps your power supply can deliver and the concentration of your salt solution and the distance between yourt electrodes. I have had great results with a 1 Amp/12 Volt power supply, connected through a big 10 ohm power resistor to prevent overheating Smiley
« Last Edit: February 28, 2010, 09:32:50 pm by JingleJoe » Logged
Major Twangy Rubber
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« Reply #71 on: March 01, 2010, 01:07:33 am »

I'll rephrase that: a more uniform current flow?

I was picking up on a page that I'd read where someone had constructed a sort of mesh out of brazing rods in order to support their piece and provide a "better contact" to their battery, or something. As I'm using a single croc clip the contact area is practically zero (unless I file the teeth off!) If it's not important, I'll ignore it Wink

The PSU should be good for about 20 amps @ 12V. I picked the 12V rail as it's got the largest current capacity, and in lieu of an ammeter I have a watt meter at the wall socket instead (didn't hit more than 80W at any point during this piece, no matter how close I brought the plates).
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oldskoolpunk
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« Reply #72 on: April 11, 2010, 07:02:19 pm »

My confusion arises because I'm using the molex connector on a PC PSU, which is termed "+12V", as one terminal and the ground as the other. In the galvanic etching scenario - which terminal should I be using as the Positive - "+12V" (yellow) or "ground" (black)? I've read conflicting accounts of what the "+" in "+12V" actually means in a PSU, so could someone please be kind enough to let me know what I should be doing?


Many PC PSUs won't start without a load on the +5 output.  See How to Convert a Computer ATX Power Supply to a Lab Power Supply. Notice the 10 ohm, 10 watt resistor between +5 and GND. 
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JingleJoe
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« Reply #73 on: April 12, 2010, 12:28:22 am »

My confusion arises because I'm using the molex connector on a PC PSU, which is termed "+12V", as one terminal and the ground as the other. In the galvanic etching scenario - which terminal should I be using as the Positive - "+12V" (yellow) or "ground" (black)? I've read conflicting accounts of what the "+" in "+12V" actually means in a PSU, so could someone please be kind enough to let me know what I should be doing?


Many PC PSUs won't start without a load on the +5 output.  See How to Convert a Computer ATX Power Supply to a Lab Power Supply. Notice the 10 ohm, 10 watt resistor between +5 and GND. 

I am acctually part way through doing that right now Cheesy Some need a load on the 3volt rail too and in others the wiring colours are different, way to be maddeningly unhelpful computer parts makers Roll Eyes
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rovingjack
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« Reply #74 on: May 26, 2010, 07:39:01 am »

I was all set to get miffed and grumble about false advertising by hardware dealers. Se I was giving this a try with a peice of brass hardware and a long wood screw. I hooked up the brass to the - and the wood screw to the + and bubbles formed and went wild on my brass hardware (blowing away my attempted mask in a picosecond. but since my brass was half in and half out of the solution I figured there would be a clear mark as to where the etch occured.

I let it sit for a bit, and came back to it to discover, a two tone object. half brassy and half silvery. I was thinking it was a brass plated steel... now I wonder if it's possable that I just plated zinc or chrome or something onto the brass. I apparently had the set up backwards according to the posts above.

also what sort of resist is really dependable? I used a grease pencil, and that was fairly useless, and I tried a sharpy and that didn't stick. Is it because I wired it all backwards or are they liable to be ineffective? loath as I am to try I may pick up a bottle of cheap nail polish at the dollar store tomorrow and some othe brass bits at the hardware store for experimentation with.
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