# Etching



## Brento (Jul 26, 2021)

Has anyone done chemical etching before? I was thinking of maybe making a ring for my wife at some point and i was thinking of etching our date on the inside or outside even. Idk much about chemical etching and how much machines or chemicals are to do it.


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## Brento (Jul 26, 2021)

I found a etching kit from McMaster for 101$. I am not sure on doing it yet as i have thought of maybe doing engravings instead with my Gesswein dremel system instead. But id love to hear others opinions or options.


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## RJSakowski (Jul 26, 2021)

I have done a lot of chemical etching of p.c. boards.  Thousands in number.  I used a photo resist to make a mask and ferric chloride for etchant.  

I also etched serial numbers on my 1-2-3 blocks using electrochemical etching with a simple table salt solution for the electrolyte and a Q Tip swab for an electrode.  I used nail polish for a resist and cut the serial numbers into the resist with a CNC laser.








						Etching Steel Using a 2.5 watt Diode Laser
					

I recently purchased five pairs of 1-2-3 blocks. My intention was to use them for setups when machining.  They arrived last week and on first inspection, actually looked reasonably good.  I want to do more thorough metrology but thought that I should serialize them first.  A carbide scribe could...




					www.hobby-machinist.com


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## Brento (Jul 26, 2021)

That is an interesting idea. Not that it is complicated i am sure with the laser it seems a little more involved then what i would like to do. Especially since i dont have a cnc to help with doing print of letters and numbers


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## RJSakowski (Jul 27, 2021)

Brento said:


> That is an interesting idea. Not that it is complicated i am sure with the laser it seems a little more involved then what i would like to do. Especially since i dont have a cnc to help with doing print of letters and numbers


The laser isn't necessary.  The etching pattern can be inscribed in the resist with any tool.  I used it because I wanted precision  and my hands are too shaky to do that kind of work any more.  There are other methods of transferring a pattern.  Photoresist is one.  Artwork would be drawn out and used to make a mask for exposing the resist coated surface which would then be developed using the recommended developer.  Considering that you want to etch the inside of a ring, this most likely wouldn't work though.  I would opt for hand inscribing the resist if your hand is steady enough.

If the ring is precious enough, you may want to take it to a jeweler who has the means to do this kind of work.  Unless , of course, you want it to be made entirely by your hand.


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## Ken226 (Jul 27, 2021)

I made an etching machine about 15 years ago.  It was one of my first projects as a student,  during my first electronics theory class, while working on a degree in mechanical engineering technology.  

I still use it occasionally for marking small tools,  but do most all of my engraving on a CNC mill these days.

The stencils are made with a photo resist film.   I draw a logo, or other info in CAD, then print the logo onto clear overlay film.   I use a light exposure device in a dark room, to expose the photo resist film.   A solution is used to desolve away the photo resist that was protected from exposure by the logo printed on the clear overlay film.

The stencils seem to last for around 50-100 uses.

I made the electrode from a 1" x 3" graphite block.   The contraption still works like a champ.

I purchased all of the hardware to make this thing from the local Radio Shack when I lived in New Mexico.   I'm not sure if Radio Shack even still exists.


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## brino (Jul 27, 2021)

Ken226 said:


> I made an etching machine about 15 years ago. It was one of my first projects as a student, during my first electronics theory class, while working on a degree in mechanical engineering technology.


I would really like to know more about this system; and see some more pictures of the stencils, info of the resist used, and some pictures of results. Got any schematics you can share?

Perhaps a new thread (with a link from here to find it) so that @Brento can have his thread back.

Thanks!

-brino


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## Ken226 (Jul 27, 2021)

Sure.  I'll start a new thread.   Once it's posted,  I'll come back here and post a link.


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## Ken226 (Jul 27, 2021)

Etching/marking machine.
					

At the request of a member in another thread,  here is some info on my etching machine.  I built this quite awhile back, and no longer have the exact part#s, etc but the design is simple enough.     I bought photo-resist  stencils, developing solution and the exposing light from etch-o-matic...




					www.hobby-machinist.com


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## Brento (Jul 27, 2021)

I am fine with the conversation bc his machine is kind of what i was looking for. As i said McMaster sells a unit for 101$ as a kit for transfer pads and the such. That kit is only for aluminum and brass i believe but for a heftier price you can get a bigger kit and do up to stainless. If i got into it i would just buy the stuff for the stainless separate.


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## Tomzo (Jul 27, 2021)

My family runs a nameplate manufacturing facility ( www.knpco.com ) and I worked there as a kid and right out of college.   Etching and chemical milling was and is one of the company's specialties.   While I have not done any myself for 30 or so years, I can share the following:

-  You need the right chemical for the metal.   Brass and aluminum do well with ferric chloride as I recall, but make sure you get the right stuff.   Ferric chloride will stain the heck out of everything you get it on, so be warned.
-  Getting a good print of the resist is important - if you don't get it right the acid will bleed under the resist and look like crap.   Surface prep is important and getting the resist chemistry right - along with proper curing - are key.
-  I have done photoresist and screen printed resists.   For us, screen printed resists were more reliable as the process of laying down the photoresist, getting it exposed and "developed" right, and then cleaning the part is much more challenging.
-  Doing one offs is tricky - and on a surface like a ring I think it will be hard to get any sort of resist applied especially on the inside
-  For something like this we might have gone with an engraved solution - unless we had a dozen rings and the customer only needed 8.   We anticipate a certain level of loss when doing these processes.

That is my $0.02!

Tom


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## Shotgun (Jul 27, 2021)

RJSakowski said:


> The laser isn't necessary.  The etching pattern can be inscribed in the resist with any tool.  I used it because I wanted precision  and my hands are too shaky to do that kind of work any more.  There are other methods of transferring a pattern.  Photoresist is one.  Artwork would be drawn out and used to make a mask for exposing the resist coated surface which would then be developed using the recommended developer.  Considering that you want to etch the inside of a ring, this most likely wouldn't work though.  I would opt for hand inscribing the resist if your hand is steady enough.
> 
> If the ring is precious enough, you may want to take it to a jeweler who has the means to do this kind of work.  Unless , of course, you want it to be made entirely by your hand.


Another option for the resist:

Print a mirror image of your artwork to coated paper using a laser printer, then iron it to your part.  Soak the paper off.

Inkjet printer paper used to be a good option.  Back in the day, it was made by coating normal copier paper with a water soluble layer to keep the paper from sponging up the ink.  Now, the best I can find is the page of a glossy magazine that is all white.  The criteria is that you want the laser print to stick, but you're going to soak the paper in water to rub it off later.

You have to use a laser printer (or laser copier).  Laser "ink" is a finely ground thermoplastic.  Thermoplastic being a plastic designed to be melted several times.  An inkjet printer will not work, because after the image is on the paper, you're going to use a normal laundry iron to reheat the paper and "glue" it to the part. The ink will melt and stick the paper to the part.

Now soak it in water to dissolve the paper, and you have a perfect resist.  I've etched 6 point letters onto circuit boards with this method.


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## Shotgun (Jul 27, 2021)

A good etching solution for copper is muriatic acid and fresh hydrogen peroxide, mixed 1-to-1


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## francist (Jul 27, 2021)

Tomzo said:


> My family runs a nameplate manufacturing facility


We used to deal with a similar business here some years ago. We got our photo-etching done there as well as some nickel and gold plating. Very rarely I would be out at the plant to pick something up or just go along for the ride and have occasion to go into the solutions room. The chemical smell was almost unbearable and I’m pretty tolerant, and let’s just say not all the tanks were 100 percent liquid tight. I used to call the place “love canal”. I’m sure your family’s outfit is way less scary.


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## Tomzo (Jul 27, 2021)

francist said:


> We used to deal with a similar business here some years ago. We got our photo-etching done there as well as some nickel and gold plating. Very rarely I would be out at the plant to pick something up or just go along for the ride and have occasion to go into the solutions room. The chemical smell was almost unbearable and I’m pretty tolerant, and let’s just say not all the tanks were 100 percent liquid tight. I used to call the place “love canal”. I’m sure your family’s outfit is way less scary.


I would not go that far - next year will mark 100 years of Kennedy Name Plate Co and my grandfather used to publish an industry newsletter titled "Acid Fumes" back in the 30's.   The chemicals are quite nasty in every possible way.   As a kid we would wash our hands in MEK which you can't even buy now.   It was a fantastic degreaser though....


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## Shotgun (Jul 27, 2021)

Tomzo said:


> As a kid we would wash our hands in MEK which you can't even buy now.


FYI: https://www.aircraftspruce.com/catalog/cspages/polyfibermek.php?clickkey=5201


Now imagine being in a booth spraying a paint that is basically plastic or aluminum dust dissolved in MEK.


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## Tomzo (Jul 27, 2021)

I can not only imagine it, I nearly bathed in that stuff - among other nasty things.   Back in the 70's people were not quite as concerned about this stuff as they probably should have.   At least my dad wasn't.


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