How to etch aluminum panel labels/designs with a reusable acid mix

This tutorial will show you how to etch your own designs/labels into aluminum panels with a reusable acid mix instead of using electricity(the most common method).

It's a pretty good and cheaper alternative to profesional made panels for your home made synths, stomp boxes, etc. :)

As with any work involving dangerous materials, you'll have to be very careful and take any precautions needed if you are going to try this instructable.

If in doubt, don't do it!, and if you do it anyway and get hurt, don't blame me or this website, you have been warned ;)

WARNNG NOTES:

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Acid can burn holes into your skin, wear some protective clothing, gloves, eye protection and gas mask with the appropriate filter designed for acids before handling it!

When the acid mix reacts with the aluminum it starts to produce acid vapours that of course are dangerous to your nose and lungs so by any means, DON'T breath that!

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If you feel like this is too much for you to handle, you are probably right and is time to stop reading this and look some place else, otherwise let's move on:

Step 1 Materials

List of materials:

-Some aluminum panel/s

-A nice design for the etching

-Laser printer w/ black ink

-Some pnp-blue sheets

-Gloves

-Eye protection glasses

-Protective clothing

-Hydrochloric acid (same thing as as muriatic acid)

-Hydrogen peroxide (same thing as oxygenated water)

-A shallow plastic container to mix the peroxide with the acid (2:1 mix, depending on the peroxide concentration you may need to change the mix, I used 11vol. peroxide)

- Another container with water to rinse the panel.

-***Extremely well vented work area*** try this only if you have access to any open and well vented area, the process creates some probably dangerous, and bad smelling fumes, beware!!!
-running water(avoid any metal tool/surface... metal kitchen sink is a no-no, unless you like to spend some $ on repairs )

Comments

[siamonsez]

Did you do anything to protect the bare metal after the whole etching process is done?

[sineSurfer]

Hi siamonsez, not really as I like the matte look, but fingerprints show up right away. You can try with clear lacquer spray, or maybe aluminum anodizing, check this link:

http://www.thefintels.com/aer/homealuminumanodizing.htm

[lumpee]

ehmbee,you might try "ring the doorbell,the dog needs the exercise"

[Alcyon]

Hl=ello,
Does anyone know if you could do the etching with natrium hydroxide (cautic soda) ?

[ryukyu]

I commonly do etching on PCBs which has the outcome of useable traces. What is the benefit or etching the metal to paint it? Is it simply to protect the paint itself?

[sineSurfer]

Hi ryukyu, "Is it simply to protect the paint itself?" sort of...

In this case, at least for me the final retro/industrial look matters too, have you seen a really old power tool or elevator? I bet they have lettering made using similar methods.

But yes, it does protect the paint from getting stripped from the panel, but you can do it if you are willing to :)

The point is... unless you have the proper stuff and supplies for screen printing which is how most of modern panel labeling is made nowadays, this is a quick and cheap alternative to create your own lasting labels and designs in anything made of metal.

[msw100]

Cannot buy Hydrochloric acid in the UK will anything else work ?

[sineSurfer]

Hi, I really don't know about a direct substitute for the Hydrochloric acid, have you tried asking for "muriatic acid" at a hardware store? that's where I get it locally.

Other option would be going with the original pcb etching method (ferric acid) look around here in the website, but ferric acid is too aggressive with aluminum, eats away the alu really fast so is not easy to control and most probably you will end with a faded etch, bot worth trying if you like a dirt/old/used/damaged look hehee.

Or go with electrolysis, see jeff-o comment.

Good luck!

[josh1324]

Is that for an atari punk console? Because I made one about a year ago, it was my first actual electronic project.

[sineSurfer]

hi josh1234, yes it is, great little project and now in a diy wood case :)

[josh1324]

thats awesome! Lol I have mine in a peoples jewelery case.

[josh1324]

btw, I later changed the shity speaker to just a male audio jack.

[trueblackdragon]

Danger! most aluminum etchants produce hydrogen in copious amounts! so no smoking or open flames please!!!

Remember the Hindenberg folks!

[lazemaple]

I have 3% peroxide which is sold in drug stores and 35% peroxide which I think may be too concentrated? Also, do you add the peroxide to the acid or the acid to the peroxide?

[sineSurfer]

Hi lazemaple: I'd go with 35% peroxide as it should work faster, giving more oxygen to the mix to work with... maybe you want to try with a scrap alu piece first to test the etching speed And you must add acid to the peroxide, never the other way, the explanation: A large amount of heat is released when strong acids are mixed with water. Adding more acid releases more heat. If you add water to acid, you form an extremely concentrated solution of acid initially. So much heat is released that the solution may boil very violently, splashing concentrated acid out of the container! If you add acid to water, the solution that forms is very dilute and the small amount of heat released is not enough to vaporize and spatter it. So Always Add Acid to water, and never the reverse. extracted from here: http://antoine.frostburg.edu/chem/senese/101/safety/faq/always-add-acid.shtml

[fudg]

you could always use asphaltum instead of the pnp-blue sheets. this way you can actually etch a hand drawn image if you wanted to. also, it would be easier to cover up mistakes with asphaltum if the pnp-blue sheets didn't work properly.

[smokehill]

Haven't heard of this stuff for years -- is it still available somewhere? Some time back I was trying to research how some early Marine Corps dogtags had the thumbprint etched on the back. My Dad's was the only one I had ever seen, from 1941. Eventually I found out that the USMC did this by painting asphaltum on the back, pushing the thumb into it, and giving it a quick acid bath. Apparently right after Pearl Harbor they cut out that step in the dogtag process to move men thru quicker, and never went back. I assumed it was some sort of petroleum product but had never run across it before (or since).

[smokehill]

I've done a bit more research on the old acid-etched Marine dog tags.  It seems there was another intermediate step I wasn't aware of.

Actually, it was the right index finger (not thumb) that was used,  and it was rolled onto the asphaltum mix on the back of the dog tag, much like any fingerprint is taken.  However, before the tag got the acid bath it was "fixed" by heating it over an open flame, apparently cooking the print into a hardened coating.

Only then was it dipped in a (basically nitric acid) mix to etch the print into the metal. Usually the dip time varied, between 30 - 60 minutes.  The whole process can be Googled up without much difficulty, using "marine acid dog tag" or something similar.  The old Navy instructions are in several places.

[shamanwhitewolf]

A quick Google and I found some here: http://www.dickblick.com/products/asphaltum-liquid/#description I don't know this company, I'm just pointing to one possible source.

Apparently, asphaltum is also referred to as bitumen, though other reading seems to give differing definitions of the two.

I like your idea of using asphaltum (or possibly several other inexpensive paint-on products). You could print and cut out you pattern on regular paper, then use that as your painting guide.

[sineSurfer]

If you aim at more artsy stuff, you could use colored wax too, cover the whole panel with wax, remove the parts you want etched with a needle or something like that. Easy to get( any candle will do) and resists the acid bath fine, but forget about precise drawings :)

[exlxaxd]

One thing I don't understand: What's the purpose of printing on regular paper and taping the PNP to it? Can't you just print the design directly to the PNP Blue sheet without the pre-printing and taping? Great instructable, by the way.

[sineSurfer]

 Hi, is just to save on the pnp sheet, so you can see where the final print will be and use only enough pnp for the job,  no point on wasting it,  of course you can print just a small square or marks as a guide  and then stick the pnp to the paper ;)

[airfoil]

would a photocopy machine work the same on pnp paper instead of a laser printer?

[flyingpumpkin]

www.techniks.com/information.htm
According to the PNP website you can use a laser printer or photocopier (as long as it uses dry toner which is most of them).  You cannot use an inkjet.

"An image is printed or photocopied onto this film, using a laser printer or photocopier (dry toner based), and subsequently ironed or pressed onto a cleaned copper clad board. "

 

[sineSurfer]

It should work, just be sure to use a photocopier with high quality setting, you want enough toner on the pnp to make the transfer easier ;)

[dr.Maligno]

hi from spain, did you used peroxide vol.11 or vol.110??
thanks

[sineSurfer]

 hola dr. Maligno!, I used vol. 11 as that's all I can get over here, a friend from Tenerife uses vol. 30 for pcb etching, he gets the pcb's etched in 25 seconds! you may want to try with 30 too :)

I'd do some tests on spare aluminum to see how fast the etching goes, as it can be to agressive and ruin your design.

[dr.Maligno]

after doing some prove expreiments, i did try vol.10,vol25 and 30, but its too slow process. At last, i buy peroxide 110.vol and then the pedal become etched.

[sineSurfer]

 that's weird, but good to know it worked at last, post a picture when your pedal gets finished ;)

[dr.Maligno]

last day i upload some photo but i dont know wath happend and finally not load. sending photo......

[elabz]

Guys, I'm missing the important bit of info: what's a "pnp blue"? Is it a transfer paper of sorts?

[ColorfulNumbers]

That refers to "Press-N-Peel Blue," a product for transferring a resist onto metal. It's used for making circuit boards

It comes in sheets. You print your design onto the Press-N-Peel using a laser printer or copier (but not an inkjet), then transfer your pattern from the Press-N-Peel to the metal using a clothes iron. If you place the metal into acid, any surface not covered by the resist gets etched away, but the protected metal remains.

Details on the manufacturer's website here.

[dchall8]

Thanks to scriptster for asking about PNP and thanks to ColorfulNumbers for the reply. PNP stands for lots of different things. I had no idea this stuff was around. I wonder if the PNP will work to make a resist on fabrics?

[ckolios]

It would be great if someone did a video of the whole process

[tiltmonkey]

Am I right in thinking that for a small area I could just use the indelible ink through a stencil? This is just what I've been looking for to decorate harmonica coverplates.

[vidakk]

It should work. I have done countless PCB prototypes by drawing traces with waterproof pen on copper, and then etching.

[sineSurfer]

Don't know if the acid will go thru chrome finish(my harmonica comes with it), if yours too, I'd run a test on something else first. And remember the indelible ink will get eaten by the acid too if left for too long, just check often ;)

[Blacksmith Spader]

will this work with steel and iron as well?

[sineSurfer]

yes it should work, and for that matter on any bare metal surface, not sure about etching times though.

[=SMART=]

Yay atari