How to Etch Aluminum Panel Labels/designs With a Reusable Acid Mix




Posted in WorkshopMetalworking

Introduction: 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 ;)


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!

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


-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 )

Step 2: Print on Pnp Blue

1.- Create your design in any vector app: Illustrator, Corel Draw, Ink Scape, etc.

2.- Flip the design before printing as you would with pcb etching.

3.- Print the design on regular paper sheet(100% scale), this will work as a guide to print on the pnp sheet.

5.- Cut a piece of pnp-blue just big enough to extend a little bit from the edges of your design on the already printed paper sheet, the extra length will help to print and transfer the design to the aluminum panel.

6.- stick the pnp blue to the printed paper sheet with some tape on each corner, use just enough tape to hold the pnp in place.

7.- Set the laser printer to high quality print, again, 100% scale.

8.- Print again, you should end with something like in the image below.

Step 3: Preparing the Aluminum Panel

Now that the pnp blue is ready to transfer, we need to prepare the aluminum panel, so:

1.- Cut the aluminum panel to the desired length.
2.- Use water sand paper to smooth out and remove any dirt/grease from the panel surface.
3.- Clean the panel with running water and dry with paper towels.

Step 4: Transfer the Design to the Panel

Now we are going to transfer the design from the pnp-blue to the panel, same method as with the pcb toner transfer:

1.- Place the panel on some scratch piece of wood.

2.- Place the pnp-blue over the panel, make sure it's well aligned.

4.- Use tape to hold the pnp-blue on each side, make sure there are no air bubbles, wrinkles or deformations and the pnp-blue lies flat against the panel.

5.- Place some piece of cloth over the panel to protect the pnp-blue from the heat.

6.-Use an Iron to heat the toner on the pnp-blue, trying to cover everywhere, after a few minutes the toner will start to look darker, check from time to time to find any missing spots.

7.- When the toner looks black everywhere, the transfer is ready.

8.- Wait for the panel to cold down, then remove the tape, leave the pnp-blue in there.

9.- Now remove the pnp-blue, there may be some spots where the toner didn't transfer to the panel, we will fix that on the next step.

Step 5: Fix the Missing Spots

As you can see on the image, there are some missing spots, we are going to fix those now:

1.- Take a sharpie pen(or any other indelible ink pen) and paint over the missing spots, retouch any spot 2 or 3 times to allow the ink to cover the spots and resist well the acid.

2.- Use tape to cover big areas/borders, etc.

3.- Picture #3 shows my panel, almost ready to etch.

4.- As you can see on image #4, I used the pnp-blue plastic left over to cover the back of the panel, this is important, you have to cover every part of the panel not going to be etched to prevent the acid from damaging the panel.

note: If the transfer ends up with a lot of missing spots or missaligned, you can clean the panel and start all over again, sometimes is better than fixing any mistakes.

Step 6: Etching the Panel


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!

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:

1.- Go to a very well vented area, put on your protective clothing, gloves, eye protection and gas mask with the appropriate filter designed for acids before manipulating the acid, remember, don't do it indoors!.

2.- Use the shallow plastic container to mix the peroxide and acid in a 2:1 proportion, mix just enough to cover the panel and remember, ADD the hydrogen peroxide FIRST, then pour the acid slowly, to avoid any acid splashes.

3.- Place the panel into the container.

4.- The mix will start to react with the aluminum producing a lot of tiny bubbles, and acid vapours, DON'T breath that! , the acid will start to eat the unprotected parts of the panel.

5.- You can take out the panel and rinse it with water(another container with water will do) to check how is it going, take it back to the acid container if it needs some more time.

6.- Let it work until the groove depth left by the acid is about 0.5 mm, you can feel it touching the panel, or taking a closer look, remember to rinse the panel before any inspection, if you let it for too long, the acid will start to corrode the toner and damaging the protected areas.

7.- When the panel is ready, rinse it thoroughly with running water, remove all the tape and rinse it again.

8.- Here comes the green part, after the panel is etched, save the acid mix in a plastic bottle to reuse it another day, it will keep the strength to etch more panels.

Step 7: Painting the Panel

Now let's paint the grooves left by the acid:

1.- As you can see I didn't removed the toner, we'll do that later, prepare some space to be able to spray paint the panel, any automotive paint will work.

***note: you can remove the toner before painting the panel if you want, just use some old cloth or towel paper with nail paint remover (acetone) or thiner... but I'd say it's an extra step not really needed as you probably want to give the panel a smoother finish later with the wet sand paper, it will remove the toner too, but is up to you :)

2.- Cover every part of the panel doing several small passes, paint, let dry, paint, let dry, etc. so the paint sticks better.

3.- You should end with something like in the picture #2.

Step 8: Finishing the Panel

Let's finish the panel:

1.- After the paint dries, use a water sand paper with a fine grit to remove the excess paint and the toner from the panel taking care to not over doing it on the recessed parts so the paint stays there.

2.- Rinse and dry the panel and that's it for panel etching.

On picture #2 you see how the panel will look with knobs.

btw. I'd like to thank a friend, without him telling me about his experiences with the magic mix(muriatic acid+ oxigenated water) and diy PCBs I would not come up with this variation on the theme, thanks simone, aka cimo :)



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Just want to re-emphasize the point that you add the acid to the hydrogen peroxide, not the other way around. In chemistry we learned it as AAA - Always Add Acid. You never pour the acid and then add stuff to it. For example, if you have concentrated HCl and add water (or hydrogen peroxide, which is mostly water), the first few drops of water will immediately boil and splatter, splattering acid. If you add the acid to the water, the water will warm up, but because there's so much water than acid, it won't boil. Very important safety tip!

Also, for people who can't find Hydrochloric Acid, look for Muriatic Acid. Same thing.

aluminium concentration in etching process

Great, but why would you need the hydrogen peroxide? It's aluminium after all.

1 reply

It gives extra oxygen to the mix and makes the chemical reaction faster ;)

Hi there, anyone knows how that solition work in terms of recycling rese mg concern is that I dont wont to be harmful for the environment, I use this solution for PCB but in that case you can reuse that for yeas and there are even easy way to filter the copper back if you want to dispose the solution. Maybe I should look at electrolysis?

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

3 replies

Stands for "Press'n Peel". Many people like glossy photo paper better. Here's a link to a good tutorial using Staples' brand.

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.

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?

I Googled "pnp blue" and it came back press 'n peel blue. After chasing a link to a forum that had a failed link, I found this on the author's own website listed in his profile:

This is a procedure for etching printed circuit boards using Staples glossy photo print paper in place of PNP.


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.

6 replies

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).

Thank you smokehill for that information. My grandfather's dog tags also have his fingerprint. When I describe them to other people, I received the "this guy is full of crap" look. You just solved one of the mysteries of my life.

Try the greasy smoke of a candle kept close to the plate, Wax will condensate against the plate surface and I think it may work in protecting metal from acid. But now I say why not try melt candle wax itself .
Anyway for home made asphalt try direcct hot boiling in some tuna can resin from any kind of pine tree. Stop boiling when it turns dark and thicker. A very interesting kind of free home made stuff mentioned in Noa's ark materials and then after.

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.

A quick Google and I found some here: 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.

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 :)

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

1 reply

Yes, if it is dilute.