Low Cost Etching.




Introduction: Low Cost Etching.

About: I'm an electronic engineering student. I don't usually have much spare time but I like to work on random projects to keep myself entertained. I hope you like them!

In this instructable you will learn how to etch low-res designs on aluminum/brass/copper... plates.


-HCl (For being common and cheap, also known as hydrochloric acid, it's commonly used as a heavy duty cleaner), in case you want to work with copper you can also use Ferric Chloride
-Vinyl adhesive (although other adhesives can be used, as long as they don't get eaten by the acid, the more sticky it is better will work)




-Protective goggles.
-Common sense.

Step 1:

To prepare the plate, sand it with a fine sandpaper (around 200-300) and then clean with water, this will remove all the residues and will reduce imperfections, try not to touch the surface with your hands (because the oil on them could make the vinyl unstick while it's being etched) and put the vinyl adhesive on the plate.

Next we want to put the printed image on the vinyl and tape it so it doesn't moves, with a pen follow the lines of the image to transfer them to the vinyl.

TIP: A pen will allow you to tell which zones have been already transferred to the adhesive.

Step 2:

Now take off the image, take some patience and with an exact-o-knife cut the adhesive, remember we want to remove the "black" zones that are going to be etched so be careful not to cut or detach other parts of the vinyl.

If you have a vinyl cutter, laser cutter or similar this project is perfect for you.

TIP: Aztec format (the one I used) is the tiniest one but you might have troubles with some readers.

Step 3:

When I's done put tape around the plate so the HCl doesn't eats aluminum from the base or the edges of the plate.

Place the plate over a wet rag, don't put it on marble, granite, concrete or similar surfaces because the HCl will eat them away.

Put on your gloves and goggles and try to avoid spills, proceed to pour the HCl in a small quantity, enough to cover the surface, and wait about 2-3 minutes, if you see the reaction goes too fast throw some drops of water, the plate might heat a bit so it's important to keep it cool (that's what the wet rag is for).

IMPORTANT: Keep the area well ventilated, use gloves and goggles for your own safety, the HCl goes easily into the air and can make your throat and your eyes itch, if you make contact with the HCl you will feel an itch and then a burning sensation, try to wash the affected area as fast as you can for some minutes.

General rules and common sense must be applied when working with corrosive substances.

Step 4:

When you think the etch is deep enough or the adhesive begins to peel off it's time to remove the HCl. Take into account the water heats in contact with the acid and that can cause a violent reaction, the correct thing to do is to pour the acid into a large amount of water, then grabbing the plate with pliers put it under the tap and remove the rest of the adhesive and the residues caused by the etching.

The volume of the solvent (in this case water) will be always larger than the volume of the acid to dilute, never try to dissolve large amounts of acid by pouring water into them.

When it is done place a sandpaper sheet over an horizontal surface and sand the plate so you end with a more defined etch.

Step 5:

The next step is to paint the etched zones, try to avoid dense oil base paints or wrinkles will appear when the paint dries, if you have to use some dilute it a bit.

Step 6:

Once the paint is dry sand the excess of paint by repeating the sanding operation on step four.

TIP: Put a bit of liquid soap inside the etch over the paint so the metal filings get stick to the soap and not to the paint, when you are done just wash it with water.

Polishing it's recommended, you can also use very fine sandpaper instead.

Now you know how to etch aluminum you can do all the etchings you want, from qr codes or identification plates to keychains and decorative objects.



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    41 Discussions

    Good idea! Three points I want to emphasize:

    1. ) Wash anything that comes in contact with the acid thoroughly
    2. ) Remember this acid eats anything organic -- Vinyl apron is a good idea
    3. ) Be VERY careful adding water to acid - it gets hot quick DO NOT pour acid down a drain and then run water.
    1 reply

    4. ) also always pour acid into water, never other way around.

    5. ) do not pour into a metal container.

    6. ) it will get hot when put in water.

    7. ) Very Important DO NOT pour down your drain!

    These basic guidelines jascanlan and I put down should help you out Victor.

    I tried to make the etching smaller with more definition to attach them to a small keychain but it's quite hard to do it with common materials, I tried wax, sellotape... all were dissolved by the HCl, I'll keep investigating.

    The nail polish seems a good option but it's hard to apply it in a precise way.

    About 3-5 minutes, I have to say I reduced the concentration of the HCl with some drops of water.

    I hope people realize just how uncomfortable it is to get muriatic acid on your skin. It burns like crazy and itches like crazy and soap and water only fix it a little. Talking from experience. And Victor, could you please recommend people to wear gloves?

    I know it is common sense, but you never know these days......

    And do this outside too.

    7 replies

    Ok, I'll edit it to add more security measures.

    Thanks to all the people who are posting important information about the acids and their dangers.

    Victor, can you also edit your hard work to reflect that if you do this outside to avoid inhaling the fumes you need to wear at LEAST SPF 40 sunblock so you don't get a sunburn? and also to get at least 8 hours of sleep a night, never swim right after eating, and not to play on or around dumpsters?
    Oh, one other thing- if you buy the HCl online, be sure to use SSL for the transaction so hackers don't steal your credit card information.

    I giggled, I did this with my bare hands near to a window, but I'm responsible for the acts I do and I've also done this (and worse things) a lot of times. If other people don't want to take the pertinent security measures I'm not going to yell at them, but I posted them (even if excessive) to let them know this can be kinda dangerous, and if they put in practice this measures there will be less probabilities they end hurting themselves.

    It's good that you've posted the relevant safety precautions. This strikes me as a fairly simple 'starter' project for working with corrosives. If I wanted to start having a go I might start with something like this (well, I do want to have a go but there isn't time in the world for me to try all of the cool stuff out there). So I imagine that there could be many people who haven't worked with HCl before.

    I like it. This part was funny


    -Protective goggles.
    -Common sense

    now you don't have to feel bad for all the "we have a be nice comment policy or else you know what I mean" in the world type people.

    As long as you can keep making instructables Victor; do whatever the heck you want!

    Yes, all very important. Not just SSL, a couple proxy servers as well. nah SPF 40 is not good enough for me. 60 with Aminobenzoic acid to block against UV -B's and Zinc oxide for your face and Avobenzone to block against UV-A's. It's okay to gently dip your body into water after eating, (at a rate of 1.5ft per 30 seconds) and you can only recreate around dumpsters, (never play), and buy that Human Computer Interface (HCI) from a reputable company.

    These are all things that WE THE PEOPLE call for for proper regulation and compliance with the Over Regulated States Of America.

    No you need hydrofluoric acid for etching glass

    Throw away the acid, use a salt, then with a battery and q-tip and some wires, do a electro-etch. If you get the polarity right, you can get up to 1 mm depth. If not, you get a plating effect. You also can paint the surface with nail polish. What get coated won't get etched.

    It's worth nothing that ordinary sharpies (permanent marker) work just fine for obscuring the places you don't want to etch, at least for using standard (ferric chloride) solutions with copper plates. You just have to watch the stuff a little more closely. For electronics it works best with relatively thick traces though (maybe 1/16 inch wide).

    Just a suggestion, as opposed to putting your HCL solution into water a better idea would be to make a supersaturated baking soda (NaHCO3) solution (add to water and mix, keep adding until no more will dissolve) and either add your entire HCL bath to that or just the plate. The NaHCO3 will neutralize the HCL, leaving you with water and NaCL (table salt). It is more immediate, so the ethcing will stop faster, and it is safer. Just some bubbles as opposed to a violent exothermic reaction.

    An important note: You should NEVER drop water into an acid!!!! This will cause the water to "boil" and splatter the acid. Be very careful, particularly if you are unsure of the molar concentration of the acid.