Etching Large Metal Items

Alright first ible, here we go. Used this for my second: https://www.instructables.com/id/Gorget-neck-armour-neck-armor/

Ok so small update, although I got voted up to 4th position the judges didn't find my ible good/relative enough to pass the first round:(, but I still want to thank everyone who voted for my ible!!

I wanted to etch an image onto my neckarmour(gorget) but i found no instructable on how to etch larger metal pieces, just a load on etching smaller pieces(mostly knives). Considering the size of this etching and the size of the metal, it would take too long to do by hand(the q-tip method) and too large to do with the submerged method, so i flipped the submerged method over and came up with this:

Step 1: Tools and Materials

A simple list of materials, if you dont have these items just improvise.

your metal piece
a piece of waste metal
an adaptor / 9v battery (i used a 12.5v adaptor)
few pieces of copper wire
bag of tealights / paraffin candles (i used about 10, it depends on the size of your design)
nailpolish (doesnt matter what colour, wouldn't go for metal colour :P)
nailpolish remover / acetone
exacto knife / hobby knife
lighter
vinegar
salt
lots of tissues

*optional items*
q-tips
A4 sticker paper
pen / pencil
fan
bowl

Step 2: Preparation and Nailpolish

Ok so you got your large metal piece ready to etch, lets begin.
First find or create a nice design you want to put on your piece. print and cut it out with about 0.5cm to spare on the edges.
Second you will need to clean the metal with some degreaser.
Third apply a thick coat of nailpolish the size of your design and add about 2 inches / 5cm to all sides.
now lets just wait till it dries and watch some lego starwars:P

Step 3: Design

Now put on your design either by drawing it onto the nailpolish, or glue on your printed design (I used sticker A4 paper). Trace your design with a hobby / exacto knife, thus carving into the nailpolish. Go slow and steady with this, dont push too hard. if you screw up you can fix it with some nailpolish, but if you scratch the metal its probably permanent.

this step takes really long so put on a series or something and take your time to prevent screwups!!

Step 4: Clearing Your Design

Ok so now you're done with tracing your design(or partially if your impatient like me) so lets start the next step.
first start out by removing all of your design paper / sticker (unless you drew yours) and widen and deepen you traced design.
Next cut out all the parts that need to be etched down. make sure that ALL the nailpolish is removed from the surface that is to be etched down or you might end up with bumps in the middle of your design.

Step 5: Cutting the Candles

Finally! you're done with cleaning up your design after hours of carving nailpolish....
Now cut your tealights / candles in half and place them around your design untill it's completely surrounded. Cut some more in 4 pieces to put on top / in between the halves to fill up the holes.

Step 6: Candle Dam

When you have enough candles cut, you can start building a candle dam. This is why this instructable is different from the rest;). 

Start out by slightly melting the flat side of the candle halve and stick them around your design, make sure that the candles are on top of the nailpolish edge around your design so there is no metal(except the carved design) exposed within you candle dam.

Have 1 or 2 candles lit nearby so you can pour on some molten wax to seal the edges and secure the halves.
Next place the quarter candles in the gaps between the halves and secure with more molten wax. keep this going till you have a dam all around your design. make sure there are no gaps and no metal exposed that is not part of the design, use some more wax if needed.

Be sure to keep your design clear of any molten wax.

This method can be used (as shown in this ible) on curved surfaces as well. 

Simple and short step, walk over to the sink and fill with water to check for leaks. if there are any leaks dry it off and seal with more molten wax.

Step 7: Etching

Ok so now we are ready to etch. DO THIS IN A WELL VENTILATED AREA!!! during this process harmfull gasses are produced like chlorine gas. Its common sense to do a test piece first to check how long you need to keep the current connected.

Using a battery is not recommended for large pieces because it will probably take a few batteries.Connect a piece of wire to the positive (+) side of your battery / adaptor and to the metal. the best place to connect your wire to the metal is on the underside in the middle of your design.

Now take your scrap piece of metal and connect a wire for your negative (-) to this piece. 

Mix your vinegar and salt (in a bowl) and place your project on a stable and level surface. fill your candle dam with the vinegar and salt mixture. Take a q-tip and rub in the solution into all the fine lines to make sure there are no airpockets.

Place the scrap piece of metal (with the negative connected) in the solution in such a way that the two metal pieces dont touch. When everything is secure and safe plug in the adaptor / connect the battery and leave so you dont inhale any gas.

now its waiting time, it takes a while (mine took about a half hour) for the metal to get etched. 

I don't know if it helps but i think it does, if you take a q-tip and every 10 minutes or so just wipe the design clean to get the oxide and bubbles off.

Step 8: Cleaning and Reveal

After the excruciating wait (you should have done a test to check how long it needed) the time has come to clean and reveal you masterpiece. start of by dumping your vinegar / salt solution and breaking off the candle dam. 

Wash off any vinegar and candle wax left in the sink.

Now its finally time to reveal your hard work! take some nail polish remover / acetone, put some on a tissue and start removing the nailpolish.

Stop and admire your work once in a while.

Once fully cleaned grab yourself a beer and ride into battle looking sharp;)

Cheers!

Comments

[strangestuff93]

Nice work like the reverse aspect of the etchin. i used to do the electro etch on stainless cups. After doing 60+ i found it easier and faster to sand blast the design on metal. I also use vinyl for the stencil. I cut it on a silhouette. Its easier if your doing multiple copies.

[knutknackebröd]

thanks for your comment, if you are doing production work it would be a lot easier to use sandblasting or invest in a proper large etching bath, but for one or two pieces etching like this works fine.

[nramirez10]

one thing im confused about is the scrap metal you hook up the negative to do you dip it in the same pool of mix as the piece you are etching?

[knutknackebröd]

Yes, by allowing both metal pieces to touch the solution (pool of mix) but not each other, the current will strip off some of the metal and transfer it to the scrap piece. It is simply electroplating in reverse, https://en.wikipedia.org/wiki/Electroplating

Thanks for the comment,

Cheers, Knut.

[graymachine]

Additionally, if you are using the battery method you can get multiple batteries, hook them up in a series or parallel to increase the voltage or amperage respectfully, and etch much quicker. I tried it both ways and didn't see any particular advantage in one over the other, but it certainly was quicker than a single battery. I recently did a battery etch with 4 9V batteries hooked up in parallel and was pleased with both the speed and efficiency given the size. I would also recommend using a pair of plier and a cotton ball rather than a Q-Tip and alligator clips as the coverage is much better. That said, you need to be very careful hooking up batteries in a series or parallel; not only could you easily short your batteries by being clumsy, this is also wandering into voltages that are dangerous (assuming I did that 4 9V battery setup in a series that would be effectively a 36V battery). If you are going to be etching more than occasionally it is probably worth it to simply buy a portable jump starter/battery charger since you can set the voltage and amperage, not to mention that it doesn't run out of power like the batteries.

[knutknackebröd]

the main reasons i opted for a transformer rather than batteries is that batteries tend to run out quite quickly when doing larger pieces and have a tendency to explode / leak if messed with too much.

[graymachine]

Wouldn't it be simpler to create a border around the area to be etched with putt, cut the bottom off of a sufficiently large disposable tupperware, and push it into the putty to make a watertight seal?

[knutknackebröd]

As mentioned in a previous comment, the main reason why I used this method rather than clay / putty is simply that I made due with the stuff I had lying around. Using a disposable container to lower the amount of clay needed is a nifty idea.

thanks for the comment.

cheers, knut

[christopher cramer]

I attempted the q tip method on a rather large piece of metal but the etch was far too shallow. All I did to make a stencil was carve it into a sheet of vinyl. Would the vinyl be enough to resist the electric current and the etching solution if I used this method.

[knutknackebröd]

Honestly I dont know, I've never worked with vinyl. However, all the stencil needs to do is keep the water / acid from reaching the metal, Try out a small test piece with some vinyl scraps and you'll know;) cheers, knut

[incensedpanther]

Very cool. I've wanted to etch for a while, but I thought it had to be all that dangerous acid stuff. thanks I've got some stuff to do....

[knutknackebröd]

Do keep in mind this does produce some nasty stuff of its own, so keep it well ventilated.

[Chris_Dugdale]

For etching steel, try using ferrous sulphate (iron (II) sulphate) or ammonium ferrous sulphate solutions, instead of salt and vinegar. For copper and brass, use copper sulphate. for zinc, use zinc sulphate.

There are several benefits...

1) No chlorine gas (which is nasty stuff)

2) No gas of any kind, so you don't get bubbles preventing your electrolyte solution from making contact with your piece.

3) The electrolyte solution doesn't turn caustic with use.

4) The solution doesn't get used up, so you can use it over and over again. You etch the cathode, plate the anode and the solution remains intact - it's just a carrier for the metal ions, as long as the metal matches the sulphate (copper for copper, iron for iron, zinc for zinc).

5) Using salt (NaCl), you can produce some pretty nasty by-product salts (ferric chloride, chromium chloride); matching metal to sulphate limits the productions of these toxic salts. You also don't get any way near as much precipitate (sludge) from using sulphates over salt.

[knutknackebröd]

The whole point was to do this with stuff I had lying around. As for the nasty byproducts, do the etching outside to prevent any gas buildup and on the small scale the production of the other nasty stuff is negligible.

[larroyo1961]

How deep does it etch?

[knutknackebröd]

depends on how long you leave it running, make sure to try a test piece!

[larroyo1961]

you say to use an adaptor but the adapter only has one cable for power where is the negative connected to?

[knutknackebröd]

as stated in the ible, connect the positive to the etch piece and the negative to a scrap piece

[JasmineandViolets]

Thanks for this, I had no idea you could use vinegar and salt. I usually use distilled water then mix in salt until it can no longer dissolve.

Beautiful etching.

[knutknackebröd]

thank you, and yes you can use water but the acidity in vinegar helps a bit.