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Acid Etching Brass Plaques

Hello and welcome back to Switch & Lever!

Regardless if you're trying to unplug your drain, or dispose of a body, acids are awesome

things!

Today we're taking a look at how to create something a bit more interesting, how to make

brass plaques using a comparably weak acid, Ferric Chloride, and brass plate.

Etched brass plaques used to be standard on many kinds of electronic devices and machines

in the past, and regardless if you're restoring an old device with destroyed plaques, or making

something new and using them for decorative purposes, they can truly make any project

pop.

Now, before we start off, remember that acids are corrosive, so regardless what you may

see me do in the video, it's your responsibility to use proper safety gear.

At the very least, use gloves, glasses and clothing you do not care about when handling

acids.

Optionally, kiss your spouse goodbye and tell your children you love them.

The very first thing we have to do, before heading down into the workshop, is to actually

design our plaque.

This could be made entirely from scratch, or if you're restoring something old, based

on an original plaque.

You can of course use any number of software to create the graphics, but the important

idea is that you're only making it black and white, no color, and no grayscale.

This graphic will be used to create a resist, where the acid will be prevented from etching

away the brass.

We are going to explore a few different methods to see which way may be the best to make this

resist, and which provides the best results.

First things first though, start by preparing your brass plate.

All three methods we will explore require the same pre-treatment.

Cut your plate to size, leaving a good margin around the final design.

Clean off all oxidation and crud from the surface of your brass using a fine sandpaper

or scotchbrite, and finally clean the brass thoroughly using a solvent like ethanol or

acetone.

Be careful not to touch the bare surface with your fingers once clean, as skin grease will

prevent the acid from working properly.

The first method is a way that has been documented well before online, the transfer of laser

printer toner onto glossy paper.

Start with taking the design you want to etch, inverting the colors and mirroring the design,

for reasons which will become apparent later.

Find a magazine with really glossy paper, or special photo paper for inkjet printers

work well as well.

Feeding magazine paper alone through a laser printer may cause a terrible jam, so it may

be a good idea to tape the paper down to a thicker backer paper, to ensure that it makes

it through the printer in one piece.

If your printer has settings to print in deeper black than regular, choose that option, as

we want to put as thick of a layer of black toner onto the paper as possible.

This toner will act as our acid resist.

Cut out your design and take the brass plate you prepared before.

Take your design, flip it upside down and tape the edges down onto your brass.

We will essentially melt the toner onto the brass using heat.

You can do this with a clothes iron, but I've found I get far more consistent results using

a desktop laminator.

However, if you care about your laminator, it's a good idea to make a small paper sleeve

for your plaque, so you don't mess up the laminator.

Make sure the laminator is set as hot as it will go, and continue to feed the plaque through

the laminator 5-10 times, to ensure enough heat is transferred into the brass, and that

the toner will stick down properly.

Of course, we still have the paper stuck to the toner as well, so let's get working on

removing the paper from your plaque next.

This could really not be easier though, just stick it under a tap of hot water and allow

the water to soak through the paper.

Rub the back of the paper with your fingers rolling off the paper piece by piece.

It may take a little time to get all off, but patience and gentle handling will reward

you with a good result.

Don't scratch it, as you may damage the toner which remains, just work slowly and carefully

until the areas where there is no toner, i.e. your design, are exposed clearly.

There are commercial versions of this method as well, where you print on a transparency

and use UV light to cure the resist onto the brass, but as far as DIY methods go this is

probably the easiest.

Second method is though even a bit easier, but it does require some specialized machinery.

Take your prepared brass as before, and simply paint a couple of layers of regular black

spray paint on top.

Once dry, lay it into a laser cutter and etch away the paint from the brass in the design

of your plaque.

The laser won't affect the brass at all, we're only removing the paint in this step, to create

something similar to the result from the last method.

Third method is actually not that different, and more of an experiment.

We're using a product from CerMark, which is a laser marking spray, which allows you

to essentially mark metal by burning paint onto its surface.

This is a semi-permanent mark, and in my experience only removable by sanding it off.

Spray-paint your brass like before, and once the paint has dried laser your design onto

the paint, and as before make the black areas where you don't want the etching to happen.

Once it's done, you can simply wash off the leftover paint with warm water.

Now we have our three plaques ready for etching.

Right now there is not much difference between them, aside from the black spray paint one

looking perhaps a bit thicker than the other two.

To be able to make any sort of etching on the brass we do need our acid.

In some places you may be able to find pre-mixed ferric chloride being sold as a circuit board

etchant.

The methods described in this video will also work great using that, but you may only be

able to get hold of it in dry form, meaning you need to mix it yourself.

Follow the instructions on how to mix the ferric chloride with water to achieve proper

concentration.

Be aware though that it is a very exothermic reaction, so it will produce a lot of heat.

Therefore add your ferric chloride powder slowly, and allow the solution to cool down

properly between each new addition.

Also, don't use metal tools or containers to mix the solution with, as it will start

etching the tools.

Once the solution is ready, make sure you label your container appropriately, especially

so if you're working in a shared space.

Even though ferric chloride is a reasonably weak acid, it's still not something you want

to interact with unknowingly.

The one thing left to do before we get to etching is to block out the rest of our plates

with packaging tape, to prevent any etchant going anywhere we do not want to etch.

The only place you want exposed is the design you want to etch.

As I want to float my plates in the etchant, to help the removed material to fall out rather

than accumulate in the etched areas, I taped the plates onto a piece of closed cell foam,

which will help everything float slightly below the surface of the ferric chloride.

In case there are some places on your designs which didn't come out quite properly, or got

damaged during the process, you can make some touch ups using a Sharpie before you start

etching, as the Sharpie ink will work as an excellent resist as well.

In fact, you could draw a design only with Sharpie and it would work just as well.

Finally the moment we have been waiting for, let's let the brass meet the acid, and make

magic!

I poured out my ferric chloride in a wider plastic box, to have space for all three of

my plaques.

I also started by brushing some ferric chloride on the plaque being etched, to make sure the

acid contacts all parts which will be etched, and removes the chance for air bubbles which

will prevent the etchant from doing its job.

Place the plaques down into the etchant, floating happily on the surface, and transfer your

plastic box somewhere warm.

While the etching process will work in room temperature, it will speed up considerably

if put on top of a radiator, or even in a tray of hot water.

Come back and check in regular intervals to see how deep the etching is going.

Depending on the strength of your acid, the warmth, how much brass needs to be removed,

and other factors, your time may vary dramatically from mine.

In total I think I left it in about half an hour, coming back every ten minutes to check

and brush the design lightly with new acid, removing any brass which was etched away and

didn't drop off naturally.

As you may see one of our plaques failed etching entirely, with the resist coming off while

etching.

So it's likely that the etchant was able to attack that particular resist.

We will look closer at the results later, and see exactly what happened.

Our acid, the ferric chloride, or more aptly named, iron (III) chloride, is actually etching

our brass in two steps.

It's reacting with the copper in our brass to first form iron (II) chloride and copper

(I) chloride.

The copper (I) chloride further reacts with remaining iron (III) chloride to form more

iron (II) chloride and copper (II) chloride, which is readily soluble in water.

The reaction is controlled by the resist we applied, as ideally the acid we use should

not react chemically with the resist, and only etch our base brass metal.

Once the etching is deep enough to your liking, take it out of the acid, and transfer it to

an empty plastic box.

You do not want to clean and rinse the remaining acid down the drain, so make sure you collect

all water you use for cleaning.

The issue isn't really that it's an acid we would be rinsing down, but rather that it

holds copper in solution, which is a water pollutant.

We will, however, deal with the remaining copper later, so for now make sure all liquid

is collected.

The old ferric chloride can be reused, even though it has now lost some strength.

Pour it back into your old container, and keep in a cool and dry place until you want

to use it next.

As there is still acid on our plaques we need to stop it from reacting further.

The easiest way is to use a base, something alkaline, to counteract the acidity of the

ferric chloride.

Common household baking soda is by far the easiest, and sprinkling it on your plaques

will cause a fizzy reaction as long as there is acid left.

Once the reaction stops, rinse off the baking soda into your plastic container, and remove

the remaining tape from the brass.

Also add baking soda to the rinsed off water to counteract the acidity within.

Before wrapping up your business at the sink, take your plastic container and put it in

a sunny window, away from the reach of pets, children or curious coworkers, and we will

get back to it at the end of the video.

As we can see two of our three plates etched as expected, with the third, our laser marking

paint, failing spectacularly.

The resist seems to have worked for a short while, until the acid ate it away and started

etching the entire surface of the plaque.

So, at least, we can chalk that up as a failure and move on with cleaning up the remaining

two plaques.

Using a solvent like acetone, or fine grit sand paper, remove the remaining resist to

get a clearer view of your etched design.

If everything went well you should have a clear and deep etching on your brass, ready

to move onto the next step.

The reason we etched the circumference of the plaque is to get a good guide to follow

when shaping the brass.

Break out your saws and files and embody our favorite Australian horologist 'G'day Chris

here and welcome back to...Switch & Lever?"

If you need mounting holes it's also a good idea to add a small dot in their center in

the design you're etching, so you get a good starter, kind of like a center punch, of where

to drill the holes.

The plaques look great, but really need something a little more to pop.

The etched areas should be filled with paint, and you can choose any color you really want.

Before painting do a proper prep, by degreasing the plaques as well as you can, using acetone

or paint thinner.

I'm going with a classic black on these plaques, but as you can see in a recent previous video

I also made a plaque for my desk fan using a red background, to really make the brass

pop.

You can use regular spray paint, or like I'm using here a hobby enamel paint, which will

hold up really well over time.

Don't worry about applying paint perfectly in the etching, just make sure it goes down

entirely into the recesses.

While the paint is still wet you can remove most of the overflow using an improvised squeegee,

like a piece of plastic with a sharp edge on it.

Leave the paint to dry thoroughly until moving on to the next step.

Using a fine grit sandpaper you can easily clean up the remaining overflowed paint, and

give the brass plaque its final brushed appearance.

If you want more of a polished plaque, there is nothing stopping you using higher and higher

grit sand paper and polishing compounds until the plaque shines like the sun.

You can also varnish the plaque when done, if you want to prevent it from tarnishing.

Personally, I like it brushed, and I like tarnished brass, so I'm leaving it as is.

The finished plaques are quite similar, but there is one important difference, which we

also touched upon before.

The plaque used by the paper and ink transfer method is closest to our intended design,

with the plaque made by lasering away spray paint has a bolder look, either like the laser

ate away too much paint, or the etchant started to lift the edges of the paint and crept under

it.

The results may also be different using another kind of paint.

Either way, they're both functional methods, and look almost as good.

Now go and screw or rivet your plaque onto your final project, like an old lathe getting

a workover, or like I'm doing, sprucing up an old project with a fancy new plaque.

Back to the final point of the video.

Remember the copper contaminated water we put in the window.

If you have the patience, simply leave the container in the window until all water evaporates

and leaves only the solids at the bottom of the container.

If you don't have the patience you can boil off the water in a glass container as well,

don't use metal in case of remaining acid.

Once everything is dried up the copper is no longer in solution, it's a solid and holds

no danger to contaminate ground water, and can therefore be safely discarded in a regular

trashbin.

I hope you enjoyed this video.

While you're waiting for your plaques to finish etching, why don't you check out one of the

many other videos from Switch & Lever?

Also make sure you follow along on instagram for more regular updates, if your social media

proclivities swing that way.

Until next time!