Etching and Pedal Finishing Tutorial!

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1. Warnings!
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• This tutorial will involve corrosive chemicals, which have to be dealt with
accordingly. I’m a trained chemist and I still wear the appropriate safety
measures at all times, i.e. safety goggles and gloves. I do recommend a lab
coat or old clothes for the etching process.!
• If you get etchant on your skin, rinse it and clean thoroughly with soap. If
you get it into your eye, rinse it for at least 10 min with water and see a
doctor immediately!!
• If you have small children in the house, keep all chemicals safely stored away
and properly labeled. The last point is a must anyways, children or not!!
• I highly recommend doing this in a garage, tool shop or something similar or at least 

on an old desk. Do not use your living room table.!
• Use this tutorial at your own risk only.!
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I’m not trying to scare anyone away from trying etching and it’s actually not as dangerous as it may
sound right now. I just want this to be a safe experience for everyone involved. You don’t need to
look like me down below, although it sure looks sexy as hell. Just inform yourself about what you’re
dealing with and take the necessary safety measures. You’ll find 98% of the information you need
via wikipedia.!
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2. Acknowledgement!
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This tutorial is a mashup of other people’s tutorials and some bits and bobs I figured out on my
own. Check their tutorials for even more info:!
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• Cody (selfdestroyer) is using FeCl3 for his etching and is a constant inspiration:

http://music.codydeschenes.com/?page_id=2035!
• Graham’s etching tutorial: http://diy-guitar-effects.tumblr.com/etching!
• Dan (dminner) for general inspiration in all regards to graphics and design.!
• John (juansolo) and Cleggy for their work with Envirotex:

http://stompage.juansolo.co.uk/finishing.html!
• Marcus’ (mmlee) girlfriend for suggesting the rubber roller.!
• Brian @ madbean pedals. He’s the best host ever, offers great pcbs and has some tutorials
too: http://www.madbeanpedals.com/tutorials/index.html"
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3. Materials:!
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• Safety equipment: Gloves, goggles, old clothes/lab coat.!
• Aluminium enclosure!
• Wet sanding paper up to 600 grit preferably with a sanding block!
• Laser printer (I use a HP LaserJet Pro P1102W as per Cody’s suggestion)!
• High gloss paper (I use Sigel LP341 Photo Paper 135g 2-side glossy)!
• Household iron!
• Solvent (preferably isopropanol or acetone)!
• Painter’s tape!
• Soft rubber roller (one of those things)!
• Adhesive tape!
• Sodium hydroxide (NaOH) (or Iron trichloride FeCl3)!
• Used glass jar!
• Plastic container!
• Centre punch!
• Drill bits, stepper drill bit!
• Spray paint/airbrush…!
• Everything else is basically optional (spatula/flathead screwdriver, syringes,…)!
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4. Toner Transfer and Etching!
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4.1. Design/Graphics preparation!
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I use Gimp for all my graphics. It’s free and you can do amazing things with it and there’s a big
community for support. It has a steep learning curve however and took me a while to figure things
out. The main focus here is to get graphics that suits your style and is in black and white only. I
usually google for black and white images, but more often than note they are with gray as well,
rather than 2 bit. You can use the threshold control to get rid of some things and switch to 2 bit
later. I also spend hours and hours manipulating single pixels until I am content with my graphics.
Also, if you are using images from the internet, ask for the artist’s permission if applicable. I only
had to do it once, and the guy was really forthcoming and even sent me a HD image.!
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Do not make your graphics too complicated, especially don’t use too fine lines as I did in the
example below. Especially if you are a beginner, start with something simple and work your way
up. As with everything, this process takes a few tries to get the hang of it.!
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Make sure your drill marks are aligned and fit the pot spacing etc.! You don’t want to find out after
etching that your layout was wrong. Also, consider wether you are doing a regular or reverse etch,
i.e. is you design etched into the enclosure or is the design the raised part. The etched parts will be
the white/non-covered parts of your graphics. So you might need to invert your pic, depending on
what you are going for.!
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Once you’re done, mirror the whole image and print it to scale and cut it out. It has to be a toner
printer, i.e. laser printer to work. It won’t work with inkjet! Also, use glossy paper. The point is that
upon heating the whole thing later on, the toner won’t adhere as well to the glossy paper when hot/
melting, but rather transfers to the aluminium enclosure, thus giving us the etching mask. It can be
a bit tricky to find a combination that works for you. Once you find it, I recommend stocking up and
never changing back. There are various printer/toner combinations that work, but I use a HP
LaserJet Pro P1102W and Sigel LP341 photo laser paper. I’ve seen people use magazine paper
too.!

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Fig. 1: Graphics ready to use. Listening to music while preparing the design is crucial.!
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4.2. Enclosure preparation!
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125B is my go-to size enclosure, but this works the same way on bigger or smaller enclosures. For
bigger enclosures, just give it some more time.!
To get started, I wet sand the enclosure to 400 grit to get rid of surface roughnesses or dents. It
doesn’t have to be perfect, just get a good smooth surface.!
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Fig. 2: Before and after sanding to 400 grit.!
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I recently had the brilliant idea to screw the enclosure to a scrap piece of wood. This way I don’t
have to touch the hot enclosure during toner transfer and it can’t fall down leaving a dent on the
living room wooden floor. Don’t ask me why I specifically mention that. You don’t have to screw it to
anything, just remember to put something underneath the enclosure (stack of magazines, old
dishcloth), if the desk is worth protecting. Something that won’t melt by the way…!
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Fig. 3: Everything ready to go. Note that the enclosure is screwed to the wood from the back.!
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Finally, wipe the surface of the enclosure with some solvent to degrease it and get residual dirt off.
I usually use isopropanol or acetone.!
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4.3. Toner Transfer!
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Once you’ve come this far, tape the graphics face down (I was hoping this is self explanatory) to
the enclosure. Make sure it is well aligned with respect to the edges as you can’t change this later
on. I use small pieces of painter’s tape.!
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Fig. 4: Design taped down ready for transfer.!
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Heat up your iron to the highest setting without steam. Once it’s hot, place it on top of the
enclosure and let it sit there to heat up the whole enclosure and to give it an initial bonding to the

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paper and graphics. The enclosure will now have approximately 1.000.000 degrees, so do not
touch it from this point on. Remember, we fixed it to the piece of wood for that reason :). Once hot,
remove the iron and use your soft roller and roller the living crap out of it. Just go all out nuts and
roller back and forth. Then reapply the iron and do the whole thing over again. I usually do this 5-6
times for a 125B.!
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Fig. 5: Apply heat - then roller the thing.!
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However, I found that the roller was sometimes not enough to give a really good transfer. As was
Cody’s approach to use the tip of the iron and go over the whole thing in small circles. However,
combining the methods gave flawless transfers almost every time. So just iron the graphics with
the tip of the iron in a circular motion for a while too. Do not apply to much pressure or the lines will
smudge. After some time you’ll see the graphics shining through the backing paper.!
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Fig. 6: Graphics shining through. We’re almost done.!
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Once I’m confident that I did enough, I let the enclosure cool a bit and then toss it into cold water in
the sink and let it soak for ten minutes or so, until the paper is falling apart. Then, gently pull off the
paper backing. This tutorial shows a reverse etched enclosure meaning that the graphics will be
the raised part and there’s a lot of white areas so the paper removes easily. For regular etches this
can stick a bit more to the toner but you’ll get it off eventually.!
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Fig. 7: Let it cool and soak. Right: That’s what it should look like before you start pealing the paper off.!
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To get the smaller pieces of paper off the enclosure I gently rub it with my finger or use a soft tooth
brush. Also, I recently found that dish soap is doing a great job to get the paper off in combination
with the brush. Just be gentle, you don’t want to remove the toner. After this step you already have
a decent pedal decoration. Toner transfer alone or in combination with clear coat/epoxy will give
you a sturdy and professional look already.!
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Do not hesitate to redo this process if you’re not content with your result! It will take time to get this
process right. I remember doing my first toner transfer seven times, before the result was ok. Not
great, but ok.!
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FYI, this is the same process, I use for toner transfer on PCBs. Usually, using the roller alone is
enough for pcbs.!
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If you have some spots that should be covered with toner but are not, you can take nail varnish to
remedy those spots. It works well for FeCl3, but I seem to remember that it doesn’t hold up to well
against NaOH. What I do remember though, is the questioning looks on my collegues’ faces when
I came to the lab with red nail varnish in hand (in, not on my hands to be clear).!

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Fig. 8: Peal off the paper and lightly scrub the little bits of paper out with a tooth brush and soap.!
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4.4. Etching!
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Now this is were it gets interesting. First up, cover the sides of your enclosure with tape leaving a
collar at the top to fill in your etchant and put it into a plastic container. Speaking of etchant, this is
were we get our safety gear! I generally use sodium hydroxide (NaOH) solution. You can get that
stuff at your local electronics store and I assume at the hardware store as it’s basically drain pipe
cleaner. I use about 40g/100ml, which equals 10 mol/l. This is quite concentrated! Put the solid
NaOH into an old glas jar and add water. It will take a bit to dissolve and it will get hot too! For tips
and tricks regarding enclosure etching with iron chloride (FeCl3) head over to Cody’s tutorial linked
at the beginning. NaOH is not suited for PCB etching!!
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NaOH is highly corrosive and will eat holes in your shirt and trousers. FeCl3 is not as bad in
that regard, but will stain everything, so take care. You have been warned!!
I’ve seen/heard from people using hydrochloric acid (HCl) or even combinations of
hydrogen peroxide (H2O2) with sulfuric acid (H2SO4). Don’t do it. Just don’t. Believe me, it’s
not worth the risk. Yes, they work. But, these things are just way more dangerous than
necessary for this task. HCl will degas leading to you breathing corrosive gases in and the
H2O2/H2SO4 combination will give you „Piranha solution“ as it will eat up almost everything
and can give explosive mixtures. Just leave those things alone.!
Some people also use muriatic acid (diluted hydrochloric Acid (HCl)) or „acid magic“. I have
never tried using muriatic and acid magic is not available in my parts, so I can’t really
comment on that, but it’s a possibility.!
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Once all the solid NaOH is dissolved in water I slowly pour it on top of the enclosure or use a
pipette to do so. You’ll immediately see a rather vigorous reaction producing bubbles on top of the
enclosure and some quite nasty gases. Therefore, do it in a well ventilated room or outside, and
obviously try not to inhale the fumes.!
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I usually leave it for quite a while, around one hour. There will be some gunky dark stuff (some sort
of sodium aluminate) forming due to the reaction, slowing it down a bit. As long as it’s sizzling, it’s
doing it’s thing, so no need to worry. Also, as the solution is initially warm due to the dissolution
heat, it will be faster at first. I check it from time to time and might apply fresh solution. You can
also gently wipe the surface after rinsing it using a sponge or kitchen wipe to remove the gunk. It’s
obvious, but here it comes again: safety gear (gloves)!!
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Once you think it has the desired depth pour off the solution. It’s generally not a good thing to pour
chemicals in your drain, so you can either collect the batches and bring them to your local garbage
collection site or you can pour it down anyways with lots of water. Please, do not do the later with
FeCl3 solution.!
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Remove the tape and start to clean up the enclosure with the scratchy part of a sponge. You might
need to remove the toner with some solvent (again acetone or isopropanol will do the trick) or you
can sand it off. I prefer the first method as you can’t remove any depth from the etch that way. Also
sand the sides of the enclosure to remove any unwanted kinks and gunk. More likely than not
some etchant will creep in some air gaps in the tape happily etching away.!
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I might have to add that my etches are usually not too deep. They are sufficient to reveal the etch
after painting and sanding, but with a higher risk of sanding into non-raised areas. I might try
stronger concentrations or longer etching times in the future. Feel free to experiment and report
back.!
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You can leave it like that or paint the enclosure to give the etch more contrast. Whatever floats
your boat.!
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Fig. 9: Fill the top with NaOH solution and let the magic happen.

You can often see how the bubbles outline your graphics design.!
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5. Drilling, Painting and Revealing the Etch!

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5.1. Drilling!
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Next step is to drill all the holes. Use a centre punch to mark the holes and drill a small pilot hole
(2-3 mm) and then use a stepper drill bit to get to the desired diametre. This is the time to see if
your template lines up with the actual pot positions. I usually drill the enclosure before soldering the
pots to the PCB. Obviously, this only works if you already committed to boxing the effect prior to
testing it out, which is nearly always the case for me. But this way you can make sure there’s no
stress on the solder joints.!
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Fig. 10: Wait a second! This is not the same graphic as shown above!

You’r right, my etch was way too shallow (didn’t weigh the NaOH and just eyeballed it)

and the graphics had too much detail so I started over. No problem. Just sand the etch off and start again 

until you like the result or sanded away the hole enclosure.!
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As you can see in fig. 10 on the left, I had the graphics laid out so that the crosses marking the drill
spots were raised. I should have inverted that part, so that the cross was etched into the enclosure.
Makes centre punching and drilling easier. Not a big deal, though. Just use small drill bits and drill
slightly off-centred `till you’re content with the central position prior to widening the hole with the
stepper drill bit.!
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Fig. 11 shows the advantage of Lumberg style jacks. They can be easily cut with a knife or a
Dremel® tool making them extremely small. Regular sized jacks would not have allowed for this
arrangement. Especially since I started doing top mounted jacks, I never moved back. I will tolerate
the reign of side mounts no longer! Also while, we’re at it, please stop using crappy 3PDT switches.
You are investing lots of time and probably money into decorating your pedal and getting the best
sound from expensive mojo parts, you can afford the extra 2 € an optical or relay bypass.!

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Fig. 11: Test fitting and cramming in top mounted jacks. Impressive!!
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5.2. Painting and Revealing the Etch!
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Prior to painting wipe the whole enclosure with solvent again. I guess, it’s the brand of colour I use
(Duplicolor acryl), but it’s very picky to grease and other decontaminations on the surface. Darker
colours generally work a better with etches due to the contrast to the blank aluminium after
sanding. Just paint the enclosure like you usually would with multiple light coats. Nothing special
here really.!
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I did build a small spraying booth for the balcony, which works well. It’s a bit small, though. I usually
do only apply primer to the sides of the enclosure for two reasons. 1) The top will be covered in
Envirotex and will be durable because of that. If you only use clear coat, you might want to add a
layer of primer first to make it more durable. 2) The primer is way harder to sand afterwards and
the extra layer of paint can result in lost depth of the etch. It’s your choice to use it or not. There’s
pros and cons to both.!
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If anyone is wondering, the spraying booth is just a cardboard box with a hole in the top covered
with household transparent foil for better lighting inside and some transparent foil and a removable
garbage bag on the front. Once I sprayed a coat, I put down the green garbage bag and fix it to the
box with some pins to minimize dust particles on the wet paint. Overall, i do 2-3 coats of paint with
15 min of drying in between. For colour fades as with the example shown here, I just alternate the
colours starting with the brighter one and vary distance and angle. It’s not hard at all actually.
Lighter colours might be harder to fade into each other.!

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Fig. 12: Spray painting „booth“ and mounting for the parts.!
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After letting the paint dry overnight, Use a small piece of sanding paper (I use 600 grit) and some
small object to gently sand or scratch the paint of the raised parts. Cody’s iPhone charge is
legendary, I use a small piece of scrap wood (not only because European iPhone charges look
quite different and are unfit for the task). Depending on the details and width of the lines, I also use
a small spatula or a syringe needle to scratch off the paint. However, this technique is rather
unforgiving if you scratch anything but the raised surface (as you can see next to the pot marker of
the delay pot in fig. 13). If you use a spatula or something similar make sure to hold it strictly
parallel to the surface to minimise chances of scratching non-raised parts. !
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Be patient here. Rinse the enclosure every now and then and see how you’re doing. Take a good
drink, a comfortable chair and good lighting and just take your time.!
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Revealing the etch is the part where etch depth and paint thickness are crucial. If the etch is to
shallow or the paint job to thick you will likely sand into the surrounding areas. If you just lightly
sand into it and dull the paint job, this will be ok after clear coating or applying epoxy. If your depth
is too low, you can always go for a grungy, worn-in look, which will look cool too. Again, whatever
suits your style. Dan mentioned using steel wool to go over the whole enclosure for a used look.!
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Pro Tip: Make a decent photo once you think you are done and zoom in to look for spots you might
have missed. Also using magnifiers and/or angling the enclosure will help a lot to see fine lines you
might have missed.!
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However, do not overdo it. Sanding for too long often too get the last detail often does more harm
than good for me. Just know when to be satisfied and find the balance between your OCD to have
a perfect pedal and a result that is actually very, very good already.!

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If you do mess up and you think it’s a deal breaker, remove the paint with solvent (preferably
acetone, works very well for acrylic paints) and start over with painting. I tried to apply paint to
small areas to fix mishaps with a Q-tip, but it will still be very obvious. Also masking the rest off and
applying paint locally will make it worse. Believe me, I tried.!
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Fig. 13: Prior to sanding/scratching with the necessary „tools“ and the (almost) end result.!
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Speaking of masking, I’m inserting a pic of a two-coloured etch I did a while back to give some
other examples here. With this one, I first masked of all the parts shown in red by cutting out what
felt like a thousand tiny pieces (2x2 mm) of painters tape. After painting everything with two coats
of blue and drying, the tape was removed and all the blue parts were masked before applying two
coats of red. Sanding the raised parts gives the end result. !
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Obviously, two-coloured etches are less work when you have big square areas to mask as shown
on the Evil Twin, which was etched and painted by dminner. Wow, that sounded really douchy and
ungrateful. I’m trying to say, it doesn’t have to be a pain in the butt to look good. Actually, I envy
Dan for his skills in designing artwork a lot. Finally, for reference I put a regular (non-reverse) etch
as an example. The graphics are the etched parts filled with paint and the rest of the enclosure is
raised.!
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Fig. 14: Two-coloured paint jobs and a regular (non-reverse) etch.!
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After sanding you have two options. Clear coating or using epoxy. Again, this is a choice of taste
and time. Nowadays, I tend to use clear coat the sides and use epoxy (Envirotex) on the top. I just
can’t find the patience to do epoxy on the sides, which always seems to be a pain in the butt. Clear
coat only is decent enough, but epoxy just adds that extra bit of bling-bling and makes it very
durable.!
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6. Applying Epoxy!
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This is the part where I basically copy John and Cleggy, so thanks again gents!!
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For preparing the epoxy mix, just follow the instructions of your epoxy brand. For Envirotex it’s
mixing equal amounts (by volume, not weight!) of the prepolymer and the hardener (the yellowish
part - it will get more yellow with increasing storage time. It’s a long chained amine, which oxidises
to form nitrous oxides, which are brownish. Hurray for Science!!) I use syringes to get the amount
correct, but you can also eyeball it. You can probably get syringes at your local pharmacy and you
can reuse them as long as you know which one was used for which part of the epoxy. For a 125B I
use 3 ml of each component, so 6 ml in total. Obviously, the amount depends on how thick you
want it to be. If you are using 9 mm pots, be aware that only a very thin coat will work as the
threads of the pots are quite short.!
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Next up, mix the compounds thoroughly. At first you will see those streaks in the liquid as you mix
it, which will vanish after some time as an early indicator for good mixture. Keep mixing for a while
just to make sure. If the epoxy isn’t mixed well enough there can be some soft patches after curing,
which you can’t harden later on, meaning you probably have to redo all the painting, sanding and
so forth.!
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Fig. 15: Measure carefully. Initially you can see the two phases. In the end, it should be very homogeneous.!
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Next, prepare the enclosure. Tape all the holes from the inside, wipe the surface (without solvents)
to remove any dust and level the enclosure (I use a small mechanic’s level). Especially with thicker
coats, uneven coatings can happen and be quite obvious. Then, fill the taped holes with epoxy and
cover the entire surface. Filling the holes will prevent any flow marks and thickness differences
around them due to surface tension. You can leave them and spare yourself the drilling, but I do no
recommend it. It’s easiest to just pour the epoxy on the enclosure and then spread it. I use a
disposable pipette for that, but a popsicle or anything similar will work just fine. Make sure to pay
special attention the edges and push the epoxy really close. The compound will shrink a bit when
curing and you don’t want the edge to be wobbly. Surface tension will most likely prevent any
dripping down the sides if you’re careful. If it does run down the sides, just wipe it off. Don’t use
acetone here as it will dissolve the paint as well.!
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The next step is probably the most fun. Exhale onto the enclosure to pop all the air bubbles! Then,
just cover the enclosure with a box and let it sit for three days prior to drilling. Check on it
during the first hours to see if there is anything dripping down the sides or if there are new air
bubbles. Depending on the stage of curing and how viscous the epoxy already is, you can still pop
them by exhaling. If not, using a lighter to warm the area up lightly, so it will get less viscous and
flow into the hole. Don’t stay on the epoxy with the flame or it can darken (or possibly burn). Do not
touch the epoxy during drying or you’ll leave fingerprints (again depending on the progress of
curing). The whole curing process can be sped up by using an oven. I found that 3 h at 60 °C is
enough to give a fully cured and ready to drill enclosure. However, due to the lower initial viscosity
at increased temperatures, it’s also easier to have drippings and uneven coatings. Also, do NOT do
this in your kitchen oven. Use a dedicated toaster oven or something..!
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Fig. 16: Pour on the epoxy, and spread it to the edges.!
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Once cured (seriously, it takes three days), remove the tape and drill out the epoxy. Drill a pilot
hole and then use a stepper drill bit at relatively high speeds. I had the problem with regular drill
bits, that especially at low speeds it’s possible that the drill bit lifts off the epoxy leaving you with a
discoluoured/foggy area, where there’s air between enclosure and epoxy. If that happens, see if it
is covered by the washers before deciding to start over (Wow! That’s a lot of mentioning to start
over…). Same thing can happen later when pushing the pots through the holes. If it won’t go
through easily don’t push too hard. Maybe the drill hole is not entirely cleaned off the epoxy…!
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Applying epoxy to enclosures with waterslide decals is exactly the same by the way. John and
Cleggy cover applying decals in their tutorial as well. Link is found at the beginning.!
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Fig. 17: It will be messy! Clean up and wipe your enclosure with a cloth to get it sparkling.!
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This is the end of all the cosmetic work! You should now have a ready-to-populate enclosure.!
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7. The End Result!
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I won’t say anything about boxing effects. Just test them out prior to boxing. It’s a pain to realize
something’s off and disassemble it again. General wiring tips can be found here: 

http://www.madbeanpedals.com/tutorials/downloads/MBP_FootswitchWiring.pdf"
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Fig. 18: Take your time with the guts. You want them to fit the exterior ;) Also, choose the right knobs.!
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! Fig. 19: All done! and some detail shots.!
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You’re still here? Wow! Thanks for reading this far! By now you should have an effects pedal that at
least looks good and hopefully sounds accordingly. If you have any questions, comments, praise or
think there’s something missing, etc. send me an email at quantumfx[ät]gmx[dot]at, drop me a PM
on the madbean forum (username: m-kresol) or leave a comment on my blog.!
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Für die deutsche Version, klickt hier.

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