So, my very first etch wasn't originally intended to be an etch....

[EBK]

Slight update:  If I wanted to spend $75, I could buy a gallon of alkaline cyanide-free copper plating solution that might work.  But, I'm not going to spend that for this project.  (But, I definitely would at least think about spending that amount of money if I could find an industrial electroplater willing to accept a small one-off project.)

[Fancy Lime]

The coins I plated were a US nickel and a US quarter.  Both are made of cupro-nickel, but in different copper-nickel ratios.
Regarding the zinc dissolving, it readily dissolves in the solution even with no voltage applied.  I was afraid of applying too high of a voltage for fear of merely adding a flaky burned crust of copper, which would simply wipe away easily when done.  Adding a nickel plate to the zinc beforehand makes sense, except the DIY method still uses vinegar to create an acidic solution, which will still happily eat away at the zinc.

Ah, we might be getting closer. The zinc does not dissolve "even with no voltage applied" it should dissolve "only with no voltage applied". As long as the zinc is under enough negative voltage (meaning more negative than the difference in electro-chemical potential between copper and zinc) compared to the copper anode, copper deposits on the zinc. When there is less or no voltage (or even reverse voltage), zinc acts as the anode and is being dissolved. That is why zinc is used as a "sacrificial anode" in ships, oil platforms and such. A chunk of zinc oxidizes away in the water thereby protecting the more noble iron of the hull (with which it has electrical contact) from oxidizing (https://en.wikipedia.org/wiki/Galvanic_anode). What works in seawater works much faster in vinegar. So you need to apply voltage first, then put it in the bath, lest zincy go bye bye

Andy

[EBK]

Ah, we might be getting closer. The zinc does not dissolve "even with no voltage applied" it should dissolve "only with no voltage applied". As long as the zinc is under enough negative voltage (meaning more negative than the difference in electro-chemical potential between copper and zinc) compared to the copper anode, copper deposits on the zinc. When there is less or no voltage (or even reverse voltage), zinc acts as the anode and is being dissolved. That is why zinc is used as a "sacrificial anode" in ships, oil platforms and such. A chunk of zinc oxidizes away in the water thereby protecting the more noble iron of the hull (with which it has electrical contact) from oxidizing (https://en.wikipedia.org/wiki/Galvanic_anode). What works in seawater works much faster in vinegar. So you need to apply voltage first, then put it in the bath, lest zincy go bye bye

Andy

Well, that may be enough inspiration to experiment more.  I can start with burned flaky copper and work my way backwards, I suppose.I will probably give nickel plating a go first (I promise not to fall for the Ernie Ball Pure Nickel strings are actually pure nickel part though.)

That just leaves me with the problem of successfully remasking the enclosure first.  Carefully retracing my steps, I may be using a higher setting on the iron than I did originally, with the potentially mistaken belief that an incomplete transfer must be due to incomplete toner heating....

[EBK]

The wonderful thing about this being my own thread is that I can get away with a detour like this:

So, I want to take a few minutes and explain a bit of my motivation here.

I've built a bunch of pedals, and with the advice and inspiration from this community, I feel like I've progressed in leaps and bounds in terms of quality over time.  I'm sure many of you feel the same about your own work.  This creates an interesting problem in that I have a pile of pedals that sound amazing, but are not up to my current standards visually.  When I can, I'm trying to spend some time remedying that by rebuilding these pedals so I can proudly show them off again.

I love my Brassmaster that was essentially a straight up kit build through generalguitargadgets.com (R.G. did the PCB layout and GGG provided the parts, including the board, and documentation).

At the time I originally built it, my graphics skills amounted to freehanded Sharpie work with no preconceived idea of what the final product would look like.  Mistakes could only be fixed by adding more ink or paint, depending on what type of Sharpie was in my hand at the time.  I happen to like what came out of that effort, so I wanted to pay tribute to my past here by maintaining the essence of that early artwork while bringing the pedal up to my current standards.  I happen to have two Brassmaster boards, so I'm doing this twice, with a lot of freedom to experiment.  One of these will be a gift* to my younger brother, who recently took up playing bass.

Here is a pic of my original Sharpie-powered build next to the hardware-fit-test-stage version (LED is currently missing) that will eventually go to my brother:

This one is the conventionally-etched aluminum enclosure.  The zinc enclosure, in whatever form it ultimately takes, will remain part of my personal collection.

*Gift with strings attached.  He can enjoy it for as long as he wants, but he won't be allowed to sell it or give it away.

[Kipper4]

Yep it turned out nice Eric.
Good job

[deadastronaut]

came out lovely man, nice touch with the gold knobs, very classy. 

gold spray, sometimes the simplest solution is the best..cool

[EBK]

Thanks, guys!  Glad you like it.

So, after repeatedly coming up with failures in each attempt to remask the zinc enclosure for another round of electroplating experiments, I decided to try boiling the damned thing out of desperation:

Zinc alloys are pretty porous, so perhaps some residue from my process has been creating problems. 

Update:
Nope.  That didn't solve it.

I'm out of ideas here.  I have no idea why this worked once, but apparently never again. 

[EBK]

Some new theories on my recent toner transfer failures.
First, I tried a rougher surface (1000 grit rather than polished), and the results were slightly better, but still in the failure category.  I'd much prefer going with a polished surface though .

Second, subtle amounts of inadvertent steam could be wrecking things.  One difference between my recent attempts and the original successful masking is that the enclosure has been drilled.  My surface prep has involved wet sanding, rinsing, drying, and acetone wipe.  However, I have not been paying attention to the inside of the enclosure, which may still have water droplets.  Before drilling, it wouldn't have mattered much at all, but now, any water inside the enclosure is converting to steam which tries to escape through the drill holes.  This would seem to explain the dark patches where a faint amount if toner transfers, but doesnt form a single cohesive layer sufficient to pull the emulsion away.

Will try preheating the enclosure to boil off all excess moisture and report back.

[Fancy Lime]

Hi Eric,

some of my attempts at hot toner transfer looked similar to the one on your last photo. So I tried cold transfer and haven't looked back. It has so far never failed me and produces a very sharp and even transfer. No idea if it will work for a zinc enclosure but in case you want to try, here is what I do:

I have my graphics printed at a copy shop because I don't have a printer. However, any laser printer set to full contrast on a glossy paper should do.

I use a mixture of 8 parts Ethanol and 3 parts Acetone to soften the toner and make it stick to the enclosure. Acetone irritates the skin, so you might want to wear disposable Nitrile gloves or household cleaning gloves (latex or neoprene) for that. Apply enough so that the surface is completely wet. The enclosure must be level before applying the Ethanol-Acetone mixture, so it doesn't all run down the sides. Place a wooden block or something in the enclosure so that you can apply pressure to the whole surface later without denting the surface.

When the surface is wet, place the graphics. You want to be fairly quick (no rush, just don't wait minutes between the steps) because the acetone will evaporate from the mix. The paper can be moved easily until you apply pressure. Once it is in place, press it to the surface with your hands for a few seconds. I give it my full body weight, not sure that is necessary though. It should now stick enough to take your hands off and place something flat an heavy on the box for a while. One of those pyramid-shaped Acme weights would be ideal but in case you're not sharing your garage with Wile E. Coyote, a cutting board with some bricks on top will do just as well. I let it sit like this for an hour. Longer is definitely no problem, shorter may be ok too, don't know.

Take the weight off, let the paper dry (should only take a few minutes if it's not dry already). Put the whole thing in water to soak the paper. Depending on the paper it should now peel right off. If it does not, you may need to gently rub it off with your fingers. When I want to use the tone directly as a decal without etching, I remove the last bits of paper with a vinegar soaked sponge.

Hope that helps,
Andy

[EBK]

I use a mixture of 8 parts Ethanol and 3 parts Acetone to soften the toner and make it stick to the enclosure.

But, all my ethanol is the hoppy, effervescent kind.

Acetone irritates the skin, so you might want to wear disposable Nitrile gloves or household cleaning gloves (latex or neoprene) for that.

I've been practically soaking in the stuff.  Of course, I also don't wear goggles or a dust mask when cutting or filing my fiberglass boards....

I'll definitely have to read through this in more detail later.  Surrounded by turkey and turkeys at the moment in this house, and they are keeping me distracted.   

[Fancy Lime]

But, all my ethanol is the hoppy, effervescent kind.

That kind goes with the turkey. You can distill the leftovers when you have an attack of "I'll never drink again" party remorse in the morning. But then again, distilling while hung over sounds awful. Strictly no soaking the turkey in acetone, though. It makes for a festive looking fire but sort of ruins the taste.

BTW, forgot to include the link to the original instruction from where I got the technique:
http://www.instructables.com/id/Heatless-cold-Toner-Transfer-for-PCB-Making/

Happy Thanksgiving,
Andy

[EBK]

Andy, I'm definitely going to give that cold transfer method a shot.  I had yet another hot transfer failure yesterday, ruling out steam being the culprit.

[EBK]

So, unofficially, I've rediscovered Teflon.  Cold transfer failed too.....  Maybe I'll try copper plating the whole thing then applying a mask.  Otherwise, I have no idea what's going on here.   

[EBK]

Note, this is a failure report.  Writing the following has about the same value as not writing it.  In other words, I'm only providing further documentary proof that I have no idea what the hell I'm doing.

I've revisited an old project only to fail again to get toner to stick to my newly invented Teflon substitute.

I've sanded my zinc enclosure and used copious amonts of acetone to clean it.  Then, for the first time, I tried sticker backing as a toner transfer medium, the whole time thinking, "please don't destroy my brand new laser printer."  The toner printed very successfully to my sticker backing paper.

Then it completely failed to stick better to the zinc alloy.   

I also briefly tried more cold transfer, but it also stuck to the paper better than the zinc....

I really need to find the absolutely most fool-proof method of toner transfer.