Brass Clock Face Etched With PCB Techniques

Over the last few months, [Chris] has been machining a timepiece out of brass and documenting the entire process on his YouTube channel. This week, he completed the clock face. The clock he’s replicating comes from a time before CNC, and according to [Chris], the work of engraving roman numerals on a piece of brass would have been sent out to an engraver. Instead of doing things the traditional way, he’s etching brass with ferric chloride. It’s truly artisan work, and also provides a great tutorial for etching PCBs.

[Chris] is using a photoresist process for engraving his clock dial, and just like making PCBs, this task begins by thoroughly scrubbing and cleaning some brass with acetone. The photoresist is placed on the brass, a transparency sheet printed off, and the entire thing exposed to four blacklights. After that, the unexposed photoresist is dissolved with a sodium carbonate solution, and it’s time for etching.

The clock face was etched in ferric chloride far longer than any PCB would; [Chris] is filling these etchings with shellac wax for a nice contrast between the silvered brass and needs deep, well-defined voids.

You can check out the video below, but that would do [Chris]’ channel a disservice. When we first noticed his work, the comments were actually more positive than not. That’s high praise around here.

17 thoughts on “Brass Clock Face Etched With PCB Techniques

    1. Pretty much everything he does on his youtube channel is beautiful like this. I have been hooked on his clock making videos for a while now. My only hope is he never finishes that clock, so that he can keep putting out the awesome videos!

  1. I’ve been watching the ClickSpring videos for the last couple of months and every time I’m left in awe! And wanting to try it myself. But I know the ease with which he makes the parts indicates he’s a master of his art, not that it’s easy. Truely beautiful handiwork!

  2. If you’re not exactly a clock expert and just want to DIY a nice fancy clock face for a special gift, this would be a really nice process and then instead of machining out the centre of the face, you could attach an off-the-shelf clock mechanism in it’s place.

  3. I didn’t see the term used in this article, but this process is called chemical milling. Of course draino works as well as several other corrosive chemicals.

    In thin brass or other metals, it can actually eat completely through the metal. This has been used in the past by fine-scale modellers as well as for instrument faceplates.

    1. Yes. I’ve seen it used in boat model making. Where super fine detail is needed. Like the railing of a boat. There’s whole little cottage industries of guys etching parts out with super fine detail. Some of the clever ones are made to kinda bend, and fold up, to make more of a 3D structure.

    2. I build 1:35 scale tanks, and lost of kits come with a sheet or two of etched brass parts, most often for gratings, but frequently also ID plates, latches on storage bins, gunsights, and other tiny fiddly bits.

    1. Apparently in Roman times both were in common use. In general Roman numerals were additive ie I II III IIII V VI not subtractive such as IV. Choice for clocks has been also variable. More of a puzzle is why clocks often use a mix such as IIII for 4 buy IX for 9? Wells Cathedral clock uses IIII and that’s been there for a while (600 yrs or so) but Big Ben uses IV – but that’s modern having only been there for 150+ years.

      1. Part 2! equally interesting is the suggested origin of the ‘numbers’, with low numbers related to the human hand. I II III IIII then become obvious for the 4 fingers (lends further weight to IIII not IV?) 5 is the thumb + index finger spread in a V with the other fingers clenched. 10 or X is a V on one hand ‘added’ to the V of the other hand – ingenious! Means even illiterate people can count and write to 10 easily with just 3 symbols. It is also suggested as the reason they were used for clocks, remembering when clocks first appeared on buildings such as church towers the vast majority of the populace were illiterate.

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