Well clearly if you are using a 3d printer bed to heat a liquid there is a cost component involved in the decision making process ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
I think people start exaggerating how wet chemistry is easy and then take liberties on top of that and you get fail... pop-sci seems to really focus on making bogus chemical processing stories. Its not that intuitive or easy, it took Bohr to start figuring out chemistry in the year 1600.... but people act like its smithing by neolithics in 20000 B.C.
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In my opinion, its way harder then soldering, which is seen as a high end skill.
Come on, dude. Don't be ridiculous. BTW, plating & etching are two very different things, so that plating is possibly difficult has no bearing whatsoever on etching and vice versa.
We aren't talking Nobel level chemistry here. Moreover, poor Niels Bohr - he lived in 20th century, not 17th ... Basic chemistry processes, such as metal etching, were known for millennia, that we didn't understand why they work is not really relevant to the discussion in any way.
Moreover, if you buy a ready-made etchant, you don't have to do anything, just pour it into a tray. No need to even heat, just stir the solution every once in a while. Fresh ferric chloride will etch the board in 30 minutes even cold, no issues whatsoever.
If you buy dry ferric chloride crystals, all you need to do is to dissolve the crystals in water (doesn't even need to be distilled/deionized - if you are etching in a tray and not in a machine that could gum up it doesn't matter) to create a saturated solution i.e. until the crystals are not dissolving anymore. How are you making your tea or coffee if this is too complicated for you? Or, God forbid - cook a dinner?
That the OP used a 3D printer bed as a heater boggles my mind because all it would take is a drop of the etchant and the bed is ruined (never mind a brain fart causing the bed to move and splash the warm etchant all over the place). That's nothing to do with cost, more like outright stupidity (together with using that germicidal UV-C lamp). A water bath can be improvised in every kitchen and certainly costs less than a 3D printer.
Worse -
you don't need any of it! Ferric chloride will etch cold just fine (unlike ammonium persulfate, that one must be heated), it only takes longer. I have never bothered to heat my ferric chloride, the risk of making a mess if I happen to spill it is not worth saving a few minutes for me.
Here the problem is not the supposed complexity of the process but that the OP has obviously "winged" it somehow, not bothering to read instructions or thinking they can just skip & adapt the steps of the process without understanding them. I could understand this if it was 30-40 years ago when we didn't have any resources or guides to learn from, only books and some magazines - or, if lucky, some friend who could mentor us. So trial and error was often the only way to figure things out. But today? With tons of good guides online, both in text and video format?
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif)