Crystals, at least those hawked by new-age practitioners for their healing or restorative powers, will probably get a well-deserved eye roll from most of the folks around here. That said, there’s no denying that crystals do hold sway over us with the almost magical power of their beauty, as with these home-grown copper acetate crystals.
The recipe for these lovely giant crystals that [Chase Lean] shares is almost too simple — just scrap copper, vinegar, and a bit of hydrogen peroxide — and just the over-the-counter strength versions of those last two. The process begins with making a saturated solution of copper acetate by dissolving the scrap copper bits in the vinegar and peroxide for a couple of days. The solution is concentrated by evaporation until copper acetate crystals start to form. Suspend a seed crystal in the saturated solution, and patience will eventually reward you with a huge, shiny blue-black crystal. [Chase] also shares tips for growing crystal clusters, which have a beauty of their own, as do dehydrated copper acetate crystals, with their milky bluish appearance.
Is there any use for these crystals? Probably not, other than their beauty and the whole coolness factor of watching nature buck its own “no straight lines” rule. And you’ll no doubt remember [Chase]’s Zelda-esque potassium ferrioxalate crystals, or even when he turned common table salt into perfect crystal cubes.
[ladyada] has republished an interesting snippet from the synthDIY mailing list. [David Dixon] discusses the actual chemistry behind ferric chloride based home circuit board etching. He concludes that ferric chloride is essentially a ‘one-shot’ oxidant. It can’t be regenerated and can be difficult to dispose of properly. The use of acidified copper chloride is a much better path and becomes more effective with each use, as long as you keep it aerated and top up the acidity from time to time. This etchant solution is actually the result of initially using hydrogen peroxide as an oxidant along with muriatic acid. You can see us using this solution in our etching how-to and while creating the board for our RGB lock. For more information on using hydrogen peroxide, check out [Adam Seychell]’s guide and this Instructable.
Aside: [ladyada] has added the receiver code to the Wattcher project page.
Making a PCB is very simple; it does not consume a lot of time and the results look professional. After reading this How-To and watching the step by step video, you will be able to make your own PCB in your workshop using just a few inexpensive materials.
Many people use protoboard and point-to-point wire everything, but needing multiple copies of the same circuit is the reason that forces many away from using protoboard. After making your first circuit board, you might not point-to-point wire anything again!
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