Make Your Own Rock – Very Cheap

The Paper: “Electrodeposition of calcareous cement from seawater in marine silica sands”
The “magic” isn’t a joke, but it’s not instantaneous like a lightning strike. Here is the breakdown of how it actually works according to the research:
The “Secret Sauce”: It’s not just sand and electricity; you need seawater.
The Voltage: They use a very mild current—only 2 to 4 volts. For perspective, that’s about what it takes to power a small LED or a toy flashlight.


The Timeline:
Instant start: The chemical reaction begins the moment the power is switched on.


Solidification: In lab tests, the sand starts to noticeably “clump” and harden into a rock-like mass within just a few days of continuous stimulation.


Full Strength: To reach a durability comparable to concrete or a sea wall, the process takes about 28 days.
The Result: The electricity triggers the dissolved minerals in the ocean (calcium, magnesium, and carbon) to crystallize. These crystals grow between the grains of sand, acting as a natural glue or “mineral binder.”

https://coastsidebuzz.com/no-more-seawalls-no-more-beach-replenishment-according-to-northwestern-university-coastal-sands-can-be-cemented-with-mild-electric-stimulation-princeton-harbor-surfers-beach/

This Is Not A Joke

The biggest argument against coastal defences is cost. This is a remarkably low cost solution to a problem which afflicts a lot of the UK coastline.