One of the first steps in technological is the ability of a civilisation to forge tools* humans achieved this by using fire and creating forges.

There are obviously underwater heat sources but I don't anticipate our sea-folk being able to use the heat from underwater volcanoes any more than we can above ground!

How could an underwater civilisation generate and control the heat required to forge metal as we did above ground?

*This question actually started asking how they would build computers but I've got back several steps!

  • $\begingroup$ After discussion I've re-opened this for now, however it's potentially a duplicate of: worldbuilding.stackexchange.com/questions/1452/… $\endgroup$ – Tim B Nov 6 '14 at 15:55
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    $\begingroup$ I don't want to make the dupe-or-not decision by mod hammer as we've not had many duplicates yet on the site. It will be better to let the community make the decision. So I'll leave it down to the community whether to close as dupe or just say the other question is related and leave this one open :) $\endgroup$ – Tim B Nov 6 '14 at 15:56
  • $\begingroup$ Liath - Can I answer the computer question? I have an idea or two. BTW, Tim, I'm not going to vote to close until some answers pop up and we see how the question evolves. $\endgroup$ – HDE 226868 Nov 6 '14 at 15:57
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    $\begingroup$ @HDE226868 created - worldbuilding.stackexchange.com/questions/3722/… $\endgroup$ – Liath Nov 6 '14 at 16:05
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    $\begingroup$ You don't. The tech bootstrap sequences do not exist. $\endgroup$ – Joshua Mar 16 '15 at 19:31

I don't think under water vents are that far off from being a possibility. Underwater vents can reach temperatures of over 800 °F putting them in the range of melting lead. While difficult to imagine, a completely closed crucible melting metal contained in the top of the crucible which is then pulled by gravity down into a crude mold of knife/spear head shapes may be possible with lava which can reach temperatures around 700 to 1,200 °C (1,292 to 2,192 °F). Depending on the temperatures just below the vents it may be possible to get into more structural metals like bronze or copper in this way.

This of course requires active volcanoes either near the ocean (like the Hawaiian islands or oceanic vents/volcanoes).

Another possibility would be electrolysis; some of the magnesium produced in the world today is obtained from sea water and an electrolytic process. If chemistry is something your aquatic races gets pretty good at its possible that they could "forge" items from carefully chosen templates using electrolysis to coat the template with the desired material (for example a piece of stone or bone electro plated with magnesium)

Just the electrolysis of magnesium alone may be enough to produce forge level temperatures since magnesium can burn at over 5000 °F.

Your aquatic creatures would likely need to be using techniques and tools that we don't have analogs too based on the environmental differences but I do think there is the possibility that they could effectively work with metals.

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    $\begingroup$ A good answer, however how would you create/work with these forges when you have no way to turn off the heat to get close enough? $\endgroup$ – Tim B Nov 7 '14 at 9:09
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    $\begingroup$ The problem here is that water conducts heat better than air. A Blacksmith in air is way better protected from heat than he would be in water. Also, because of the water pressure, melting temperatures should be slightly higher than at the surface (exactly how much, I am not sure). $\endgroup$ – kutschkem Nov 7 '14 at 9:39
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    $\begingroup$ Both of these comments are correct of course, and I do point out that they would need techniques and tools we can't relate too. But necessity is the mother of invention. $\endgroup$ – Culyx Nov 7 '14 at 14:42
  • $\begingroup$ @Culyx but how would you make the crucible? $\endgroup$ – RonJohn Oct 12 '17 at 4:39
  • $\begingroup$ @Culyx necessity might be the mother of invention, but usefulness is the key to evolution, and fins/flippers are a whole lot more useful to an aquatic species than arms and opposable thumbs (which is why you don't see any). $\endgroup$ – RonJohn Oct 12 '17 at 4:41

To build on the answer provided by Culyx, I suspect it would be possible for a bioelectric race, to learn advanced forms of electroplating & electroforming.

My limited understanding of electroplating is:

  1. Dissolve a metal
  2. Develop a 'mandrel' in the desired shape
  3. Utilize an electric current which, in some way, bonds the metal to the mandrel (not exactly sure on the details of how...)

All of the above steps seem likely to be possible & even possibly easier, in an aquatic environment.

Electroforming is actually even more interesting, in that it is used to create highly detailed as well as much thicker products.

Electroforming could be used to actually produce things such as knives, swords, etc... out of metal, (not just a coating of metal on something else more easily formed).
Additionally electroforming can be VERY accurate in reproducing highly detailed forms/mandrels, even, if I understand correctly, on the nano scale (the scale of the transistors our current computer chips are measured in).
This would very much support the idea of making computer circuits in a similar form as our PCBs (Printed Circuit Boards)... to go with your other post on that topic (and what got you thinking about this one).

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    $\begingroup$ So sentient electric eels that produce their metal using electroplating (electroplating works by using electricity to pull metal ions out of the water and onto the surface being plated)? Nice idea :) $\endgroup$ – Tim B Nov 7 '14 at 13:22
  • $\begingroup$ Nice expansion on the electrolysis concept, hadn't heard of electroforming before. $\endgroup$ – Culyx Nov 7 '14 at 14:45
  • $\begingroup$ @TimB ah, so ionization is the reason the bonding works... then is the charged state, or lack thereof, in the thing to be plated important?... I mean do you have to have an item that has an opposing charge to that of the metalic ions, in order to plate it? (this could make the feasibility of electroplating less likely if the race has to have very specific materials which they can plate ... guess I should read up on it more lol) (oh & thanks @Culyx!) $\endgroup$ – MER Nov 8 '14 at 0:02
  • $\begingroup$ @MER "All of the above steps seem likely to be possible" no, because the electric current will get dispersed into the surrounding sea water. $\endgroup$ – RonJohn Oct 12 '17 at 4:43
  • $\begingroup$ Hey @ RonJohn. As I understand it electroplating is typically done in a conductive medium, usually liquid. The trick would likely not be with the presence of water but: 1- making sure the chemistry is right 2- containing the effect so the current runs from the one item, through the medium and into the other (and minimize running the current to something else). instructables.com/id/Clean-and-Simple-Electroplating wikihow.com/Electroplate-Metallic-Items en.wikipedia.org/wiki/Electroplating $\endgroup$ – MER Oct 13 '17 at 16:18

Think of copper. It occurs native (no need to melt ore), and it is possible to cold forge it (again, no high temperature required). I see no reason why copper couldn't be found underwater.

  • $\begingroup$ regarding cold forging, you would have an issue with accelerating a hammer up to speed in a viscous environment. You could get around this with a sufficiently massive striking object, but it would need some work to set up. $\endgroup$ – superluminary Nov 7 '14 at 11:56
  • $\begingroup$ @superluminary wouldn't creatures living underwater have found a solution? After all, using a spear underwater must require some effort... $\endgroup$ – Redwolf Programs Apr 16 '18 at 15:58

You might see advanced stone age technology

I think you would be most likely to see stone age style tools. Flints would be common. Driftwood would be available. Bones would also be an option. Mining and smelting metal would be tough. Keeping a mine free of drifting debris would be a tough challenge, and extracting it without the ability to deliver a good strong hammer blow would also be hard.

Water viscosity

Forming these into tools would be more challenging as you would need to work against the viscosity of the water when striking rock against rock, but it would probably be possible given time and effort.


A bigger issue would be the presence or absence of hands (or similar) on your aquatic species. It's likely humans evolved hands initially to help with climbing, and later for throwing rocks. Neither of these avenues would be open to an aquatic species. Perhaps your species returned to the water, like seals and cetaceans on earth.

Can you describe your species in more detail?


Let's assume however that they do want to forge metal.

Water boils at 100 degrees at sea level, significantly below the melting point of any useful metal, and turbulently boiling water not a good environment for forging anything. I would suggest that the creatures might want to evacuate the water from inside the forge, perhaps by creating a vaccuum, or even by filling the region with gas of some kind, maybe piped from the surface. A dry region might be a magical, future sci-fi thing for them.

Alternately they could go to the surface to forge, perhaps a floating raft or beach. This would be similar to us going into space.

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    $\begingroup$ A better analogy than us going into space would be us going underwater surely? $\endgroup$ – Tim B Nov 7 '14 at 13:23
  • $\begingroup$ @timb - yes, you're probably right, I was assuming a deep living species. $\endgroup$ – superluminary Nov 7 '14 at 17:37
  • $\begingroup$ I think your comment about bones is a great point... I suspect bones would be used as the basis for most early tools (a replacement for wood). Also I definitely agree on the hands comment... Seems really unlikely that advanced technology can be developed without grasping appendages... $\endgroup$ – MER Nov 7 '14 at 23:49

The more I think about these questions the more I think that an amphibious animal would be much more likely to bridge this gap.

But as far as this goes, of course being able to create tools that only need physical manipulation could be fairly simple, such as breaking rocks for spearheads, etc. of course a shaft for that spear might be hard to come by. Since you need someway to manipulate tools, even to make tools, they will need dexterous limbs (possibly even a tongue) to work them. I would expect most tools to be 'grown' somehow and shaped. Along the lines of pearls and such.


Does it need to be forged in the exact way we think of forging? Water is a great solvent for a lot of nifty things. I would expect they could deposit metallic structures in the shapes and alloys they need at least as easily as they could develop ways to heat up metal in a quenching environment.


Another solution is not having civilization at all, just one single organism - living ocean. I drafted such world here. Such organism can harness energy of the sun, convert it to electromagnetic field and do stuff. It is basically Type I civilization on http://en.wikipedia.org/wiki/Kardashev_scale - and grows from there. No need to coordinate between those pesky individual organisms.


First of all I would like to mention that our first tools were (like sharpened stones or stone hatchets) of course can be created without the need of heat/fire/forging. Works like this require agile, flexible extremities such as fingers. Fingers seems to be rare underwater but agile tentacles aren't as far as I can tell.

That said on to forging (were agility also comes in handy).

As I just found out sparklers actually burn under water (given some small shell). Wikipedia tells me that sparklers burn at temperatures of about 1000°C high enough for copper and gold to meld. So given a world where the "wood" of some underwater plants is basically the same material as sparklers making underwater fire seems plausible. Tricky parts remain still to be solved

  • enlighten the fire underwater in the first place
  • I have no clue about casting under water. You basically have a fluid in fluid. Could do weird stuff...

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