Welding in Space isn’t just cool, it’s entirely different from welding on Earth. While we expect that very few of our readers are going to have the luxury of welding outside Earth’s stratosphere, we know you will enjoy learning about the extreme welding undertaken by Earth’s greatest adventurers, up in space.
How Does Metal Behave in Space?
What most people don’t know about metal in space is that it behaves differently to its counterparts here on Earth. As you know, when you weld on Earth you usually heat the metal up to very high temperatures using either MIG or TIG welding gas, depending on your preferences. In space, however, welding can happen without your input at the most inconvenient times.
The short answer is that in space, metal sticks, but the truth is a little more nuanced than that. First, the metal must be unprotected, connect with some force, and lastly, be of similar metal. The chance that metal could accidentally start sticking together originally presented a worry for astronauts needing to fix issues on the International Space Station – what if the welding gun started sticking to the space ship?
How to Stop Your Tools from Sticking in Space
In truth, it is unlikely that your tools would stick to the space station because they will have a protective layer of oxygen which will prevent the sticking from occurring. If you were to remove the thin layer of oxygen from the surface of the tool, however, you may find that the tool could stick. Removing this layer would be quite difficult, thankfully, as it’s only because of oxidisation on Earth that our metal doesn’t stick together like it would in space.
To be sure that valuable tools aren’t lost in space, however, precautions are often taken to reduce metal-to-metal contact. This might mean coating your welding in plastic or ceramic where possible.
Cold Welding
The fact that metal sticks together is actually known as ‘cold welding’ and it is a process that has been used on Earth for centuries, often without properly understanding the science behind the phenomenon. Cold welding can usually only happen in a vacuum when the oxygen layer is removed, and the lattices of atoms on the sides of the metal objects that are going to connect.
This means that for the metal to stick together like two pieces of a jigsaw puzzle, the metal needs to be smooth and alike. You could not cold fuse copper to gold because the atom structures are too different. Dirt and irregularities in the metal will also prevent cold welding, as well as jagged surfaces at the point of welding.
If the metals can fuse together and the right circumstances are present, such as; no protective oxygen layer, smooth edges and they are the same metal, then it will happen immediately. A bit like tipping a glass of water into another glass of water, the metals will join together and become the same piece.
Has Cold Welding Been Done on Earth?
Cold welding experiments have been completed on Earth so that we can learn more about it and prevent accidents in Space from ruining valuable technology, but as mentioned earlier, the concepts behind cold welding have been used in centuries past.
Forge welding actually bears a lot of similarities to cold welding – although blacksmiths use fires to heat the metals, they aren’t so hot as to liquify the metal like in gas welding. Instead, those fires serve to burn away the protective oxygen layer and to smooth the edges of the metal – the smoother the edges of metal, the higher the chance that a cold weld will take place.
Everything is cooler in space, even the welding. If you’ve been motivated to return to your latest welding project, don’t forget that we can provide you with all the welding equipment you could ever need, from safety to welding gas canisters. We can supply to hobbyists and tradesmen, so please contact us if you need more information.
