When done well, welding allows making rings with small seamless and strong connections. However, welding rings tends to be more difficult and costly than other methods.
The oldest method of welding is forge welding. It is also the only welding method available to ancient mail armour producers. Forge welding of rings is performed like this:
- Create a ring with overlapping ends
- Heat it beyond a critical temperature
- Strike the overlapping area with a hammer
Forge welding bears some challenges that are even more difficult to overcome for small rings:
- Temperature: The critical temperature for iron is reached when it is glowing in white-hot colour. Steel should be glowing in bright yellow. There is also a chance for rings to be overheated. That is visible by the metal shedding sparks. Overheated rings are brittle and have a poor connection.
- Time: Smaller objects adjust faster to ambient temperatures. Therefore welding of chainmail rings needs to be performed very quickly. Rings need to be hammered within few seconds after they leave the oven.
- Oxidation: At high temperatures, the iron creates a brittle oxidation layer on the outside. This layer is an obstacle to a good connection. The metal needs to be stopped from creating the oxidation layer by covering it with a substance that is a liquid at high temperatures. This substance is called flux. Some sorts of sand can act as a flux. Modern blacksmiths also use borax. When the welding connection is made, the flux needs to be squeezed to the outside to leave. This is done by starting to strike the joint on one side and incrementally moving to another.
Despite difficulties forge welding can be done with small rings. However it is best done on rings that are not yet interlinked with others. Welding interlinked rings requieres the whole piece of mail to get close to the heat source. This adds a high chance of destroying rings. To avoid this, welded rings can be closed before interlinking and used in combination with riveted rings.
Today rings can be welded by electrical pulse arc. The method uses an electric current to strike an arc between two electrodes. Search for