When making this type of chains don't we need to solder jump ring
by jump ring.
It would be very nice to solder them all, but the force is
distributed among all the jump rings evenly and they are not pulled
enough to open. Also, the rings are half hard when starting and many
people tumble the finished chain which hardens them further.
Soldering would anneal them and then they could distort with force.
The way they are made, the rings do not even distort. There is a lot
of on this on the Urban Maille website
The few rings near the clasp can have disproportionate force on them,
and therefore I (and others) do solder those.