I was lucky enough to buy a 10 round tropical tin Kynoch container for my .318 Westley the other day. It was of course opened but I was wondering how they put the lead on around the edges.

Was the container empty as well?

Yes, luckily. As ammo cannot be shipped to Alaska except by boat.

Soldering tin is easy to do. It just takes some heat to melt the lead.

Instead of an open flame(which would be a little scarey),they would have used a heavy copper soldering "iron",which would be heated then used to transfer heat to the joint w/o flames.
Mike