Make up a simple jig to hold the two ends, basically a bit of angle with slot in one web. Scarfe the ends of the blade on the grinder (mind your fingers). Hold the blade in the jig using a couple of clamps, with the joint over the slot, aligning the scarfe joins with flux & a snippet of silver solder in the joint. Heat up with a small gas torch till the solder runs then quickly clamp the scarfes together with a pair of pliers.
Reheat to just below the solder melting temp & cool slowly (I play the flame over it for a minute or so) to anneal the joint.
Works for me & the joints last longer than the original welded ones.
Mark