This is one of those times when you'll probably spend more cash trying to get the blade repaired than it is worth. The TIG idea is somewhat risky, but might work. I do know of people that have spot welded cracks in axe heads in an effort to save a tool. Some of the welders can screw up a blade by trying to fix it. Welding is really an art in itself. I once used a machete that had three cracks in the blade. That knife was used hard for over a year before the 3-4 mm cracks actually compromised the blade. If you do elect to have the blade welded, select an artist who knows his way around a welding shop with plenty of 'burn-time' under his belt.