I have had plans to try to Tig my broken blades as an experiment but have not yet tried it.
On a welding forum that I belong to there has been the discussion about this and it tends to go round and round about the brittleness factor if the blade is not dealt with during the cool down properly. Most folks have said that it is easier to take them to someone that has the correct equipment for welding blades and pay them to do it to ensure that it is done correctly. Alignment, heat treatment and grinding the weld smooth are the issue that you have to deal with.
I still plan to try it but have not yet and if you have don't have a good set of TIG skills I would think the risk level of purchasing blades and then experimenting might not be worth it.
If you have the time before the blades get sold to someone else, take some of your broken blades and try it.
If you get a good result them maybe, if not you will know.
Look around and see if any shops can do it at a good price.
