well ,after another 8 hours of welding, it broke again. Making this the fourth time one blade broke off the 3 blade impeller. In hope of help, I explain how I did it the 4th time. First I sanded the parts and tried to keep touching them to a minimum. I coated all the parts in flux and let that dry. Then I set my part in this rig I made. It makes it possible to weld are three blades on at once, in their proper finished position. Okay, so I this time I thought, was it. I carefully put everything in the jig, all metal touching, all fluxed. I heat the whole rig evenly with my propane torch for maybe 30 seconds, till the solder would melt on a blade and the shaft. I get all three done cool it down immediately with water and it seems fine, I started by trying to rip the blades off, sounds bad, but it the weld is good, it's obvious. they all pass the test. So I radiused, the impeller balanced, and then ............... then I'm sharpening the blades and this one blade bends while aparpening it with the grinding wheel(holding with hand).

Ok, lets see if there a problem I put it in water first then try to bend that blade carefully by hand. Immediately it breaks off......and honestly at this point 18 hours of fabrication time, I gave up I just had too, the other two blades are solid and they were the ones that have been solid. I 'm very confused, it's not like it bends bends and breaks, one bend and it breaks. btw I had even made a new blade. In case my rambling is unclear I have had this one blade fall off 4 times, the other always cooled with a good weld even after 4 times, since all the blades come off when I heat the impeller. I've changed the blades, the shaft and still these two original blades always hold and the third breaks. The solder tends to look aerated, like a cold weld, but it wasnt a cold weld. I'm only describing it ridiculouslly in hopes someone knows what I'm doing wrong.

Any ideas?
I'm going nuts. I'll add pics off this rig I made and the 4th gen impeller that was ready to install when it broke.
If you need the pic, theyll be up in like 30min.