Toolman
Well-Known Member
- Joined
- Aug 19, 2014
- Messages
- 472
- Reaction score
- 741
I used to weld a lot of these impellers before Covid hit. There are used in Canada, New Zealand, and United States in River racing. I believe the boats are aluminum hulls. These guys will hit 131 mph going upstream. Sometimes the water is shallow as 1 foot. These impellers are made of steel and get damaged severely during racing. They suck up sand, rocks, tree branches etc. The center veins is a separate peace from the outer ring. Before the welding is done, the veins are hand chamfered with a 1/8 inch edge break to give the weld a lot deeper penetration. I weld both sides of the veins and from the side you can see the heat trail. The welding rod is real soft to allow the veins to flex without cracking the weld. After the welding is done, the impeller goes back into the lathe and gets skimmed in the area where the magic marker drew a line to get the impeller around again for a good seal. Depending on the horsepower, that area gets skimmed down more to allow more flexing without ripping the seal out. The more horsepower, the bigger the gap. This is not a pretty, tiny precision weld. This weld has to have a lot of filler rod put in and I’ve got the pedal down on my 350 amp TIG welder and I’m using about 260 of those amps. The filler rod is 1/8 inch diameter and it flows into that valley really fast.
Last edited:
