Re: Welding on or repairing a prop?
I can't count how many I've done that way, on a smaller motor, there's not much noticeable difference in the metals. On a larger motor that makes more power, it may be a bigger concern. The bottom line is that its far better off than it was with the chunk out of it.
I rarely send a prop out for repair, if a prop is bad enough that it needs to be sent out repair, it's most likely going to need a new hub as well, so the cost of a new hub plus the $39 flat rate repair makes for an $80 plus trip to the prop shop, plus shipping. I've bought new props for less than that on eBay.
I have taken junk props and used them for parts, often cutting off a blade from a badly damaged prop and affixing it to replace a damaged blade on a better prop. The good thing about aluminum is that it welds well, but it does show signs of softening or weakening when you weld. The proper procedure is to re anneal the whole prop in an oven but I rarely do, and I'd venture to guess that many prop shops don't either. What it boils down to is that the weld often can cool faster than any hydrogen introduced in the welding process due to contaminants or humidity can harden or make the welded metal brittle.
I have an old 5 hp Sear Gamefisher motor on which I gas welded a new blade to the old two blade aluminum prop many years ago long before I could afford a proper welder. Its been fine ever since even though it's hit its fair share of stumps over the years.
