Any rod material the same diameter and length will make a temp. shear pin.
Downside is that the material used, could be of a shear strength higher than the prop housing. Emergency use, yeah, but being the cheap (frugal) sob that I am, I found out that welding rod was not a wise decision on a 2hp. suzuki, as a shear pin. Tried what I thought would be the softest brass rod, and it worked fine till the prop hit something, and the hub of the prop broke out and only bent the "shear pin". I know you are talking about a TM, but be careful of using a material that could be possibly be of a higher strength. It's supposed to be the weak link. Carry a spare prop.
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