Does the pitch change over time?

[Gforce]

Does anyone know if the pitch of the impeller will change over time from normal use? I only ask cause one of my customers is into cryo-treating metal and he thinks that the treatment on an impeller will make it harder overall keeping it from losing pitch and resisting any abrasion. I figure for $25 I'd give it a try the next time that I get a new impeller but was wondering if it's even a problem that people see.

[UFO-RXT]

I guess the pitch could change over time it can surely be changed by damage and just normal use. I think I would be very skeptical of any claim to be able to make it harder to stop normal use changes of an impeller.

[Green Hulk]

I have run the same pitch on my prop for a long time with no change in pitch.

[RX951]

It should never change unless a tanglible object physically came into contact with it...
ie.) rock, ect....

[jawz]

The cryotreating takes the stresses out of the metal... I think it would be a great idea AFTER you get the pitch right(especially on the 3-blade).

[way2fast]

All metal, especially the soft low grade SS used in props, has a "memory" and will have a tendency to return back to it's original configuration..ie ...pitch. This is one of the reasons radical pitch changes are not recommended from stock. A slight bend change probably won't noticably be affected with use, though.

Richard