For pump impellers. I believe that this subject may have been touched upon briefly before, but I guess that I am interested in everyones opinion on which is the best pump impeller material type for the money? I have a couple of the following pumps and one of them is in need of a rebuild. http://www.wwpp.com/products/flint-and-walling-pumps/cjrepairparts.pdf The pumps are Flint and Walling 2 horse 3 stage pumps and they came with brass impellers. The pump in question was torn down 2 years ago and I had a machine shop build up the impellers and I replaced the wear rings, it needs it again and this time I think I will replace the brass impellers, but there are 3 impellers and they cost about $125 each, with the rest of the stuff that brings the price of the rebuild to a little more than $500. Plastic impellers are less than half of the cost of brass and the performance is the same. I'm sure that they wouldn't last as long as the wear rings would still be brass, maybe the wear rings would last longer - that would be a good thing. I am concerned that the plastic impeller may wear out really fast and require much more frequent maintenance and in that case the savings may not be worth the hassle, but I am very interested in others thoughts and experience on this subject.