(ET) more on Leaf-collectors

All this talk of leaf collectors got me motivated to bump this project up on my list. Two weeks of rain helped justify an indoor project also. I found this "Giant-Vac" on craigslist a few years ago and was able to buy it for $75 without an engine. It was a pretty straight forward job to mount a snowblower motor and make a towbar for it. I had to find something in my shop to get the motor shaft up to 1''. I ended up using a 3/4'' copper pipe connector, sliced to go around the stepped key (impeller key is bigger than the one on the motor)and a little shim stock for a nice snug fit. I am not sure if the copper will be too soft over time so I drilled and tapped for 6 -5/16 nf set screws. Since everything is soaking wet I haven't had a chance to try it out yet but it sounds right and seems to be in balance. It draws around 65amps with no load. The intended use will be to harvest oak leaves to mix with crab waste and seaweed for compost. right now I use mostly coarse saw dust from a friends sawmill for brown material. Now I need a 5'' hose. Any ideas about what to use ? I will keep an eye on the plastic pile at our dump. Often 4'' or 6'' non perf flexible foundation drain shows up(we call it elephant guts) .