Fastest/cheapest/easiest is as follows.
-Go to Home Depot or any store that sells plumbing supplies. You should be able to buy like a 10' galvanized steel pipe. You want it to have a 1.5" inner diameter (which will be a 1.9" outer diameter).
-Have them cut it at 2.5'. You now will have a 7.5' pipe and a 2.5' pipe.
-Take a roll of gorilla tape, measure about 11' from the end of the 2.5' pipe, and just wrap the tape around it over and over until you've build up a substantial bulk. Do this on both ends.
-You've now built a thick handle plate loadable dumbbell. Use pony clamps or locking collars to hold the weights on.
-With that 7.5' pipe, do the same thing with the gorilla tape. You now have a fat grip barbell/axle. This all cost you like $60.
In this thread, I make a circus dumbbell using a similar procedure. You won't need the home depot buckets to pull it off though.