eXraycer

I scored about 60 meters of 40mm PVC pipe for Free from my brother who is a plumber, also found that 40mm copper pipe fits neatly inside so I can make short dowels with that which will fit snug. (Copper pipe was free too but you don't need much, the connector dowels I cut were 150mm long).

Also, I went to the hardware and bought 30meters of flexible drainage pipe for about $30. It's 50mm diameter which allows you to make the long radius bends for the fast sweepers. The copper pipe dowels fit inside perfect to connect it. As it has ridges you can cut the flex pipe in the low spot for a more flush connection that won't rip apart your bodies when you impact it.

Now just gotta make some plugs to fill the pipes with sand.

eXraycer

So far so Good.
Cut the pipes to 3m each then plugged one end with filler foam spray and once dry I filled with raw plastic pellets then plugged the other end. Note: I left the plugs 4inches shy of the ends of the pipe so I could insert the connector dowels. Was going to use sand filler for weight but plastic pellets were handy cause the factory seen in the pics just happens to be a blow moulding facility. In hidsight, sand would have been heavier so maybe a tad better but he plastic pellets were easier for me. Takes 10 minutes to put the track together you see here and we can change the shape quite easily which we probably will do to remove some of the snags around the track like that 45degree bend at the top of the pic we might replace with the flex pipe you see to the right of that cause the flex pipe really doesn't need to be on an outside bend. It works much better on the inside of a bend cause those sharp corners at higher speeds can savage the body and snap servos.