hey guys. k so we have been doing lots of line pours lately and looking from the fellow pumpers on how they make a prime for lets say 200 feet + of mixed steel and rubber. 

1yd of grout never fails 

ive heard some fellow pumpers say put a ball ahead of your prime or a wadded up crete bag 

Not every grout is the same. Quality of sand can vary from place to place.

The real golden way to prime is pure cement/water mix. Put bal wraped in plastic in line (not to tight) than some water, another bal and then the mix. half a m3 cement water is enought for 1000'

Important that the cementwater is not mixed to thin.  Should be at least as stiff as thick yoghurt. And use loads of retarder in it. We use 10L per m3.

Disadvantage is that you have to throw away the primer so if you mannage with grout and you can use it in the poor than I would do that.  But if you have a job where you realy can not plug up this is a great way. (IMO)

The system with the balls ahead doesn't work with grout (if the grout contains quite large sand particals.) There its better not to use the balls becaus then the grout will kind of roll forward refreshing the first bit of grout going ahead in the pipes.

Portland and water works good for me. but I always prefer grout with a little water ahead

ok thats help here is the kicker are you guys using the ball catcher port or hopper mixing as our one truck does not have this port

I mix right in hopper with the rake that comes with pump

Small amounts I use the primeport. Medium I fill up the prime port and a bit in the hopper. Huge line jobs I get it from the factory and put it in the hopper. Pump untill I filled about 30m line and then the normal concrete. Great results