Uponor PEX ring problem

[chiraldude]

I recently bought a manual Uponor PEX expander tool and used it today to replace some pipes. I really love the plastic ring system but there was a particular problem when using the expander.
What happened was that 2 out of the 20 rings failed to stay put when expanding the pipe. They started slipping after the second or third pull and then just shot up the pipe. Had to cut a couple of inches off and start over with a new ring.
Is this a common occurrence or was I doing something wrong?

 

[Matt30]

The white rings have a stop to keep the pipe back 1/8" from coming through the ring. The coloured rings don't have this. The 1/8" is to allow for a little slippage.

Remember to rotate your expander in between pumps.

 

[chiraldude]

I am using the white rings with stops. The stops are only good for keeping the user from pushing the ring on too far. I can easily push them past the stops so they won't prevent the ring from moving during expansion. The rings do have the Uponor logo printed on them.
In one case the tubing was wet due to water coming through the existing pipe. I wonder if being wet made it slick?

 

[Matt30]

The fact it was wet could be a factor. Beyond that im a bit stumped. I have tens of thousands of the white rings installed out there and i havent ever had one slip. The white and blue ones slip on me once in a while but never right off the pipe or to the point it couldnt be used

 

[Mike Richardson]

I hold the collars with my hand so they dont slip up the pipe. If they get wet this becomes a problem. But I expand with my Milwaukee and never used a hand expander.