soldering and water in pipes

[Dave2010]

hey guys.

I know this can't be done and I am sick of coming across isolating valves that pass preventing me from soldering. I have heard of the old bread trick but not tried as yet but I have recently come across this

anybody tried or know of them?
You stick them in and when finished, heat the area they are in and the wax melts

 

[Fluffster]

So when the water cools down again it returns to a solid state and becomes an obstruction or even better it clings on to a flow switch or sensor.

I would not be tempted in using unless I could remove it totally straight after soldering.

Pete

 

[Dave2010]

I would have thought flushing the pipework would clear it as it has melted?