I am obtaining poor results when roller tinning?

It is essential that the Printed circuit board to be roller tinned has had the required pre cleaning and fluxing operations.  The top roller pressure needs to be correctly adjusted to give the correct level of thermal conductivity between the bottom roller and the copper and that the roller speed is set correctly.  Poor roller tinning can also be caused by two much Flux on the PCB or the Tinning Salts need changing.