Fountain Solution

[Davis.zhou]

We check the conductivity, pH, temp. and IPA content of fountain solution every day. The new fountain solution parameters is;
conductivity - around 900us to 1000us,
pH - around 5.0 to 5.2,
temp. - around 9 to 10 degree C
and IPA - 9% to 10%
All above are quite stable and within the range expect the conductivity is keep on increasing everyday, but the increasing is very small.
We are in 24 hours working, The fountain supplier suggest us to replace the fountain every 7 days no matter how is the parameter is.
In general, the conductivity of fountain solution before replacing the new fountain would be around 1100us and we never experience the conductivity over 1200us.
I just wondering if all parameters - conductivity, pH, temp. and IPA are so stable, why the supplier still recommend to replace the fountain every days. They stated that if the working hour is 8 hours a day and 5 days work, then the fountain need to replace every two weeks.
Anyone providing a recommendation on this is appreciated.

 

[Cornishpastythighs]

The fountain solution picks up a lot of 'stuff' during its working life and thats what changes the Conductivity. Stock, ink, roller and blanket wash all contribute to the conductivity number you see during the week. If you have excessive ink feedback onto your metering rollerds and the operators are using solvent to clean the ink off this is all going back into your FS tanks and raising the conductivity.
The fountain solution supplier has a vested interest in you changing the solution every 2 days but I think that is excessive. For good quality litho I would monitor every day and change once per week, dont forget to change the filters also.

 

[duct maestro]

So what are you dosing your fount at then? What machine are you speaking of? Alcohol is very high!