How to evaluate alcohol content in font solution?

[Tarun Chopra]

Hi,

Whenever fresh font is prepared the amount of alcohol can be verified with things like "alcoholometers" hydrometers without any additives like font solutions etc and the readings are very accurate, we can accurately estimate the amount of alcohol in water and then add font solution to specifications.

The problem which I am facing is the next day... when the font level in the chiller tank falls and when fresh additive is added how to verify the alcohol content in contaminated font solution? The hydrometer actually pops out completely?

I am being told by press operators that they have to add alcohol without measurement to avoid scumming during week days!!!

How do auto-dosage systems work? Do they keep on increasing alcohol dosage to avoid scumming during week days top-ups, is there a rule to this practice?

Thanks
Tarun Chopra

 

[spider]

Font solution and alcohol

Font solution and alcohol

I'll try and make it as simple as possible when you use alcohol with the font solution. your alcohol will attack the Font solution
when this happens the electric charge, decreases for your Font solution which gives you a low reading for your font solution
and then you will think you have to increase your solution in other words if you don't watch what you doing you will be caught up in a big circle. putting in alcohol then font and then more alcohol and so on

During the week when the press gets hot you will have to increase your alcohol depending on the temperatures

Auto-dosing systems for your alcohol use a hydrology and should keep it to the setting required around 5% or more,

I have found by keeping the font solution set correctly by taking a reading from where it enters the main tank and not from the tank itself.
And then tried to keep the Alcohol in the tank to 5%
And not from the same place.
I hope this is what you're looking for

 

[jbeniston]

In automatic systems "contaminated" dampening fluid returning from the press is flitered in the main tank. Some filtration systems such as "clean flow" remove almost all contaminants. The fluid is then passed through a system which, if you're using alcohol, checks the specific gravity, comparing it to a pre set value. If necessary the level of the float (hydrometer) will cause a solenoid valve to be opened, allowing alcohol to be injected into the fluid. The float will change level with the increase in alcohol and cause the alcohol flow to be switched off. Similar events take place to introduce additives into the fluid, as the system either measures pH or conductivity or demands the addition of "raw" water,
As the fluid is circulated to the press units and back to the tank, the dampening fluid is consumed, and the tank automatically maintains the pre set levels of alcohol, fountain concentrates, and water.
The press operator or the designated maintenance guy regularly check the contamination levels, either visually or by the change in conductivity and schedule the tank to be dumped, cleaned and refilled with fresh stuff.
Hope this helps a bit.

 

[RGPW17100]

Depending on how high tech your system is will depend on the accuracy of the alcohol in the fountain solution. Our chiller has a built in conductance meter and that is what we use to determine how much alcohol we need. As mentioned earlier by adding alcohol the conductance will go down. We maintain between 1100 and 1500 u mhos. When the conductance exceeds that is when we either have to start turning the water up or start scumming. Seems to me when using just a hydrometer you also have to take temperature into consideration. A 5 percent solution will be different at 70 degrees then it will at 65 degrees.

 

[lilgap84]

For new fountain solution, you could use the conductivity as a guide. However, as you print, the fountain solution will be contaminated.
The correct way that i have learned is to use an aerometer to measure the percentage of alcohol content.
Try asking your press chemical supplier, some carries them.

Jamie Choot

 

[Dan Roll]

Why are you using alcohol at all?

 

[Cornishpastythighs]

If you can, try and get off of Alcohol. Use a 2 part Fountain Solution( Etch and Alcohol sub) You can then measure your chemistry using Conductivity and a Refractometer to measure % of Alcohol sub. If you remove Alcohol from your pressroom you must ensure your press rollers are in good condition with correct Durometer specs, Rollers settings are checked regularly, correct printing squeezes and good dampening filtration and always follow the 3 golden rules, Minimum ink, Minimum water, Minimum pressure for good print. Good luck

 

[Tarun Chopra]

Thanks for all the inputs.

The reason for not using alcohol replacement solutions is that its very aggressive on thermal plates and we are getting strange problems running them including run length issues.

The problem which we are facing is to evaluate the content of alcohol in font solution during the week when the chiller is topped up and fresh font is not prepared.

Due to contamination of the font solution we are unable to accurately evaluate the alcohol content in the font solution because of which the press operator has to guess the amount of alcohol to be added during the week without any measurement.

Is there a way to identify alcohol content after font solution is contaminated using any measurement device?

Thanks
Tarun Chopra

 

[lilgap84]

might be the thing you are looking for.
http://www.boettcher.de/PDF-Dateien-engl/Araeometer-engl.pdf

 

[Tarun Chopra]

Hi,

Yes, but this does not work well when the font solution is contaminated. This shows very strange readings the entire thing pops out to zero percent due to contamination of font solution !!!

Thanks
Tarun Chopra

 

[Dan Roll]

Can you explain what your fountain solution is being contaminated with?

 

[Tarun Chopra]

Usually hydrometer gives correct readings when only water and alcohol is used. The readings change even if the font solution is added to this mixture of water and alcohol.

usually the chiller tank is contaminated with ink, paper fluff etc during press runs.

Thanks

 

[jbeniston]

Get a good filtration system and clean the solution. If it's so "polluted" that you cannot take accurate measurements you have other problems, like the reason for the excess contamination

 

[Dan Roll]

What temperature are you maintaining your fountain solution. Gravity readings are temperature sensitive.
Most contamination sources will not effect the specific gravity much, solvents will lower it, soluble salts will raise it. Non water soluble debris will have no effect. Do I read you correctly when you say that the hydrometer comes completely out of the solution? What range is your hydrometer?

 

[jbeniston]

Whose thermal plates are you using? Thousands of printers in North America have been successfully using alcohol substitutes for years and years on all kinds of plates including thermal, so what's the problem with yours?
If you want to run alcohol free get some help from the press manufacturer and your suppliers. Two of the things you will need is a good filtration system and good quality dosers for the fountain concentrate and alcohol suibstitute. You will never have to use a hydrometer again, measurements will only be made for pH and conductivity.

 

[jbeniston]

Do you have a problem with the hydrometer? Can you calibrate it? In raw water from the main, DI, Distilled or RO water it should read zero. Like wise in your standard correct mixture of fountain concentrate and water (no alcohol) only it should still read zero.

 

[lilgap84]

I've seen how the instrument works. It isn't as simple as directly reading the bar as directed on the contaminated fountain solution.
You also required to know the the density of your fountain solution together with a chemical drop test on your fountain solution to get the alcohol content of your fountain solution. The drop test counts the number of drops of a specific chemical when mixed to the fountain solution to become pinkish colour.
The aerometer that bottcher was advising me is the only correct way to read the % of alcohol content in the fountain solution ( especially on contaminated fountain solution); provided that the fountain solution is not dark in color where you would not be able to spot the pinkish appearance when doing the chemical test.

 

[Cornishpastythighs]

Sounds like you have other issues, invest in a good filtration system that thoroughly cleans the fountain solution removing all the 'stuff' that is contaminating it. Investigate what is contaminating it so badly that you cannot take reliable readings. Investigate why you cannot go Alcohol free and eliminate the issue as millions of other printers have with your type of plates. If the solution is getting so contaminated would'nt your conductivity climb through the roof.

 

[Tarun Chopra]

I've seen how the instrument works. It isn't as simple as directly reading the bar as directed on the contaminated fountain solution.
You also required to know the the density of your fountain solution together with a chemical drop test on your fountain solution to get the alcohol content of your fountain solution. The drop test counts the number of drops of a specific chemical when mixed to the fountain solution to become pinkish colour.
The aerometer that bottcher was advising me is the only correct way to read the % of alcohol content in the fountain solution ( especially on contaminated fountain solution); provided that the fountain solution is not dark in color where you would not be able to spot the pinkish appearance when doing the chemical test.

Thank you very much, got the point, will get in touch with bottcher to understand how to go about it.

Being a prepress service bureau asking my customers to install filteration systems is not a practical option neither they would convert themselves to go alcohol free.

The reason I wanted to know was that none of my customers know how much alcohol was going into the chiller tanks when they were topping up and not preparing fresh font solution.

Thanks
Tarun Chopra

 

[Cornishpastythighs]

Here's a simple tester I found lying around, maybe this would help. Works much the same way as checking the anti freeze in your radiator.