N-propyl alcohol versus Isopropanol alcohol

What is the fascination with alcohol? i haven't used it for close to 25 years. I also am a press operator. I have recommended products that I use every day and where I have acquired them.
This forum is supposed to be for disseminating information be it good or bad depending on your view point. If your are a user and you run across useful information and share that info with those who are experiencing troubles what is wrong with that. If your are a seller of consumables and don't have technology or technics to assist that is ok to state your view points of other technologies.
 
Green Printer said,
"This forum is supposed to be for disseminating information be it good or bad depending on your view point. If your are a user and you run across useful information and share that info with those who are experiencing troubles what is wrong with that. If your are a seller of consumables and don't have technology or technics to assist that is ok to state your view points of other technologies."

OK, but full disclosure of relationships with products should be presented. This is not always done.
A product could be great but if there is a lack of disclosure it affects the credibility of the comments.

I am sure everyone is interested in good products that one can believe in.
 
Often, when a complaint is isolated to the use of silvermaster plates the issue isn't so much the fountain solution or plate but the difference in the potential for transfer these plates present. While the background of silver master plates gets a lot of attention, the silver halide image areas are usually the problem. The image area on these plates is not as ink receptive as the images on other plates and if the ink is not adequately liquid on the form rollers, the plate will not take ink from the rollers efficiently. Big presses have lots of roller surface area and lots of roller to roller contact that mills the ink while the press is running into a fairly liquid state. On a small press where this friction is smaller in comparison, alcohol often served the purpose of making the ink more liquid. Without alcohol, the ink may need reducing with varnish or linseed oil in order to run properly. At the company I worked for prior to where I am now, we printed the product labels on a beat-up old 1250 with a Crestline dampener and Silvermaster plates for well over ten years. Customers would routinely send me ink they said would not run in their operation, but we never got any ink we were unable to use printing our labels. Some of these inks required reduction and others did not, but I do not remember ever actually buying any ink for that operation. Of course we ran without IPA, running a one-step product currently available from several vendors.
 
Hello Dan,

I may try reducing our ink, although we don't have any problems with any of our other water systems - I've got conventional integrated, Crestline, Kompac and motorized. I'm only having problem with the 385, which is my only press with this type of dampener. I'm not having problems with the image - it is dark enough, and for 400 copies the quality is great. Then slowly the plate inks up, starting at both outside edges.

I'm going to try some ethanol, and also reducing the ink a bit with linseed oil - but thin inks have been a disaster in our other duplicators - they like it thick like tar!!!

Thanks again for the ideas.

Alois - yep, too LOW of levels for the alcohol! This is what cheap substitutes do.... :-)

BG
 
Here are the pdfs Alois is trying to show us. There should be 2. Maybe I am loosing my touch also?

@Cory: There is a problem with the posting software. I I try to edit my post, there are already 2 pdfs showing, but as you can see her, only one comes through.

Al
 

Attachments

Last edited:
One issue I found with most alcohol free founts is they are designed around a metal plate and struggle to keep the poly plate moist especially when you start running uncoated stocks, you then erroneously turn up your water dials, which then leads to the need of increased ink dials and soon you on a downward spiral.

Second issue is some manufactures have then decided to add even more glycols, or glycerin etc for the poly plate which then give you other issues. The glycols attack the ink & plate along with forcing you to have to run a thicker ink film to achieve density. Then the final kick in the pants is the fact that both glycols and glycerin have a dramatic effect on the inks ability to set & dry.

With the WDP+HR a fount that is designed to work well with poly plates without the use of the above chemicals we are currently seeing cost savings from the following:
Zero alcohol
No need for de-ionised or RO water anymore
IR dryer hasn't been turned on as we now have faster drying then what we ever did
Ink keys & sweep have been reduced
Fount tank water is staying clean so no need to dump it all the time = less waste to be shipped away
Plates lasting longer

De-ionised water was $25 a 20L drum
IPA was $85 a 20L drum
Waste liquid pickup is $35 a 20L drum
IR unit uses a lot of power then you have the added heat in the pressroom the aircon has to try dissipate.

You do the Math....
 
Al Ferrari said:
Here are the pdfs Alois is trying to show us. There should be 2. Maybe I am loosing my touch also?

@Cory: There is a problem with the posting software. I I try to edit my post, there are already 2 pdfs showing, but as you can see her, only one comes through.

Al
Click to expand...
Al, great article thanks for the link would be interested in the 2nd pdf if you can upload it
 
We can thank Alois for it. He emailed it to me and I in turn posted it. As you can see from my comment to Cory, the other one didn't load for some reason. I'll try it here now.

Al

The pdf does not want to attach. There may be some sort of protection added to it.
 

Attachments

Last edited:
It is common for printers to confuse viscosity, specific gravity, surface tension, and other physical properties of liquids as exampled above. The relationship of volume to weight (specific gravity) was used to meter alcohol into fountain solution circulators because the difference between the gravity of IPA, being .79, and fountain solution, being some minor value above 1.0, allowed reasonably accurate alcohol metering if enough alcohol was used. The old style 'balcontrol' type units were not very accurate at dosage levels much below ten percent.
Viscosity of liquids is essentially resistance to flow and is measured with a variety of instruments, all of which have advantages or disadvantages depending on the type of work being done. Alcohol increases the viscosity of water significantly, and this is easily demonstrated by any viscosity measurement method.
Surface tension is a complicated subject. Rather than thinking of making water wetter, as most printers envision it working, it would be better to think of surface tension indicating in some way the potential of a liquid for wetting a surface.
The belief that alcohol works in fountain solution by reducing surface tension is based on observations so obvious it is almost impossible to convince press operators it is false. It is this belief that makes alcohol free printing so difficult for some people.
 
Hi CostaRicaPrinter,

While I am only suggesting you try reducing the ink on this particular press, I am not endorsing thin ink in general. This has nothing to do with the press or the dampening system used, just the use of silver halide image plates. The idea that the press 'puts' in onto the plate is widely held, but untrue. The press is only making ink available to the plate and the image area is required to remove ink from the rollers and present it to the blanket. With silver plates, the ability of the image to pull ink from the rollers is not very great and often reducing the ink will improve the transfer well enough to prevent problems from occurring. If the plate is not efficiently removing ink from the rollers, the poor pressman is forced to make more ink available, then forced to run more water, then forced to deal with an unstable ink/water balance, then forced to deal with ink that gradually loses its litho properties.
Of course, you may be looking at some other problem altogether. Diagnosing print problems from a distance has its limitations.
 
Dan Roll said,

"With silver plates, the ability of the image to pull ink from the rollers is not very great and often reducing the ink will improve the transfer well enough to prevent problems from occurring. If the plate is not efficiently removing ink from the rollers, the poor pressman is forced to make more ink available, then forced to run more water, then forced to deal with an unstable ink/water balance, then forced to deal with ink that gradually loses its litho properties."

The use of poly plates or other low cost plate material has interesting potential.

The present testing of my technology to make print density consistent is running on a press with UV inks and alcohol free fountain solution. Actually the first test that was done in 1991 was also on a press with EB inks and alcohol free fs. Alcohol free fountain solution does not seem to be a problem.

At some time in the future, it would be interesting to have tests done on a press with poly plates to see how it performs. I suspect there could be a nice benefit with running the less costly plates with a process that is under control. That would be nice to test with interesting potential.
 
Back to n-propyl alcohol for a moment, regardless of the various claims made for this products virtues/vices, it is flammable. Any fountain solution sold in the US containing one percent or more of this material would require a flammable label. The rest of the world (where government regulation either makes more sense or has not run as rampant as in the US) sees plenty of fountain solutions containing IPA, ethanol, n-propyl alcohol, and other flammable ingredients sold without restriction.
One of the many benefits of running an actual alcohol replacement fountain solution is the elimination of the fire potential of having alcohol around your machinery.
 
Dan Roll said:
Back to n-propyl alcohol for a moment, regardless of the various claims made for this products virtues/vices, it is flammable. Any fountain solution sold in the US containing one percent or more of this material would require a flammable label. The rest of the world (where government regulation either makes more sense or has not run as rampant as in the US) sees plenty of fountain solutions containing IPA, ethanol, n-propyl alcohol, and other flammable ingredients sold without restriction.
One of the many benefits of running an actual alcohol replacement fountain solution is the elimination of the fire potential of having alcohol around your machinery.
Click to expand...

Dan what do you recommend for alcohol replacement?
 
Green Printer said:
Dan what do you recommend for alcohol replacement?
Click to expand...

As I formulate and sell fountain solution for a living I have a preference for my own products, but this is not an appropriate forum for flogging one's own wares. That said, just about everyone who makes fountain solution makes a product that will serve, the controlling factors in choosing a product are more what dampening system your press is equipped with than anything else.
The successful use of alcohol replacement chemistry is easier with an understanding of the basics of how running alcohol in continuous systems differs from not running alcohol. The short version is when you run alcohol, several things conspire to convince you that you are running less water than when you do not run alcohol. This is usually based on the difference in dampener 'dial speed' (lower with, higher without) being considered to represent how much water is being consumed. This is misleading in the extreme and is easy to compare. Try turning off the supply to the dampening tray and running until the pan roller loses contact with the solution. You will print considerably more impressions before running out of water when running without alcohol than with it. This is the viscosity property at work. Most of the problems pressmen encounter when first running alcohol free are associated with attempts to not run what looks to them as inordinately high water levels when they are in fact not running enough. Light roller pressures and running a scum/washout cycle (turning the water down until the plate scums and then turning the water up until the image washes out, then running somewhere close to the midpoint) usually will set things right.
Pressmen that are afraid of the chemicals used in alcohol replacement products will find them in common household products and cleaners. The volumes of glycol ethers used in these products are modest and in the mixed solution, quite small. For the overly concerned, avoiding physical contact with these products just involves not touching the concentrates, the glycol ethers used are not volatile enough to be an inhalation hazzard unless you were to heat them to their boiling points.
 
You must log in or register to reply here.
   
Back
Top