Fear of damaging press– seeking advice

We have an SP20 and an 18 x 24″ magnetic base. We recently ran a job that required a full flood (with only minor knockouts), flood size 15.5 x 17.5″ We were attempting to minimize the saltiness of the print, so we upped the packing and the ink. Does anyone have guidelines to follow in regards to how much is too much to ask of a press? What do we risk by running such a large flood with heavy packing?  Can we throw the bearings off? Damage the underrails? We love to do unusual and difficult jobs, but we want to keep our equipment in top condition. Any advice or information is much appreciated!

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Eric Holub
Editor
12 years ago

Thanks for putting this in context jhenry. In my work I’ve never needed more than a spot-varnish. I guess I’ve seen “floodcoat” in more recent trade magazines. Coating is a specialty slightly removed from printing even if it might use the same equipment. One of my teachers tried to convert a Chief 22 for aqueous coating just before SF dot-com rents forced him to close shop. Then he gave me all his reference materials, and that’s why I spend so much time thinking about the differences between practices when I learned on the floor, and what happens now online.
Different worlds.

John Henry
Editor
12 years ago

Sorry to be a bit late to the discussion.

While I have not been able to discover a reference source in antiquity (today that means over 30 years ago) for the term “Flood”, I do remember, from my years of stripping negatives and positives for litho printing in upstate New York, the term was used to denote an uninterrupted full coverage of ink with no image areas dropped out. It was generally used for a gloss varnish coat with full coverage. Some printers would simply pull the water form rollers and run the varnish on an old plate, but that was abit messy, and most higher quality shops wanted a separate plate made with register marks to match the image plates.

I still use that terminology in our current production setting, and everyone seems to know what I am talking about.

John Henry

Gerald Lange
12 years ago

Rachel

I was wondering if you are using a Patmag or similar?

The piece I pointed out was actually a magnesium plate. It would have printed a lot easier with a photopolymer plate, that is to say, we would not have had to expend so much energy to get it to where we wanted it, except for if the incised areas began to pick up ink. Photopolymer is a major pain if it has to be cleaned during a run. The relief is as tacky as the surface and likes to gather paper dust, lint, ink and solvent residue. A concoction best avoided.

http://bielerpressxi.blogspot.com/2006/03/photopolymer-plate-longevity-post-in.html

There is a solvent and brush specifically made to address this problem, which I have used: (there are a number of products listed on this website)

http://www.flexocleaners.com/Flexo-Ink-Cleaners/Plate-Cleaners/Strong-&-Safe-Photopolymer-Plate-Cleaner/

Maybe this info will help a bit?

Gerald
http://BielerPress.blogspot.com

Eric Holub
Editor
12 years ago

Two things: first, don’t think I am objecting to the term flood, just trying to find its origin. As I said, never heard it until a few years ago, been printing almost 40 years in SF and trained by printers and lithographers apprenticed in the ’40s and ’50s, all in SF too. So I am still wondering if flood is a regional or colloquial term, or is specific to LP pressmen or something else. I don’t remember seeing it in any prepress text and a reverse is a prepress creation.
Second, as for printing full-size solids on textured stock, realize that if the plate is metal or hard photopolymer, you need enough pressure to conform the paper to the plate (and that is more than a SP-20 can do dry) and enough ink to fill any voids (full coverage needs continual replenishment, though ink needs would be reduced if printed damp) . Add a reverse and if it isn’t suited to the paper and ink, it may well fill. There is a reason why offset replaced direct lithography, and that is because soft rubber conforms to even rough stock with a minimum of pressure. And for the same reason, printing solids is easier from a softer durometer of photopolymer, or better, a rubber plate if you can find one. You won’t get any visible impression, but you will get smoother ink transfer.

Gerald Lange
12 years ago

Thanks Paul. There are commercial grade cover stocks that can be dampened without cockling and will lie flat on the cylinder. Few and far between though. Curtis Flannel Cover is great, but no longer made. The main problem with most commercial grade papers is the severe grain direction. When dampened, this can really throw the registration off.

Gerald

Paul Moxon, Moderator
Admin
12 years ago

Beautifully done, Gerald.

Less experienced printers are advised that dampening does make all the difference for mouldmade and handmade paper, but that they should not dampening commercial papers. These will not lay flat on the cylinder and desopite every effort to dry under pressure will cockle and wrinkle.

Gerald Lange
12 years ago

Oh yeah. Dampened paper as well. That is the first step.

Gerald

Gerald Lange
12 years ago

Rachel

Don’t push the press beyond its limits to do what certain inks and inking practices can provide.

http://www.flickr.com/photos/bielerpress/74886352/

On this piece we used Charbonnel ink with the Setswell Compound on a smooth mouldmade paper. We tripped a bunch and double printed etc. And cleaned the plate constantly to retain the tiny detail. We got a solid black without picks, etc., and held the detail on the incising. This can be done normatively without screwing with the impression to compensate.

Gerald
http://BielerPress.blogspot.com

Widmark
12 years ago

in my limited experience, I’ve heard the term flood used by designers to describe a full flat printing of a color, in the context of offset printing usually. Perhaps the term did originate with silkscreen, where you often “flood” the screen by pulling the ink across the screen prior to the print stroke.

Eric Holub
Editor
12 years ago

I had an SP-20 for ten years. It simply is not strong enough to to do full size solids on textured uncoated paper, but is adequate if you are doing a kiss impression on the news or coated stock it was designed to print. If you need punch, dampening cotton stock will help but don’t expect full impression or ink coverage even with double-rolling, and even then not all stocks will work. It is a proof press, not a production press, and heavy impression use will wear it out. You can most definitely wear the under rails and the bearings.
I’m curious about the term “flood”. Never heard it used by any letterpress printer or lithographer in the western US, or seen it in any LP or OS printing text anywhere. (First time I heard the word in a printing context, it was from a printer who trained as a chef). In printing, we talk about solids and reverses, and the original post describes a standard reverse. But the economics of recent years have drawn in both lithographers and distantly-related screeners to letterpress work, and many designers untrained in the the printing trade as well, and the standard terminology has been affected.

Gerald Lange
12 years ago

As said, dampening will help quite a bit, and double inking, and correct paper. So will ink additives such as Setswell Compound. No need to push the press beyond normal stresses to achieve this.

Gerald
http://BielerPress.blogspot.com

Widmark
12 years ago

People say great things about dampening?

Paul Moxon, Moderator
Admin
12 years ago

You’ve answered your own questions. You’re stressing the bearings if it takes extra effort to roll the carriage over the form.

If heavy coverage is required you could try double-inking or use a different paper that asborbs less ink.

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