Is there Letterpress polymer plates that can be used with water based ink?

Polymer plates can be used on letterpress machines, they were mainly used on rotary letterpress machines and are quite usable on Heidleberg cylinders and platens. Wash up with tap water. Do not use oil based inks as the polymer will react and melt.

the question is if you can use water-based inks. That, I don’t know the answer to.

However, you can absolutely use oil-base inks and polymer. I do so exclusively.

The nylon based polymer that used to be manufactured by B.A.S.F. in Germany was definitely Ok with oil based. Still sold? I dont know. But I do know that a number of different polymers were available to blockmakers, metal backed and so forth, and the developer solutions were greatly different. .

Maybe rroddi is thinking of solvent-wash photopolymer material, which would be suitable for use with water base ink. Most of us are using oil-base ink on water-wash photopolymer with no problems. I don’t know any letterpress printer using solvent-wash plates, but there might be platemakers somewhere who could provide them.

Parallel_ impression, you are probably correct about polymer, I have not used it for general jobbing work, only overprinting envelopes and similar cheap commercial work. Any quality work was done with oil based inks and metal plates, lead type and a new type of plastic which was not all that good. 23 years ago I washed up my last ink knives, and said goodbye to dirty fingernails and started collecting my aged pension.

Harrild
http://www.kayedee.co.uk/printingplates.htm?gclid=EAIaIQobChMIxabB4prA1w...

yes water and solvent based
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“
Liquid Photopolymer Products
MacDermid Graphics Solutions’ broad line of liquid photopolymer products offers an unbeatable combination of exceptional value and quality to the flexographic printer. Liquid Platemaking is well suited for the following water-based ink printing applications: corrugated post-print, wide web/thin plate and hand stamp/marking devices. Using liquid platemaking in your operation has a significant number of environmental advantages as well.”

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hhmm lots interesting stuff here
http://graphics.macdermid.com/products-and-services/packaging-plates/dig...
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Flint do the nyloprint

http://www.flintgrp.com/en/products/flexographic-products/nyloprint/

cheers

I forgot about liquid photopolymer (it’s a detergent wash process). At the high end it is used in flexo (Merigraph is one brand), but at the low end it’s sometimes sold through rubber stamp suppliers, and I’ve seen it on eBay too.
My Ludlow photopolymer exposure unit can expose both liquid and sheet material but I’ve never tried the liquid.

To parallel: I have a Ludlow photopolymer unit I’ve used for years to make Liquid Photo Polymer Rubber Stamps. I have two metal backed “hard” polymer plates I would like to make letterpress plates with. Could you give me some sample exposure times on the Ludlow you use? I put together a convection oven to cure the plates before final post exposure in the bottom tray of the Ludlow…

Gil, exposure time will vary with material type (and thickness) and the condition of your UV lights (they weaken over time). The best thing to do is get a platemaker’s 21-step Stouffer’s gray scale, do a test exposure and adjust until you are at manufacturer’s specs (which also vary).
Seat-of-the-pants, try 3 or 3.5 minutes, and adjust.
Maybe a convection oven will work, but a static oven will not. It isn’t just heat, it is heated air carrying away moisture. Leave the door ajar? I settled on using a small fan-heater blowing through a coffee can tube (plates stuck inside on galley magnets) until I got a proper all-in-one unit.

Thank you parallel for the info. I have a Stouffer scale. My oven is a $30 Black & Decker toaster convection oven - the smallest I could find. I think I’ll put a small fan next to it and leave the oven door ajar and set it on “warm” - no higher than 190 degrees for 40 minutes. I like your “galley magnet” suggestion too. Home Depot sells these on their magnet display. I also have a Polymer Plate Shear for cutting the plates - any comment here?

Well, when I tried using a fan pointed at the toaster oven, door slightly ajar, the top front heating element failed fairly soon. Then I moved plates in front of the forced air heating duct in the shop, which works, but is no fun in warm weather. Eventually I settled on the small fan-heater as most efficient.
I cut plates on a 24” Milton Bradley cutter, and the most important thing is, use a damp rag to remove photopolymer buildup on the blade; moisture on the blade may actually aid long cuts. Buildup will foul the cut. And back-trim the plate edge to remove bulge and flatten the steel backing.

parallel: I’ve added your “back-trim” to my notes to keep the metal backed plate flat on my magnetic letterpress base. To Briar Press Members who may not know what we are doing here is we are simply replacing very expensive hand set metal type with computer to plate. When you spend $50 to $140 dollars for a single font of type plus another $45 for a type case to store it - Photopolymer is very tempting. I have almost 50 cases of metal type so I have the best of the old and new at my finger tips.

Metal back polymer, than cut with Tin nibs or a metal shear always get back trimmed so they have a nice flat edge and the plate sits solid on the magnetic base. I make Plates professionally and can hold 4 pt type just fine if the Plate is processed right.

typenut: You have answered my next question about using photopolymer and Thin Line types faces such as Bernard Fashion and my favorite Greeting Monotone. I’m thinking a ultrasonic cleaner and no hand wash with a brush that may damage the fine line type - I think we are talking 2 points here. Any comments?

typenut: I have your email regarding brush v. ultrasonic cleaner for these plates. A Boxcar brush and NO ultrasonic cleaner! Thank you very much for this advice. Actually, after opening one of the plates from it’s wrap I thought no-way with an ultrasonic unit. I also calipered it at .060 after removing the protective cover film. I think that gives me a additional .007 punch on the paper when all I wanted was a .053 thick plate. I use Vandercook style Lollypops rather than Ludlow Slugs to set my presses…

typenut: Thanks for the additional email regarding a hair drier to keep the fine line type. Also the use of a pad to wash the polymer. Thank you

typenut: I copy your info on the ink stripe at 3-4 millimeters on the type form - a light “kiss” of ink. Sounds like I may have to “tape” the lollypops as well as the ink roller trucks on my 5x8 Kelsey to test this. It gets worse - I have a 10x15 C&P NS with Morgan Expansion Trucks and lotsa “tires” for it - I think I’ll stay away from photopolymer on this guy…at least for now…

you never tape the Lollipop (Roller gauge), than setting the rollers, people dial it in and than tighten the Screw or nut, whatever they have. That can change things drastically and you can chase that Rabbit all day. Than you see the right stripe, very gently turn whatever to tighten and keep testing until stripe perfect and roller tight.