Photopolymer Material Type.
We run a Heidelberg Windmill using KF 95 plates. The math is fine we are at type high all is good and printing fine. In order to get a greater hit especially on 40pt thicker stocks I need a taller relief in order not to bottom out. If I switch to KF152 I will get 20/1000 taller relief. While this will change the math for true type high am I over thinking this. The type high base norm I wonder if that came during a period where a deep hit was not a desired effect. Since can reset the rails and alter the packing for a thicker plate what other issues will I potentally face. I am interested to see what those of you with Windmills use for plates and any feedback would be appreciated
Western411, It has to be sticking with .918 every time. Resetting the roller rails is not a practical option. Polymer bases are available for both .95 and 1.52. I am lucky enough to have honeycombe mount and a supply of 1980’s lead shim so I can mount both types of polymer and just back pack under the shim to bring up to .918. I have not touched the rails for at least 5 years and that was only when I put on newly recovered rollers and rarely have problems with the backgrounds inking.
Hope the comment helps
Frank, thanks for the feedback. What started this thread was finding a way to get a deeper hit without having to bottom out. I knew I could get a another base but was trying not to spend the money. Each year letterpress printed work becomes a bigger amount of our work. It is something Vista Print cant do. We keep looking for ways to expand the creative edge by using the windmill to our advantage. Any feedback and your time is always appreciated and we respect all of you for helping
Additional comment. I am also wondering how many shops use both style of plates. Since our clients think it is all about the hit they don’t understand the math and we thought this may be a possible solution. With 40pt Crane we can hit so much and the plate will bottom out. With a taller plate we can get a bigger hit at least in theory
If I need really deep punch because the client really wants that look, I order mag-plates with deep relief etching, rather than use the KF152, since the difference between them and the KF95 is minor. My vendor does these specifically for impression work. Then add hard packing if necessary.
I also dampen the stock, not sure if that works on the windmill though :)
Kimaboe, I think you have the right solution for deep emboss.
I have just had a look at some magnesium hot foil blocks and they would be ideal. Just a case of finding the right base for them. It could be wood or I have dowel mount , which with the magnesium block is only 0.007 of an inch shy of .918.
For now we want to take photopolymer to the max it can do. We have considered deep etch copper either 16 gage or .250. I happen to have an old foil base that is out of service - burned out rods. It work fine for for the .250 but starts to get costly compared to photopolymer since we generally jam a number of small plates on to one die and then cut them apart. We may try the deep etch 16 gauge on our regular photopolymer base just to see the results.
I missed this thread earlier— I only run 1/4” copper foil engravings for printing. I mount on sterling base with sterling toggles. It’s worked really well for years now. BTW a 9 x 12 base from Sterling is $945 as of 2024. But, I’m looking for L shaped pieces for another lockup before I buy the 9 x 12. The copper engravings are hard to destroy, and I have some with over a million impressions and very little wear.
Regarding cost, I’ve been pleased with both Metal Magic and Owosso Graphic Arts.