photopolymer what?

Ok, like most people who are posting new topics here, I’m a beginner. I’ve been looking at to have some of my designs made into plates for printing (I don’t yet have a press, but am looking into the C&P 5x8 tabletop press - the discussions here have been helpful in making that decision)

I feel like i’m missing something when it comes to having plates made. Maybe this is because I haven’t actually printed anything yet. Here are all the questions that are getting bounced around in my head, maybe some one can shed some light on it, or even just talk to me like a first grader and tell me step by step what i want to do in having plates made

1. Will photopolymer be made out of plastic like a rubber stamp? and if so will it leave the kind of crisp impression that I love of letter press? Are they reusable? Are they hard to clean?

2. What is all this talk of the boxcar base? Do I need one? Which one? Why are they so dang expensive? Do I really need one? Can I make one from something else?

3. roller gages? ghosting?

I’m thinking this will all make more sense when i get my press. But any light ya’ll can shed on this subject would be helpful.

Thanks in advance

Log in to reply   8 replies so far

Rol- I’m not a big expert on Photopolymer…. but I’ve made and used quite a few in recent years. They are quite popular with the newer crop of letterpress folks.

The plates are much harder than a rubber stamp, and will give a nice clean impression. They aren’t any harder to clean than any other relief image block…. and yes you can re-use them if you take care of them.

You don’t HAVE to have a Boxcar base. I use wood to mount mine, and they work just fine. Other folks don’t like wood at all…. which is why Boxcar Bases exist, I guess.

Why are they so expensive? I didn’t know they were overly costly. BUT if they are it’s probably because they are precisely machined on both sides which is not cheap. Quality is always more costly than cheapo.

As far as roller guages and all of that goes, I’d reccommend spending a few hours at the Boxcar folks’ web-site. Even if you aren’t going to use their products, they have a lot of good info that will help you out.

The plastic backed photopolymer that Boxcar makes has a sticky back so it mounts very nicely. The base they sell has a grid pattern so you can line up your plate with the grid to insure correct registration. The reason registration is important is because of two things: first thing is if the plate is lined up then it’s fair to say it’s lined up when you print on the paper and then it’s also lined up when trimming. Second reason is if you print two color then you can register the two plates to each other by the grid pattern on the base.

My first plate I received from Boxcar which was about 4 years ago I mounted it on wood and that was a huge mistake. When I pulled the plate up some of the wood stuck to the sticky back and I mean all kinds of wood fiber. The problem was I couldn’t re stick it because of a lot of the wood fibers and another reason is because of the fibers the plate didn’t lay flat. It’s vitally important that the plate lay flat on the base you use.

The base plus the photopolymer is type high, .918, type is .918, wood type is .918. However, if the metal type or wood type or mag. cut of copper cut is very old then it tends to wear down. But the important thing here is type high is .918.

If you have wood fibers under your photopolymer then the plate could be raised and it may sit at .94 in some spots and .918 in other areas. That is a problem.

There are a few people that sell bases here on the list and I’m sure they can help answer your question since I have been so long winded.


Casey is correct, if you are using a photopolymer plate you would want a dense base, preferably aluminum. Wood will simply not serve you well. Photopolymer is very sensitive to its environment. It will reveal whatever you ask of it, for better or worse.

If you are using polyester-backed plates that require a film adhesive, you have no choice. Boxcar is the only firm that makes a precision ground aluminum base for this type of plate.


You can gather the raw materials and make your own base. The folks at Dolce Press have info about it in their blog.

Wouldn’t some plastic laminate (as in counter top) solve the wood fiber problem?

Cheapie and easy base: use 1/2” MDF (medium density fiber board*), mount 1/4” plexi glass to it with carpet tape (be sure to cover mdf surface evenly with tape; don;t overlap or miss any areas, can affect how evenly your polymer plates print). Then, shim the base with chipboard to reach type high/however deep you want the impression.
The polymer plates will lift easily from the plexi, no wood chips!
*Make sure you get MDF that is not painted/coated with laminate. It can chip off and will affect how evenly your plates print.

My first base was made of plexiglass. In fact I still use plexiglass bases when I need to mortise a numbering machine into a form or maybe a magnesium cut. I use an acrylic cement to glue a 1/2”sheet and a 3/8” sheet together. Then I cut it to the desired size/shape with a material saw. If I remember correctly, It cost about $20 for a 12”x12” plexiglass base.
I have since purchased a few Boxcar bases because they are flatter and I like the grid.


I forgot to mention that I use a thinner plate on the plexiglass base. The total thickness (base, adhesive and plate) needs to be .918” or as close as possible.