How to print with the Boxcar Base
Since the Boxcar photopolymer plates + our adhesive + the Boxcar Base equals a type-high surface, you can print our polymer plates just like lead type.
1. Clean off your base and mount the base in your press. Between print runs, the Boxcar Base’s surface might have gotten dusty or dirty. Just as you would clean the bed of a press before putting any type down, make sure the Boxcar Base’s surface is completely clean before mounting a plate. Any dirt that remains on the Boxcar Base will cause some areas of your plate to ink and print unevenly -- and we’re guessing that you don’t want that. (Interested in more in-depth instructions on mounting your base?)
2. Adhere the plate onto your base's surface. Before peeling off the silicone paper backing that covers yours adhesive, make sure no air bubbles are underneath the silicone paper. A potential cause of uneven inking is air bubbles between the adhesive and the plate. If there are air bubbles, work them out with your fingers by pushing the air bubbles toward the plate’s edge. Prick any remaining bubbles with an exacto knife. Then you can push the air out from the hole you just made. Now peel off the silicone paper backing and stick the plate down on the Boxcar Base.
3. Registering your plate: The fact that you’re printing on a transparent, flexible and easily-cut plate makes registration a snap. You can line up the printing plate very accurately using the grid that comes on Boxcar Grid bases. Repositioning is easy – just peel the plate up, adjust, and smooth back down. Don’t worry about tearing the adhesive or harming this flexible plate – both are very durable. But as with any typographic surface though, be gentle and your printing and plates will thank you.
How do I prevent my gauge pins and grippers from smashing into my base? In other words, what do I have to worry about most when printing with a Boxcar Base on a platen press?
When using any kind of polymer printing base with your platen press, it’s vital to keep the gauge pins and the grippers from smashing into—and denting!-- your base. When the press goes to impression, make doubly sure – no, make triply sure – that the gauge pins and grippers will not impact the Boxcar Base’s surface. Here’s how to do this.
You must carefully place your gauge pins on the platen to avoid hitting the base. Place the gauge pins below and beyond where the base will sit in the chase and feed paper to the far bottom corner of the platen. In addition, place the grippers to the left and right of where the base sits in the chase. This will keep the grippers and gauge pins from contacting the base when the press closes for impression. If you need to use the grippers, keep them outside the base but construct a paper (or tape or string) frisket between them to hold the paper.
You might find it easier to position gauge pins if you print on sheets larger than the final trim size, especially if you have a quarter inch margin or less on either of your feed edges. This will move the gauge pins farther from the printing area and from the base – reducing the likely hood of a gauge pin/base collision. Print on the largest possible sheets and trim them down after printing.
4. Take an uninked impression of the plate. If possible, it’s not a bad idea to take an unlinked impression of the plate before going any further. This impression firmly attaches the polymer plate at type high, ensuring that the first pass of the inking rollers meets a type high surface.
5. Inking your polymer plate: Polymer plates pick up ink pretty much the way lead type does. In general, because polymer provides such a flat printing surface, you might not need your rollers quite so low as with lead type. Also, many of the plastic-backed plates we recommend for use with the Boxcar Base have a matte surface, which allows for ideal control over inking while you’re printing.
What will I need to do to my platen press before printing with polymer and a Boxcar Base (especially if my printing is blobby and/or has a "halo")? i.e. how do I add tape to my rails?
Every platen or lever press has wear on the rails and needs tape on the rails to raise the rollers to the right height. This is whether you use lead type or polymer--although the problem surfaces more frequently on polymer if the roller rails aren't set correctly. You have to build up the rails that the roller trucks travel on so that the rollers just grace the surface of the form. The best way to do this is to add equal layers of masking or strapping tape to each rail. Keep building up the rails in this fashion until whatever you're printing doesn't ink up at all (i.e. bring the rollers up just past the point where the rollers ink the plate). Then take off one layer of tape so that the rollers drop down with minimum contact to the plate. This will keep ink from getting on the backing of the plate and the base, and it will also help make your printing crisper. It's not uncommon to have to add as much as a 1/16"--or sometimes 1/8"--in tape in order to get the rails to the right height. These presses are often 100 years old and have 100 years of wear that you have to overcome. We do not recommend that you adjust your trucks or printing plate/base for this problem. Better printing results from type-high rollers. After you add tape to your rails, we recommend using a roller gauge to perfect the height of your rollers.
What are roller gauges and why do I need them?
Roller gauges are especially indispensable with a platen press. Letterpress rollers need to be positioned just right in order to deposit a thin film of ink onto the surface of the form, without squeezing ink over the edges. A roller gauge will help you accurately measure the height of your rollers so you can produce the crispest printing that your press is capable of. We sell roller gauges, precision ground to type high, which are also very fashionable.
When your rollers are positioned correctly, your printing will look beautifully crisp. This is because correctly positioned rollers deposit a thin film of ink onto the surface of your printing plate (without squeezing ink over the plate’s edges). But if your rollers aren't positioned at the right height, your printing will have a halo effect: dark around the edges and/or chunkier/blotchier than it should be. If you ever notice ink on the back of your polymer plate or on your base -- it's a roller gauge emergency! Adjust your rollers now! Here’s how.
Step 1. While your press is inked up, remove the chase (on platen presses) or the base (on a Vandercook).
Step 2. We recommend checking the roller height in the four corners of the press bed. We’ll start in the upper right hand corner. Engage the form rollers and position them over the upper right corner of the bed.
Step 3. You will be pulling a stripe of ink on the round surface of the roller gauge. Pull the gauge underneath the form rollers so that a stripe of ink is transferred to the rounded surface of the gauge’s cylinder. Measure the stripe of the ink: you want your ink stripe to measure 3/32”. If the strip of ink is less than 1/16”, you’ll have difficulty consistently inking your plate (some areas will appear too light, and some areas will appear too dark). If your strip of ink is wider than 3/32”, your rollers put too much pressure on your plate and cause your printing to be chunky/blurry.
Step 4: On a platen press, to adjust the height of your form rollers: add tape to the rails that the roller trucks ride on. You may have to add several layers of tape. Scotch or masking tape is frequently used for this. If you’re using a press other than a platen press, consult your manual as to how to raise your form rollers.
Step 5: Repeat steps three and four in each corner of your press bed.
Step 6: When your rollers are positioned correctly, you should pull identical 3/32” stripes of ink from the four corners of the press bed, and your printing should be both crisp and beautiful!
If you continue to notice inconsistencies in your inking after adjusting your roller height correctly, you may need to purchase new rollers and, if using a platen press, roller trucks as well.
6. Now print!
7. Clean off your base & plates. If you get ink on your base, clean it immediately with any press wash. You want to try and remove ink from your base before it’s dried on the base. If saving your plates, you'll want to clean those off as well. Check out our maintenance page for more specific instructions.
8. Store your plates. You shouldn’t have to apply adhesive when you reprint your plate. When you’re done with your press run, pull your plate off the base and replace the silicone lining paper on the adhesive-side of the plate. Make sure that the silicone paper hasn’t attracted any dust or dirt before you press it back on the plate. Also make sure no dust, dirt or grime gets on the adhesive. Cleanliness is key! If your adhesive becomes dirty, just pull off the old adhesive and replace it with fresh adhesive available from Boxcar Press .
Please tell me, very specifically, how to put new adhesive on an old plate.
This should be a pretty easy process.
First, peel up the old adhesive to remove it. Since it holds onto the plate strongly, you can potentially kink the plastic backing if you're not careful. We recommend that you lay the plate face down on a flat surface. Hold the plate down with one hand while peeling the adhesive off with the other. Try and keep the plate from flexing inordinately while you carefully tug the adhesive off the back of the plate. The adhesive might tear into pieces, but you can simply pull it up in strips.
Now, put on the new adhesive. Make sure you're putting down the side of the adhesive covered with the brown release paper onto the plate. The side with the pink release paper attaches to the base. When you first mount the adhesive to the plate, start with one side of the plate and roll out the adhesive so that it makes as few bubbles as possible. If the bubbles happen, work them out with your fingers or pierce them, through the adhesive, with an Exacto knife or awl. You should be able to get all the bubbles out at this point.
If bubbles form underneath the plate when you mount it to the base, first try working these out to the edges of the plate with your fingers. If that fails, you can puncture the bubbles by sticking an Exacto knife through the plastic backing of the plate to re
lease the trapped air.
To preserve your plates for prosperity and posterity, the manufacturers recommend storing your plates in a constant humidity between 50% and 60%. In the very least, avoid extreme fluctuations in humidity. You can maintain a constant humidity by storing your plates in a ziplock bag. Keep your plates away from ultraviolet light that will crack your plate.
