Polymer Plates Sizing Help

Hello, everyone!

I just got a 9x13 Kelsey press and it came with a deep relief boxcar base. As I live in Canada, I am having a hard time finding a place to make the polymer plates that are the right size that boxcar suggests. I really rather not order from the U.S. to save of shipping and duty costs.

I know you are supposed to use a KF 152 (0.060) with the deep relief base, but I found a company that has a 0.045” and 0.067” option for the plates. They suggested getting a thicker adhesive for the backing of their 0.045” polymer plate. But I am wondering if anyone has any knowledge with polymer plates and if either of one of those plates could have the potential to print well with what I have?


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(author) frequently receive an *Ear Bashing* for posting too much, was to have posted an in depth response.
Hence the following:- perhaps key into Google or W H Y,
*Letterpress Printers mounting base height,* first entry that appears is usually >Moana Road Press< out of Wellington, New Zealand.
First full paragraph, BASE HEIGHT - Excellent resume, regarding the above query, perhaps read carefully first paragraph, last line, i.e. Its easy to slip etc., etc.,

If you live in Ontario (as I do), there’s Sterling Marking Products in London, ON


or KDS Graphics in Scarborough, ON (don’t know if they have a website).

I’m pretty familiar with plate and printing heights, so if you want to email me through Briar Press, feel free to do so

Check with the supplier make sure it is the right durometer for letterpress. I would look at no less than .095” for a tabletop press. Not sure where the supplier is, make sure not a flexo plate. If Toronto is it KDS Graphics? They have supplied the proper thickness in the past quite a few years ago.
I have a homemade exposure unit and get raw materials from Williamson’s in Grimsby ON. Or use the unit at the local museum which has an A4 unit.

TripleJ has good recommendations. As stated, make sure the platemaker knows you want a letterpress plate, which is harder (higher durometer). Durometer is a measure of the plate’s hardness or softness.

Flexo plates are softer and not what you want. (The flexo printing process is what most of the plastic bags in the grocery store, as well as other things, are printed by).

If I owned a .853 base which uses .059 plates as you have, and if I found it easier and cheaper to purchase standard .037 letterpress plates, I might try seeing if I could find a .022 thick material such as sheet aluminum online or even chipboard and slip behind the base to raise it up for use with .037 plates as an experiment. If it didn’t work well, like maybe the printing surface was too uneven I wouldn’t be out much for having tried it but if it did work I might save quite a bit over time.
Just a thought.

Further to what Bruce cpd mentioned above I have printed kf 95 plates using a deep relief base backed up by a .020 sheet of mylar cut to fit behind the chase. It has worked very well.

Great!! Thank you all for the help!!