Aluminum base + adhesive + plate

Hi everyone,

I’m having a machinist machine a base for me. We’re starting with a 1” thick plate, and milling it down to…….

Originally I told him .875” (7/8) because I read it on the Dolce Press blog.

But then I started to wonder…

I’ll be using KF95 plates which are .037” so…..

.918” - 0.37” = 0.881

Then, how does the adhesive film play into the equation?

I got a pretty good film by a national brand which is ultra thin.. I tried it out and it sticks very well.

So.. should I machine it to .875” or .881” or something else?

I’m sure the film is probably a couple of micras, not sure how much, it’s really really thin.. thinner than Scotch tape.. much thiner even. Like an onion skin or thinner.

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Your tape supplier should be able to tell you how thick your tape is. Add that to the height of the plate and subtract that from .918


I am in the process of doing something similar but I think you have the wrong measurements. Boxcars says that the KF95 is .04 thick but the 94SB plate is .037.

I don’t know if those measurements are taking into consideration the adhesive that comes on the plates when you order or not.

If what I am doing works I plan to post the results. I hope you do likewise.

Sure thing Caleb, I will gladly post my findings and photos!

Thanks Lammy, I’ll see if I can find that.

start thicker. it is much easier to mill mat’l off than to mill it “on”.

I just measured some of my bases with a micrometer.

My boxcar deep relief base is 0.854 inches tall, my standard height boxcar base is 0.875 inches tall. My bunting magnetic base is 0.861 inches tall.

Not saying you should use these measures, but they will give you a sanity check on any numbers you come up with.


Have the base machined to .854” high.
It will then work with .064” 16 gauge mag or copper plates
by taping around the edges of the dies with Pg-21 masking tape.
For Boxcar style peel off plates, put a sheet of 24# paper behind the base for the .060” plates or 2 sheets of cardstock that measure .027” total behind the base if using the .037” peel off plates.
The steel backed photopolymer plates that are .060” work fine by taping around the edges, and again have a sheet of 24# paper behind the base to bring it up to .918”.
You must have good rollers that are adjusted correctly to use these bases and plates.

I actually decided to go with .875 because that allows me to go down if I need to.
Thank you guys for your input, specially Alan for taking the time to measure his bases.
I will report back. I told the machinist to start, but he says he’ll start tomorrow.. hey why do it today if it can be done tomorrow, right? :(

Great.. I confirmed that the adhesive is .006 +/- 10%
Which brings us to this equation:

0.918 - 0.037 (kf95) - 0.006 = 0.875

A sane and happy number :)

So hopefully this + my roller setting gauge and proper packing I’ll be able to get some really crisp prints.

Thanks everyone.



Actually I was wrong. The polyester film with adhesive is only .0005 ”

So I’m 5.5 mils short.. How will I bring the base up to that height?

I don’t know what #24 paper is.

I might just use an adhesive which is 6 mils in thickness.. But have no idea where to get it locally.

I’m sorry to bug you all, but what do you suggest?

Should I machine it down to 0.881 and use the 0.0005 adhesive? or machine to 0.875, use the 0.0005 adhesive and bring the plate up?

I can’t decide, I have no experience with aluminum bases, photopolymer and adhesives, and I’m trying to find a system that will work with local supplies. I have no quick access to Boxcar..

I personally think that if you go with the .875 then you can at least add packing either behind to bring it higher if need be. It seems that the photopolymer plates need to just get a light touch of the rollers so better to be low than to high.

Anyways that is the direction I am going with, that is the .875. After all as Allen said that is what boxcar is selling their standard bases so I don’t think you can go wrong.

That’s true, Caleb, you do raise a good point.
I’m just worried that I’ll end up with the wrong combination of things if I don’t get a thicker adhesive.
The one I got is definitely not re-positionable on the plate.
You have to discard it after use because it’s really good in adherence, but at the same time so thin, it makes it very fragile.
So I guess the next thing would be to figure out a good sticky back.
I’ll go with the boxcar spec, I guess I can’t go wrong.

:) Thanks for putting my mind at peace.

Well.. I went with the 0.875.. and it turned out pretty well. I think the machinist did a good job, I tested out the plate today, and it worked great. Here’s a test print I scanned of this bear in line half tones.

image: bear.jpg


I like it. Very cool.

I don’t know if you have checked out 3M products. I have used them in the past for non printing work. If you call the product help line and tell them what you are doing the specs you need etc. they are actually really good at getting you the right product. There help line people must get a good wage because they are not dumb, at least that has been my experience.

That is a good bit of advice, I will do that.

I used to buy form I don’t know if they are the best source anymore but good place to start.

I think you don’t want a “double sided” tape. It should be called a transfer tape, if my memory serves me correct. It is adhesive on a film but you put on the “tape” and peal off the backing just leaving the adhesive on the plate you want to stick. You many already know this. I am sure that boxcar is using a 3M product like this already if not the people who make the photopolymer in the first place.

Here’s another thread on a very similar topic. I want to point out that lists a bazillion tapes, for most of which they list the properties, including thicknesses.